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ABSTRACT

Background: This research aims to determine the impact of feed on ewe milk quality in two sheep farms located in the Chlef province, focusing on two types of diets: one based on a concentrate diet with straw and the other on a diet based solely on grazed grass.

Methods: Individual milk samples from eight ewes (complete evening milkings) were collected for physicochemical analysis. Simultaneously, a chemical composition analysis of the grass was performed.

Result: Our analyses demonstrate an increase in butyrate levels and a reduction in protein, mineral and dry matter levels over time in both farms. The chemical analysis of the grass reveals an increase in crude fiber accompanied by a decrease in total nitrogen. Analysis of variance indicates that pH has no significant impact; however, acidity, mineral composition, fat content, protein percentage and dry matter have a highly significant influence (p<0.01). Thus, diet influences the quality of ewe’s milk.

INTRODUCTION

Recent studies on consumption show a significant demand for dairy products, requiring external inputs to meet market demand (Sahraoui et al., 2024). Sheep farming systems in Mediterranean regions play an important role in supplying milk and dairy products, particularly in rural areas where these products constitute an essential source of animal protein. Sheep’s milk is especially valued for its nutritional and technological qualities, as highlighted in several studies (Maurer and Schaeren, 2007; Labioui et al., 2009; Pirisi et al., 2001).
       
However, the physicochemical composition of ewe’s milk is highly variable and depends on numerous factors, among which diet plays a central role. Indeed, several studies have shown that the type of forage, concentrate intake and access to pasture directly influence milk production and milk quality (Nudda et al., 2019; Caraba and Caraba, 2023; Bennato et al., 2022). Other factors such as breed, stage of lactation, age of the animals, udder health, milking conditionsandseason can also affect these parameters (Haenlein, 2002; Pirisi et al., 2001; Bocquier and Caja, 2001).
       
In pastoral systems, variations in the availability and quality of forage resources make milk production particularly sensitive to environmental conditions (Bocquier et al., 1997; Mierlita, 2022). This situation is particularly evident in the semi-arid and arid regions of Algeria, where sheep farming is a major agricultural activity (Taherti and Kaidi, 2018). The middle Cheliff plain, which can be considered a dairy basin, is representative of the national problem (Belhadia et al., 2009).
       
The Middle Cheliff plain and more specifically the Chlef province, represents a significant dairy basin characterized by climatic diversity between the north and south of the region. The north benefits from a mild and humid climate, while the south experiences hotter and drier summers and cold, rainy winters. This climatic variability directly influences the availability of forage resources, particularly natural fallow lands, which constitute a significant pastoral resource estimated at approximately 3.8 tonnes of dry matter per hectare (Salhi et al., 2019; Barker et al., 2025). It is worth noting that grazing-based systems are particularly sensitive to variations in forage availability.
       
However, in recent years, the reduced availability of natural pastures due to droughts has led many farmers to change their feeding practices by incorporating more concentrates and preserved forages. This transition raises the question of the impact of different feeding systems on the quality of milk produced in this region.
       
In this context, this study aims to evaluate the effect of two contrasting diets: A grazing-based system and a system combining concentrates and straw on the physicochemical parameters of ewe’s milk (pH, acidity, butterfat content, protein content, dry matter and mineral matter) in two sheep farms located in the municipality of El Karimia, wilaya of Chlef.

MATERIALS AND METHODS

Farm selection and sheep selection
 
Two sheep farms with contrasting farming systems were selected to compare the effect of feeding methods. The farms were chosen based on animal availability, accessibility of grazing areas, farmer acceptanceandthe overall health of the ewes.In each farm, four ewes were selected homogeneously according to the following criteria: age approximately two years, live weight between 38 and 40 kgandsimilar stage of lactation. This selection aimed to limit the effect of individual factors on the studied zootechnical performanceandobservations were carried out repeatedly to ensure data reliability.
       
Farm 1 represents an intensive system, in which ewes are fed primarily on concentrates (milk concentrate, fattening concentrate, bran, cornandbarley) supplemented with straw. The individual daily ration is approximately 1 kg of concentrate and 2.5 kg of straw, adjusted by the farmer according to the stage of lactation.
       
Farm 2 corresponds to an extensive system based mainly on grazing natural fallow land, with an average grazing time of 8 hours per day, without significant input of concentrates.
 
Milk collection and storage
 
Milk samples were collected weekly between February and April 2024 on the two farms studied. To guarantee the microbiological quality of the samples, strict aseptic conditions were observed. Before milking, the operator’s hands were disinfected and the ewes’ teats were cleaned with a clean cloth soaked in a diluted disinfectant solution.

Milk was collected during the evening manual milking in sterile 50 mL tubes. Each sample was immediately identified (date, ewe number, diet) and then stored at 4°C until analysis. The time between collection and analysis did not exceed 24 hours to limit any alteration of physicochemical properties.
       
Samples were taken from a constant number of four ewes per farm, with weekly repetitions, ensuring the representativeness of the data over time.
 
Characterization of food and wastelands
 
Food samples were collected monthly. The floristic survey of the rangelands was carried out using the zigzag method to identify the plant species present in each plot.
       
Rangeland productivity was estimated in terms of dry matter (DM/ha) and the leaf-to-stem ratio.
       
Representative samples (300 g) were dried at 60°C for 48 hours and then ground for further analysis.
       
Dry matter (DM) was determined by oven drying at 105°C for 24 hours. Mineral matter (MM) was obtained by incineration in a muffle furnace at 550°C. Organic matter (OM) was calculated by difference (OM = 100-MM).
       
Crude fiber (CF) was determined using the weende method, while total nitrogen (TN) was analyzed using the Kjeldahl method.
       
The analyses followed the recommendations of AFNOR and INRA standards (Jarrige, 1988).
       
Energy values (NEL and NEg) and digestibility of organic matter were estimated from the equations of Chibani et al. (2010):
 
dMO (%)= (-0.8597 CF) + (1.1514 Ash) + 79.06
 
NEL/kg DM= (-0.0018 CF) + 1.3585
 
NEg/kg DM= (-0.0021 CF) + 1.350
 
DCP (g/kg DM)= 8.82 × CP (%) -22.43
 
Analysis of concentrated feed
 
Concentrated feed was analyzed at the livestock feed manufacturing unit (SENDJASNI) using near-infrared spectroscopy (NIRS, FoodScan DS2500).
       
Chemical analyses of barley and straw were not performed experimentally. The values used were taken from literature data (Arbouche et al., 2008; Wang et al., 2022), which was clearly stated to ensure transparency in the data used in the study.
 
Physicochemical analysis of milk
 
A total of 88 milk samples were analyzed in AinDefla at the laboratories of the ARIB and WANISS dairies in BirOueldKhelifa, KhemisMiliana. pH was measured using a pH meter. An acidimeter, equipped with a burette connected to a bottle containing sodium hydroxide (10-1) via a small tube, was used to determine the Dornic acidity. Total dry extract was determined by steaming, fat content by butyrometer, ash content by incinerationandprotein content by the Milko Scan instrument.
 
Statistical analysis
 
The results obtained were statistically analyzed using XLSTAT 2016 software. Quantitative data were described using the mean and standard deviation. We performed an analysis of variance to compare the milk quality of two diets. Multiple pairwise comparisons between the different sampling periods were carried out using Tukey’s post-hoc test.
       
In this study, the effects of explanatory variables or their interaction were considered statistically significant at p<0.05.

RESULTS AND DISCUSSION

Floristic composition and nutritional value of fallow land
 
The floristic analysis of grazed areas revealed a plant diversity composed mainly of Melilotus infesta, Daucus carota, Medicagopolymorpha, Vicia sativa, Sonchusoleraceus, Erodium moschatum, Erodium malacoides, Brassica rapa, Raphanus raphanistrum, Calendula arvensis, Bromus hordeaceus, Anacyclus clavatus, Emex spinosa, Bromusmadritensis and other spontaneous species characteristic of Mediterranean fallow land.
       
The nutritional value of grazed grass varies according to the month of sampling (Table 1). A progressive increase in productivity was observed from February (1.51 TDM/ha) to April (2.67 TDM/ha), accompanied by a decrease in the leaf/stem ratio.

Table 1: Nutritional value of grass.


       
Dry matter increased gradually (from 16.66% to 29.77%), while total nitrogen decreased (from 28.53% to 14.58%). A similar trend was observed for organic matter digestibility, which decreased sharply between February and April (from 80.76% to 32.99%).
       
The energy values (NEL and NEg) have decreased slightly over time, indicating a progressive degradation of the nutritional quality of the forage.
 
Nutritional value of concentrates and straw
 
Concentrates have higher protein and energy content than cereal straw (Table 2). Concentrates (milk feed, fattening feed, corn, wheat bran, barley) have protein contents ranging from 7.37% to 18.26%, while straw has much lower values (1.88-4.60%).

Table 2: Nutritional value of concentrated feed for sheep and cereal straw.


       
Fiber content is low in concentrates (2.37-7.8%) and very high in straw (75-87.4%), confirming its role as a roughage with low energy value.
       
Starch is particularly high in corn (67.44%), making it a major energy source. These results confirm the clear difference in composition between the two types of feed.

Physicochemical quality of milk
 
Samples were obtained from raw milk of healthy ewes with healthy-looking udders and no signs of redness, heat, or edema for each day of sampling. The milk samples were bright white with no unusual odor.
       
The physicochemical characteristics of the milk are shown in Fig 1. The pH of the milk remained stable in both farms, ranging from 6.61 to 6.75, with no significant difference. The acidity of the milk ranged from 19.67°D to 24°D, with slightly higher values in the concentrate-fed system.

Fig 1: Physicochemical characteristics of milk.


       
Fat and protein content were significantly higher in the farm receiving a concentrate and straw-based ration compared to the pasture-only system. The milk dry matter content is also higher in farm 1 (15.88 to 19.44 g/L) than in farm 2 (13.82 to 17.04 g/L). The mineral content follows the same trend, with slightly higher values in the intensive system.
 
Effect of diet on milk quality
 
Statistical analysis (Table 3) shows that diet has no significant effect on pH (p>0.05). However, highly significant differences (p<0.0001) are observed for acidity, fat content, protein content, dry matter and mineral content. Ewes fed a concentrated ration produce milk richer in fat and protein than those raised on pasture.

Table 3: Effect of diet on ewe’s milk quality.


       
The results obtained show that the nutritional quality of the pasture varies significantly over the study period, with a progressive increase in dry matter and crude fiber, associated with a decrease in total nitrogen and digestibility. This evolution is mainly explained by the maturity stage of the plant species, where the transition from the vegetative to the senescent stage leads to increased tissue lignification and a decrease in the protein value of the forage. This result is consistent with the observations of Demarquilly (1987), who reported an increase in fiber with plant age. According to Boudechiche et al. (2010), the mineral content decreases with age. According to Demarquilly and Andrieu (1988), leaves contain more ash than stems and this concentration tends to decrease with the progression of development and the age of the plant. Compared to Salhi (2013) study on grass, the protein concentration is low.
       
This decline in forage quality has direct repercussions on milk composition, particularly protein and fat content. Indeed, the data from this study show superior physicochemical values in milk from the system receiving concentrates compared to the system based solely on grazing. This difference can be attributed to the higher energy and nitrogen density of the supplemented rations, which promotes greater udder synthesis.
       
The role of diet in modulating milk composition has been widely demonstrated. Bocquier and Caja (2001) showed that the energy level of the ration directly influences milk fat content. In our study, the higher fat values in the concentrate system confirm this relationship. Furthermore, the decrease in protein content observed in the pasture system may be linked to the decline in forage nitrogen content over time.
       
The acidity and pH of the milk remained relatively stable between the two systems, indicating that the sanitary and hygienic conditions of milking were generally well controlled. These results are consistent with the values   reported for ewe’s milk under similar conditions (Mathieu, 1998; Benlahcen et al., 2013).
       
The dry matter and mineral content of milk follow the same trend as the protein and lipid components, with higher values in the intensive system. This suggests better nutrient availability in the supplemented ration, allowing for more efficient synthesis of milk constituents. This finding is consistent with Gonzalo (2005), who emphasizes the importance of nutritional supplementation in influencing the variation of milk dry matter.
       
The results concerning the pH of ewe’s milk fall within the ranges generally reported in recent literature (6.4–6.8), confirming the buffering effect exerted by phosphate, citrate and protein systems, particularly caseins. Recent studies show that this parameter remains relatively stable but can be influenced by diet and stage of lactation (Claeys et al., 2021; Park, 2021). The slight alkalinity observed in some samples could be related to a diet rich in green forage or to physiological variations in the animals.
       
The higher titratable acidity of sheep’s milk compared to other species is consistent with its high dry matter and protein content. Recent studies confirm that sheep’s milk has a higher acidity due to its high concentration of caseins and minerals (Pulina et al., 2022). This characteristic gives sheep’s milk better technological suitability, particularly for cheesemaking.
       
The observed fat content, close to or above 7%, is consistent with values reported in several recent studies. It is well established that the fat content is strongly influenced by diet, particularly the proportion of fiber and fatty acids in the ration (Nudda et al., 2020). Furthermore, the stage of lactation plays a crucial role, with a progressive increase in fat content towards the end of lactation, a phenomenon confirmed by numerous contemporary studies (Pulina et al., 2022; Lankri et al., 2024).
       
Regarding protein, the high values recorded in this study exceed those generally reported, which could be attributed to genetic, nutritional, or environmental factors. Recent research highlights that the protein composition of sheep milk is particularly sensitive to feed quality and rearing conditions (Park, 2021; Claeys et al., 2021). The high protein content of sheep milk is a major asset for its nutritional and technological qualities.
       
The observed total solids and ash content confirm the high nutritional density of sheep milk. Recent studies indicate that these parameters are generally higher than in cow and goat milk, due to the greater concentration of nutrients (Pulina et al., 2022). However, the variations observed between farms can be explained by differences in farming practices, particularly the type of feed and climatic conditions.
       
Furthermore, the impact of nutritional supplements, particularly lipid intake, on milk composition has been widely demonstrated. Enriching the ration with fatty acids significantly alters the milk lipid profile, increasing the proportion of unsaturated fatty acids (Nudda et al., 2020). This phenomenon is of significant nutritional interest for human health.
       
It is also important to note that the differences observed between the two systems cannot be attributed solely to diet. The stage of lactation constitutes an additional factor influencing milk composition, particularly the variation in butterfat and protein levels over time. Several factors, including breed, season, stage of lactation and litter size, significantly influence the milk quality of goats (Singh et al., 2026). The incorporation of feed additives in dairy animal nutrition plays an important role in improving milk production and overall performance (Ahmed et al., 2022). Furthermore, reducing the proportion of barley grain in ewe diets during the third stage of lactation did not adversely affect milk yield or its composition, representing an economically beneficial strategy through reduced feeding costs. In addition, supplementation with yeast in low-barley, high-fiber diets improved energy utilization efficiency, thereby enhancing the nutritional value of the ration (Almallah et al., 2021).
       
Finally, although the literature confirms the importance of diet in milk composition (Nudda et al., 2021), the results of this study highlight that systems based solely on grazing exhibit greater variability, linked to the seasonal fluctuation in the availability and quality of forage resources.

CONCLUSION

Analysis of physicochemical parameters revealed that dairy ewe’s milk is a sought-after feed with high nutritional value (fat content, mineralsandprotein levels). The results showed a variation between the two farms with different feeding regimes. Milk from grass-based diets differed from milk from diets based on straw and concentrated feed. The diet affects the analyzed milk parameters. Despite the observed drought, the physicochemical quality of the milk from grazed grass remains acceptableandit is the most economical option. The fat and protein levels are above 4%. To improve the quality of the ewe’s milk, supplementation with concentrates is necessary. Further analyses would be desirable, such as those of fatty acids, amino acids, vitaminsa nd minerals, all comparing the results with those from other diets.

ACKNOWLEDGEMENT

The authors express their deep gratitude to the livestock farmers for their invaluable logistical support and technical assistance throughout the study, as well as to the dairy farmers for their cooperation and adaptability during the experimental period, their collaboration and dedication were essential to the success of this research project.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered to. No ethical approval was required as this is a characterization article of a potential animal feed ingredient.

CONFLICT OF INTEREST

The authors declare no conflict of interest.

REFERENCES


  1. Ahmed, N.A., Vishwanath, B.G. and Rangesh, P. (2022). Evaluation of impact of chelated mineral mixture formulation supplementation on milk quantity and milk quality parameters in lactating dairy cows under field conditions. Asian Journal of Dairy and Food Research. 41(3): 272-277. doi: 10.18805/ajdfr.DR-1808.

  2. Almallah, O.D., Abdullah, M.N., Abbo, N.Y. and Hussien, N.G. (2021). Impact of yeast supplement to the rations contained different levels of barley grain in milk production and components of Awassi ewes. Asian Journal of Dairy and Food Research. 40(3): 295-298. doi: 10.18805/ajdfr.DR-221.

  3. Arbouche, H.S, Arbouche, Y., Arbouche, F. and Arbouche, R. (2008). Valeur nutritive de quelques variétés d’orge algériennes pour l’alimentation des ruminants. Recherche agronomique. 22. https://asjp.cerist.dz/en/article/46064.

  4. Barker, D., Chiavegato, M., Campbell, B. and Verhoff, K. (2025). Advances in Sustainable Sheep Pasture and Grazing. In: Sustainable Sheep Production Systems. Stubbings, [L, Phillips, K (eds)],  Burleigh Dodds Science Publishing. https://doi.org/10.19103/AS.2024.0147.13

  5. Belhadia, M., Saadoud, M., Yakhlef, H. and Bourbouze, A. (2009). La production laitière bovine en Algérie: Capacité de production et typologie des exploitations des plaines du Moyen Cheliff. Revue Nature et Technologie. 1: 54-62. https://asjp.cerist.dz/en/article/41188.

  6. Benlahcen, K., Mouloudi, F. and Kihal, M. (2013). Study of the microbiological and physicochemical quality of raw milk from cows exposed to environmental pollutants in the region of west Algeria. International Journal of Environmental Engineering Science and Technology Research. 1(9): 229-240. https://www.researchgate.net/profile/Kihal Mebrouk/publication/281450323_Study_of_the_microbiological_and_Physicochemical_quality_of_raw_milk_from_ cows_exposed_to_environmental_Pollutants_in _the_region_of_west_Algeria/links/55e83ed908aeb65 16262ff1f/Study-of-the-microbiological-and-Physicochemical -quality-of-raw-milk-from-cows-exposed-to environmental- Pollutants-in-the-region-of-west-Algeria.pdf.

  7. Bennato, F., Ianni, A., Florio, M., Grotta, L., Pomilio, F., Saletti, M.A.  and  Martino, G. (2022). Nutritional properties of milk from dairy ewes fed with a diet containing grape pomace. Foods. 11(13): 1878. https://doi.org/10.3390/foods11131878.

  8. Bocquier, F. and Caja, G. (2001). Production et composition du lait de brebis: Effets de l’alimentation. INRA Productions Animales. 14(2): 129-140. https://doi.org/10.20870/ productions-animales.2001.14.2.3734

  9. Bocquier, F., Guitard, J.P., Vacaresse, C., Van Quackebeke, E., Delmas, G., Guillouet, P., Lagriffoul, G., Morin, E. and Arranz, J.M. (1997). Estimation de la capacité d’ingestion et des phénomènes de substitution fourrage/concentré chez les brebis Lacaune conduites en lots. Rencontres Recherche Ruminants. 4: 75-78. https://agris.fao.org/ search/en/providers/122439/records/64775d2df 92238f9f1deeb4c.

  10. Boudechiche, L., Araba, A. and Touati, A. (2010). Effet du surpâturage sur la biodiversité, la productivité et la valeur nutritive des prairies au nord-est algérien. Rencontres Recherche Ruminants. 17: 63. https://journees3r.fr/textes3r/2010 0109-effet-du-surpaturage-sur-la-biodiversite-la-productivite -et-la-valeur-nutritive-des-prairies-au-nord-est-algerien/

  11. Caraba, I.V., Caraba, M.N. (2023). Effects of feeding management system on milk production and milk quality from sheep of the Turcana breed. Animals. 13(18): 2977. https:// doi.org/10.3390/ani13182977.

  12. Chibani, C., Chabaca, R. and Boulberhane, D. (2010). Fourrages algériens. 1. Compositions chimiques et modèles de prédiction de la valeur énergétique et azotée [Document technique, École nationale supérieure agronomique, Alger]. https://lrrd.cipav.org.co/lrrd22/8/chab22153.htm

  13. Claeys, W.L., Cardoen, S., Daube, G., De Block, J., Dewettinck, K., Dierick, K. and  Herman, L. (2021). Raw or heated cow milk consumption: Review of risks and benefits. Food Control, 120, 107591. https://doi.org/10.1016/j.foodcont. 2020.107591

  14. Demarquilly, C. (1987). Les fourrages secs: Récolte, traitement, utilisation. INRA, Paris. https://agris.fao.org/search/en/ providers/122621/records/647396be3ed73003714 ceb11.

  15. Demarquilly, C. and Andrieu, J. (1988). Les fourrages. In: Alimentation des bovins, ovins et caprins. INRA, Paris. pp 315-335. https:/ /hal.science/hal-02856328/.

  16. Gonzalo, C., Blanco, M., Linage, B., Beneitez, E., Martinez, A., Juarez, M. et al. (2005). Bulk tank milk quality of dairy sheep in Castilla-León region (Spain). Rencontres Recherche Ruminants. 12: 401. https://journees3r.fr/textes3r/2005 1021-qualite-physique-chimique-et-hygienique-du-lait- de-brebis-chez-les-troupeaux-du-bassin-de-castilla- leon-espagne/.

  17. Haenlein, G.F.W. (2002). Relationship of somatic cell counts in goat milk to mastitis and productivity. Small Ruminant Research. 45: 163-178. https://doi.org/10.1016/S0921- 4488(02)00097-7.

  18. Jarrige, R. (1988). Alimentation des bovins, ovinsetcaprins. INRA, Paris. https://hal.science/hal-02854912/

  19. Labioui, H., Elmoualdi, L., Benzakour, A., Elyachioui, M., Berny, E. and Ouhssine, M. (2009). Étude physicochimique et microbiologique de laits crus. Bulletin de la Société de Pharmacie de Bordeaux. 148: 7-16. https://www.socpharm bordeauxasso.fr/pdf/pdf-148/148-007-016.pdf.

  20. Lankri, E., Boudour, K., Belabdi, I., Bouhroum, N. and Aichouni, A. (2024). Effect of shelf life on physicochemical and biochemical parameters of camel milk. Asian Journal of Dairy and Food Research. 43(2): 361-367. doi: 10.18805/ajdfr.DRF-337.

  21. Mathieu, J. (1998). Initiation à la physicochimie du lait. Tec and Doc Lavoisier, Paris. https://agris.fao.org/search/en/providers/ 122439/records/6472298b77fd37171a73288b.

  22. Maurer, J. and Schaeren, W. (2007). Le lait de brebis : un aliment de haute valeur nutritive. Revue suisse d’agriculture. 39(4): 205-208. https://agris.fao.org/search/en/providers/ 122607/records/6472477453aa8c896304a754.

  23. Mierlita, D. (2022). Influence of feeding on different types of pasture on the fatty acid profile and health indices of goat milk. South African Journal of Animal Science. 52(5). https:/ /doi.org/10.4314/sajas.v52i5.08.

  24. Nudda, A., Battacone, G., Boe, R. and Pulina, G. (2020). Nutritional modulation of milk fatty acid composition in sheep. Small Ruminant Research. 190: 106148. https://doi.org/10. 1016/j.smallrumres.2020.106148.

  25. Nudda, A., Cannas, A. and Pulina, G. (2019). Nutritional approaches to improve the fatty acid profile of milk fat in sheep and goats. Options Méditerranéennes, Série A. 123: 73-82. https://om.ciheam.org/ressources/om/pdf/a123/0000 7862.pdf

  26. Nudda, A., Correddu, F., Cesarani, A., Pulina, G. and Battacone, G. (2021). Functional odd- and branched-chain fatty acids in sheep and goat milk and cheeses. Dairy. 2(1): 79-89. https://doi.org/10.3390/dairy2010008.

  27. Park, Y.W. (2021). Bioactive components in sheep milk. Small Ruminant Research. 200: 106377. https://doi.org/10. 1016/j.smallrumres.2021.106377.

  28. Pirisi, A., Piredda, G., Scintu, M. and Fois, N. (2001). Effect of feeding diets on quality characteristics of milk and cheese produced from Sardinian dairy ewes. Options Méditerranéennes, Série A. 46: 115119. https://om.ciheam.org/ressources/ om/pdf/a46/01600121.pdf.

  29. Pulina, G., Milán, M.J., Lavín, M.P., Theodoridis, A., Morin, E., Capote, J. and Caja, G. (2022). Invited review: current production trends, farm structures and economics of the dairy sheep and goat sectors. Journal of Dairy Science. 105(4): 2881-2904. https://doi.org/10.3168/jds.2021-21227.

  30. Sahraoui, H., Smili, H., Djouza, L. et al. (2024). Consommation du lait et produits laitiers caprins: Situation actuelle et perspectives. Journée scientifique nationale du GRAL. https://dspace.univ-ghardaia.edu.dz/xmlui/handle/ 123456789/9619.

  31. Salhi, H. (2013). Valeur nutritive des espèces spontanées de la plaine du moyen Chlef [Thèse de magistère, Université de Chlef]. http://dspace.univ-chlef.dz/handle/123456789/ 132.

  32. Salhi, H., Meziane, M., Noura, A., Ali-Benamara, B. and Bensaïd, A. (2019). Évaluation du potentiel fourrager des végétations de friche dans cinq localités de Chlef (Algérie). Fourrages. 237:  95-100. https://afpf-asso.fr/_objects/afpf_revues/ f237-salhi-3421.pdf.

  33. Singh, G., Sharma, R.B., Sharma, K., Kumar, A. and Sharma, L.K. (2026). Effect of environmental factors on goat milk and meat quality under field and farm rearing condition: A Review. Agricultural Reviews. 47(2): 275-281. doi: 10.18805/ag.R-2757.

  34. Taherti, M. and Kaidi, R. (2018). Productivité de la brebis Ouled Djellal selon le mode de conduite de la reproduction. Lebanese Science Journal. 19(1). https://lsj.cnrs.edu.lb/ wp-content/uploads/2018/04/LSJ-Mourad-Taherti.pdf

  35. Wang, B., Sun, H., Wang, D., Liu, H. and Liu, J. (2022). Constraints on the utilization of cereal straw in lactating dairy cows: A review from the perspective of systems biology. Animal Nutrition. 9: 240-248. https://doi.org/10.1016/j.aninu. 2022.01.002.
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    ABSTRACT

    Background: This research aims to determine the impact of feed on ewe milk quality in two sheep farms located in the Chlef province, focusing on two types of diets: one based on a concentrate diet with straw and the other on a diet based solely on grazed grass.

    Methods: Individual milk samples from eight ewes (complete evening milkings) were collected for physicochemical analysis. Simultaneously, a chemical composition analysis of the grass was performed.

    Result: Our analyses demonstrate an increase in butyrate levels and a reduction in protein, mineral and dry matter levels over time in both farms. The chemical analysis of the grass reveals an increase in crude fiber accompanied by a decrease in total nitrogen. Analysis of variance indicates that pH has no significant impact; however, acidity, mineral composition, fat content, protein percentage and dry matter have a highly significant influence (p<0.01). Thus, diet influences the quality of ewe’s milk.

    INTRODUCTION

    Recent studies on consumption show a significant demand for dairy products, requiring external inputs to meet market demand (Sahraoui et al., 2024). Sheep farming systems in Mediterranean regions play an important role in supplying milk and dairy products, particularly in rural areas where these products constitute an essential source of animal protein. Sheep’s milk is especially valued for its nutritional and technological qualities, as highlighted in several studies (Maurer and Schaeren, 2007; Labioui et al., 2009; Pirisi et al., 2001).
           
    However, the physicochemical composition of ewe’s milk is highly variable and depends on numerous factors, among which diet plays a central role. Indeed, several studies have shown that the type of forage, concentrate intake and access to pasture directly influence milk production and milk quality (Nudda et al., 2019; Caraba and Caraba, 2023; Bennato et al., 2022). Other factors such as breed, stage of lactation, age of the animals, udder health, milking conditionsandseason can also affect these parameters (Haenlein, 2002; Pirisi et al., 2001; Bocquier and Caja, 2001).
           
    In pastoral systems, variations in the availability and quality of forage resources make milk production particularly sensitive to environmental conditions (Bocquier et al., 1997; Mierlita, 2022). This situation is particularly evident in the semi-arid and arid regions of Algeria, where sheep farming is a major agricultural activity (Taherti and Kaidi, 2018). The middle Cheliff plain, which can be considered a dairy basin, is representative of the national problem (Belhadia et al., 2009).
           
    The Middle Cheliff plain and more specifically the Chlef province, represents a significant dairy basin characterized by climatic diversity between the north and south of the region. The north benefits from a mild and humid climate, while the south experiences hotter and drier summers and cold, rainy winters. This climatic variability directly influences the availability of forage resources, particularly natural fallow lands, which constitute a significant pastoral resource estimated at approximately 3.8 tonnes of dry matter per hectare (Salhi et al., 2019; Barker et al., 2025). It is worth noting that grazing-based systems are particularly sensitive to variations in forage availability.
           
    However, in recent years, the reduced availability of natural pastures due to droughts has led many farmers to change their feeding practices by incorporating more concentrates and preserved forages. This transition raises the question of the impact of different feeding systems on the quality of milk produced in this region.
           
    In this context, this study aims to evaluate the effect of two contrasting diets: A grazing-based system and a system combining concentrates and straw on the physicochemical parameters of ewe’s milk (pH, acidity, butterfat content, protein content, dry matter and mineral matter) in two sheep farms located in the municipality of El Karimia, wilaya of Chlef.

    MATERIALS AND METHODS

    Farm selection and sheep selection
     
    Two sheep farms with contrasting farming systems were selected to compare the effect of feeding methods. The farms were chosen based on animal availability, accessibility of grazing areas, farmer acceptanceandthe overall health of the ewes.In each farm, four ewes were selected homogeneously according to the following criteria: age approximately two years, live weight between 38 and 40 kgandsimilar stage of lactation. This selection aimed to limit the effect of individual factors on the studied zootechnical performanceandobservations were carried out repeatedly to ensure data reliability.
           
    Farm 1 represents an intensive system, in which ewes are fed primarily on concentrates (milk concentrate, fattening concentrate, bran, cornandbarley) supplemented with straw. The individual daily ration is approximately 1 kg of concentrate and 2.5 kg of straw, adjusted by the farmer according to the stage of lactation.
           
    Farm 2 corresponds to an extensive system based mainly on grazing natural fallow land, with an average grazing time of 8 hours per day, without significant input of concentrates.
     
    Milk collection and storage
     
    Milk samples were collected weekly between February and April 2024 on the two farms studied. To guarantee the microbiological quality of the samples, strict aseptic conditions were observed. Before milking, the operator’s hands were disinfected and the ewes’ teats were cleaned with a clean cloth soaked in a diluted disinfectant solution.

    Milk was collected during the evening manual milking in sterile 50 mL tubes. Each sample was immediately identified (date, ewe number, diet) and then stored at 4°C until analysis. The time between collection and analysis did not exceed 24 hours to limit any alteration of physicochemical properties.
           
    Samples were taken from a constant number of four ewes per farm, with weekly repetitions, ensuring the representativeness of the data over time.
     
    Characterization of food and wastelands
     
    Food samples were collected monthly. The floristic survey of the rangelands was carried out using the zigzag method to identify the plant species present in each plot.
           
    Rangeland productivity was estimated in terms of dry matter (DM/ha) and the leaf-to-stem ratio.
           
    Representative samples (300 g) were dried at 60°C for 48 hours and then ground for further analysis.
           
    Dry matter (DM) was determined by oven drying at 105°C for 24 hours. Mineral matter (MM) was obtained by incineration in a muffle furnace at 550°C. Organic matter (OM) was calculated by difference (OM = 100-MM).
           
    Crude fiber (CF) was determined using the weende method, while total nitrogen (TN) was analyzed using the Kjeldahl method.
           
    The analyses followed the recommendations of AFNOR and INRA standards (Jarrige, 1988).
           
    Energy values (NEL and NEg) and digestibility of organic matter were estimated from the equations of Chibani et al. (2010):
     
    dMO (%)= (-0.8597 CF) + (1.1514 Ash) + 79.06
     
    NEL/kg DM= (-0.0018 CF) + 1.3585
     
    NEg/kg DM= (-0.0021 CF) + 1.350
     
    DCP (g/kg DM)= 8.82 × CP (%) -22.43
     
    Analysis of concentrated feed
     
    Concentrated feed was analyzed at the livestock feed manufacturing unit (SENDJASNI) using near-infrared spectroscopy (NIRS, FoodScan DS2500).
           
    Chemical analyses of barley and straw were not performed experimentally. The values used were taken from literature data (Arbouche et al., 2008; Wang et al., 2022), which was clearly stated to ensure transparency in the data used in the study.
     
    Physicochemical analysis of milk
     
    A total of 88 milk samples were analyzed in AinDefla at the laboratories of the ARIB and WANISS dairies in BirOueldKhelifa, KhemisMiliana. pH was measured using a pH meter. An acidimeter, equipped with a burette connected to a bottle containing sodium hydroxide (10-1) via a small tube, was used to determine the Dornic acidity. Total dry extract was determined by steaming, fat content by butyrometer, ash content by incinerationandprotein content by the Milko Scan instrument.
     
    Statistical analysis
     
    The results obtained were statistically analyzed using XLSTAT 2016 software. Quantitative data were described using the mean and standard deviation. We performed an analysis of variance to compare the milk quality of two diets. Multiple pairwise comparisons between the different sampling periods were carried out using Tukey’s post-hoc test.
           
    In this study, the effects of explanatory variables or their interaction were considered statistically significant at p<0.05.

    RESULTS AND DISCUSSION

    Floristic composition and nutritional value of fallow land
     
    The floristic analysis of grazed areas revealed a plant diversity composed mainly of Melilotus infesta, Daucus carota, Medicagopolymorpha, Vicia sativa, Sonchusoleraceus, Erodium moschatum, Erodium malacoides, Brassica rapa, Raphanus raphanistrum, Calendula arvensis, Bromus hordeaceus, Anacyclus clavatus, Emex spinosa, Bromusmadritensis and other spontaneous species characteristic of Mediterranean fallow land.
           
    The nutritional value of grazed grass varies according to the month of sampling (Table 1). A progressive increase in productivity was observed from February (1.51 TDM/ha) to April (2.67 TDM/ha), accompanied by a decrease in the leaf/stem ratio.

    Table 1: Nutritional value of grass.


           
    Dry matter increased gradually (from 16.66% to 29.77%), while total nitrogen decreased (from 28.53% to 14.58%). A similar trend was observed for organic matter digestibility, which decreased sharply between February and April (from 80.76% to 32.99%).
           
    The energy values (NEL and NEg) have decreased slightly over time, indicating a progressive degradation of the nutritional quality of the forage.
     
    Nutritional value of concentrates and straw
     
    Concentrates have higher protein and energy content than cereal straw (Table 2). Concentrates (milk feed, fattening feed, corn, wheat bran, barley) have protein contents ranging from 7.37% to 18.26%, while straw has much lower values (1.88-4.60%).

    Table 2: Nutritional value of concentrated feed for sheep and cereal straw.


           
    Fiber content is low in concentrates (2.37-7.8%) and very high in straw (75-87.4%), confirming its role as a roughage with low energy value.
           
    Starch is particularly high in corn (67.44%), making it a major energy source. These results confirm the clear difference in composition between the two types of feed.

    Physicochemical quality of milk
     
    Samples were obtained from raw milk of healthy ewes with healthy-looking udders and no signs of redness, heat, or edema for each day of sampling. The milk samples were bright white with no unusual odor.
           
    The physicochemical characteristics of the milk are shown in Fig 1. The pH of the milk remained stable in both farms, ranging from 6.61 to 6.75, with no significant difference. The acidity of the milk ranged from 19.67°D to 24°D, with slightly higher values in the concentrate-fed system.

    Fig 1: Physicochemical characteristics of milk.


           
    Fat and protein content were significantly higher in the farm receiving a concentrate and straw-based ration compared to the pasture-only system. The milk dry matter content is also higher in farm 1 (15.88 to 19.44 g/L) than in farm 2 (13.82 to 17.04 g/L). The mineral content follows the same trend, with slightly higher values in the intensive system.
     
    Effect of diet on milk quality
     
    Statistical analysis (Table 3) shows that diet has no significant effect on pH (p>0.05). However, highly significant differences (p<0.0001) are observed for acidity, fat content, protein content, dry matter and mineral content. Ewes fed a concentrated ration produce milk richer in fat and protein than those raised on pasture.

    Table 3: Effect of diet on ewe’s milk quality.


           
    The results obtained show that the nutritional quality of the pasture varies significantly over the study period, with a progressive increase in dry matter and crude fiber, associated with a decrease in total nitrogen and digestibility. This evolution is mainly explained by the maturity stage of the plant species, where the transition from the vegetative to the senescent stage leads to increased tissue lignification and a decrease in the protein value of the forage. This result is consistent with the observations of Demarquilly (1987), who reported an increase in fiber with plant age. According to Boudechiche et al. (2010), the mineral content decreases with age. According to Demarquilly and Andrieu (1988), leaves contain more ash than stems and this concentration tends to decrease with the progression of development and the age of the plant. Compared to Salhi (2013) study on grass, the protein concentration is low.
           
    This decline in forage quality has direct repercussions on milk composition, particularly protein and fat content. Indeed, the data from this study show superior physicochemical values in milk from the system receiving concentrates compared to the system based solely on grazing. This difference can be attributed to the higher energy and nitrogen density of the supplemented rations, which promotes greater udder synthesis.
           
    The role of diet in modulating milk composition has been widely demonstrated. Bocquier and Caja (2001) showed that the energy level of the ration directly influences milk fat content. In our study, the higher fat values in the concentrate system confirm this relationship. Furthermore, the decrease in protein content observed in the pasture system may be linked to the decline in forage nitrogen content over time.
           
    The acidity and pH of the milk remained relatively stable between the two systems, indicating that the sanitary and hygienic conditions of milking were generally well controlled. These results are consistent with the values   reported for ewe’s milk under similar conditions (Mathieu, 1998; Benlahcen et al., 2013).
           
    The dry matter and mineral content of milk follow the same trend as the protein and lipid components, with higher values in the intensive system. This suggests better nutrient availability in the supplemented ration, allowing for more efficient synthesis of milk constituents. This finding is consistent with Gonzalo (2005), who emphasizes the importance of nutritional supplementation in influencing the variation of milk dry matter.
           
    The results concerning the pH of ewe’s milk fall within the ranges generally reported in recent literature (6.4–6.8), confirming the buffering effect exerted by phosphate, citrate and protein systems, particularly caseins. Recent studies show that this parameter remains relatively stable but can be influenced by diet and stage of lactation (Claeys et al., 2021; Park, 2021). The slight alkalinity observed in some samples could be related to a diet rich in green forage or to physiological variations in the animals.
           
    The higher titratable acidity of sheep’s milk compared to other species is consistent with its high dry matter and protein content. Recent studies confirm that sheep’s milk has a higher acidity due to its high concentration of caseins and minerals (Pulina et al., 2022). This characteristic gives sheep’s milk better technological suitability, particularly for cheesemaking.
           
    The observed fat content, close to or above 7%, is consistent with values reported in several recent studies. It is well established that the fat content is strongly influenced by diet, particularly the proportion of fiber and fatty acids in the ration (Nudda et al., 2020). Furthermore, the stage of lactation plays a crucial role, with a progressive increase in fat content towards the end of lactation, a phenomenon confirmed by numerous contemporary studies (Pulina et al., 2022; Lankri et al., 2024).
           
    Regarding protein, the high values recorded in this study exceed those generally reported, which could be attributed to genetic, nutritional, or environmental factors. Recent research highlights that the protein composition of sheep milk is particularly sensitive to feed quality and rearing conditions (Park, 2021; Claeys et al., 2021). The high protein content of sheep milk is a major asset for its nutritional and technological qualities.
           
    The observed total solids and ash content confirm the high nutritional density of sheep milk. Recent studies indicate that these parameters are generally higher than in cow and goat milk, due to the greater concentration of nutrients (Pulina et al., 2022). However, the variations observed between farms can be explained by differences in farming practices, particularly the type of feed and climatic conditions.
           
    Furthermore, the impact of nutritional supplements, particularly lipid intake, on milk composition has been widely demonstrated. Enriching the ration with fatty acids significantly alters the milk lipid profile, increasing the proportion of unsaturated fatty acids (Nudda et al., 2020). This phenomenon is of significant nutritional interest for human health.
           
    It is also important to note that the differences observed between the two systems cannot be attributed solely to diet. The stage of lactation constitutes an additional factor influencing milk composition, particularly the variation in butterfat and protein levels over time. Several factors, including breed, season, stage of lactation and litter size, significantly influence the milk quality of goats (Singh et al., 2026). The incorporation of feed additives in dairy animal nutrition plays an important role in improving milk production and overall performance (Ahmed et al., 2022). Furthermore, reducing the proportion of barley grain in ewe diets during the third stage of lactation did not adversely affect milk yield or its composition, representing an economically beneficial strategy through reduced feeding costs. In addition, supplementation with yeast in low-barley, high-fiber diets improved energy utilization efficiency, thereby enhancing the nutritional value of the ration (Almallah et al., 2021).
           
    Finally, although the literature confirms the importance of diet in milk composition (Nudda et al., 2021), the results of this study highlight that systems based solely on grazing exhibit greater variability, linked to the seasonal fluctuation in the availability and quality of forage resources.

    CONCLUSION

    Analysis of physicochemical parameters revealed that dairy ewe’s milk is a sought-after feed with high nutritional value (fat content, mineralsandprotein levels). The results showed a variation between the two farms with different feeding regimes. Milk from grass-based diets differed from milk from diets based on straw and concentrated feed. The diet affects the analyzed milk parameters. Despite the observed drought, the physicochemical quality of the milk from grazed grass remains acceptableandit is the most economical option. The fat and protein levels are above 4%. To improve the quality of the ewe’s milk, supplementation with concentrates is necessary. Further analyses would be desirable, such as those of fatty acids, amino acids, vitaminsa nd minerals, all comparing the results with those from other diets.

    ACKNOWLEDGEMENT

    The authors express their deep gratitude to the livestock farmers for their invaluable logistical support and technical assistance throughout the study, as well as to the dairy farmers for their cooperation and adaptability during the experimental period, their collaboration and dedication were essential to the success of this research project.
     
    Disclaimers
     
    The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
     
    Informed consent
     
    The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered to. No ethical approval was required as this is a characterization article of a potential animal feed ingredient.

    CONFLICT OF INTEREST

    The authors declare no conflict of interest.

    REFERENCES


    1. Ahmed, N.A., Vishwanath, B.G. and Rangesh, P. (2022). Evaluation of impact of chelated mineral mixture formulation supplementation on milk quantity and milk quality parameters in lactating dairy cows under field conditions. Asian Journal of Dairy and Food Research. 41(3): 272-277. doi: 10.18805/ajdfr.DR-1808.

    2. Almallah, O.D., Abdullah, M.N., Abbo, N.Y. and Hussien, N.G. (2021). Impact of yeast supplement to the rations contained different levels of barley grain in milk production and components of Awassi ewes. Asian Journal of Dairy and Food Research. 40(3): 295-298. doi: 10.18805/ajdfr.DR-221.

    3. Arbouche, H.S, Arbouche, Y., Arbouche, F. and Arbouche, R. (2008). Valeur nutritive de quelques variétés d’orge algériennes pour l’alimentation des ruminants. Recherche agronomique. 22. https://asjp.cerist.dz/en/article/46064.

    4. Barker, D., Chiavegato, M., Campbell, B. and Verhoff, K. (2025). Advances in Sustainable Sheep Pasture and Grazing. In: Sustainable Sheep Production Systems. Stubbings, [L, Phillips, K (eds)],  Burleigh Dodds Science Publishing. https://doi.org/10.19103/AS.2024.0147.13

    5. Belhadia, M., Saadoud, M., Yakhlef, H. and Bourbouze, A. (2009). La production laitière bovine en Algérie: Capacité de production et typologie des exploitations des plaines du Moyen Cheliff. Revue Nature et Technologie. 1: 54-62. https://asjp.cerist.dz/en/article/41188.

    6. Benlahcen, K., Mouloudi, F. and Kihal, M. (2013). Study of the microbiological and physicochemical quality of raw milk from cows exposed to environmental pollutants in the region of west Algeria. International Journal of Environmental Engineering Science and Technology Research. 1(9): 229-240. https://www.researchgate.net/profile/Kihal Mebrouk/publication/281450323_Study_of_the_microbiological_and_Physicochemical_quality_of_raw_milk_from_ cows_exposed_to_environmental_Pollutants_in _the_region_of_west_Algeria/links/55e83ed908aeb65 16262ff1f/Study-of-the-microbiological-and-Physicochemical -quality-of-raw-milk-from-cows-exposed-to environmental- Pollutants-in-the-region-of-west-Algeria.pdf.

    7. Bennato, F., Ianni, A., Florio, M., Grotta, L., Pomilio, F., Saletti, M.A.  and  Martino, G. (2022). Nutritional properties of milk from dairy ewes fed with a diet containing grape pomace. Foods. 11(13): 1878. https://doi.org/10.3390/foods11131878.

    8. Bocquier, F. and Caja, G. (2001). Production et composition du lait de brebis: Effets de l’alimentation. INRA Productions Animales. 14(2): 129-140. https://doi.org/10.20870/ productions-animales.2001.14.2.3734

    9. Bocquier, F., Guitard, J.P., Vacaresse, C., Van Quackebeke, E., Delmas, G., Guillouet, P., Lagriffoul, G., Morin, E. and Arranz, J.M. (1997). Estimation de la capacité d’ingestion et des phénomènes de substitution fourrage/concentré chez les brebis Lacaune conduites en lots. Rencontres Recherche Ruminants. 4: 75-78. https://agris.fao.org/ search/en/providers/122439/records/64775d2df 92238f9f1deeb4c.

    10. Boudechiche, L., Araba, A. and Touati, A. (2010). Effet du surpâturage sur la biodiversité, la productivité et la valeur nutritive des prairies au nord-est algérien. Rencontres Recherche Ruminants. 17: 63. https://journees3r.fr/textes3r/2010 0109-effet-du-surpaturage-sur-la-biodiversite-la-productivite -et-la-valeur-nutritive-des-prairies-au-nord-est-algerien/

    11. Caraba, I.V., Caraba, M.N. (2023). Effects of feeding management system on milk production and milk quality from sheep of the Turcana breed. Animals. 13(18): 2977. https:// doi.org/10.3390/ani13182977.

    12. Chibani, C., Chabaca, R. and Boulberhane, D. (2010). Fourrages algériens. 1. Compositions chimiques et modèles de prédiction de la valeur énergétique et azotée [Document technique, École nationale supérieure agronomique, Alger]. https://lrrd.cipav.org.co/lrrd22/8/chab22153.htm

    13. Claeys, W.L., Cardoen, S., Daube, G., De Block, J., Dewettinck, K., Dierick, K. and  Herman, L. (2021). Raw or heated cow milk consumption: Review of risks and benefits. Food Control, 120, 107591. https://doi.org/10.1016/j.foodcont. 2020.107591

    14. Demarquilly, C. (1987). Les fourrages secs: Récolte, traitement, utilisation. INRA, Paris. https://agris.fao.org/search/en/ providers/122621/records/647396be3ed73003714 ceb11.

    15. Demarquilly, C. and Andrieu, J. (1988). Les fourrages. In: Alimentation des bovins, ovins et caprins. INRA, Paris. pp 315-335. https:/ /hal.science/hal-02856328/.

    16. Gonzalo, C., Blanco, M., Linage, B., Beneitez, E., Martinez, A., Juarez, M. et al. (2005). Bulk tank milk quality of dairy sheep in Castilla-León region (Spain). Rencontres Recherche Ruminants. 12: 401. https://journees3r.fr/textes3r/2005 1021-qualite-physique-chimique-et-hygienique-du-lait- de-brebis-chez-les-troupeaux-du-bassin-de-castilla- leon-espagne/.

    17. Haenlein, G.F.W. (2002). Relationship of somatic cell counts in goat milk to mastitis and productivity. Small Ruminant Research. 45: 163-178. https://doi.org/10.1016/S0921- 4488(02)00097-7.

    18. Jarrige, R. (1988). Alimentation des bovins, ovinsetcaprins. INRA, Paris. https://hal.science/hal-02854912/

    19. Labioui, H., Elmoualdi, L., Benzakour, A., Elyachioui, M., Berny, E. and Ouhssine, M. (2009). Étude physicochimique et microbiologique de laits crus. Bulletin de la Société de Pharmacie de Bordeaux. 148: 7-16. https://www.socpharm bordeauxasso.fr/pdf/pdf-148/148-007-016.pdf.

    20. Lankri, E., Boudour, K., Belabdi, I., Bouhroum, N. and Aichouni, A. (2024). Effect of shelf life on physicochemical and biochemical parameters of camel milk. Asian Journal of Dairy and Food Research. 43(2): 361-367. doi: 10.18805/ajdfr.DRF-337.

    21. Mathieu, J. (1998). Initiation à la physicochimie du lait. Tec and Doc Lavoisier, Paris. https://agris.fao.org/search/en/providers/ 122439/records/6472298b77fd37171a73288b.

    22. Maurer, J. and Schaeren, W. (2007). Le lait de brebis : un aliment de haute valeur nutritive. Revue suisse d’agriculture. 39(4): 205-208. https://agris.fao.org/search/en/providers/ 122607/records/6472477453aa8c896304a754.

    23. Mierlita, D. (2022). Influence of feeding on different types of pasture on the fatty acid profile and health indices of goat milk. South African Journal of Animal Science. 52(5). https:/ /doi.org/10.4314/sajas.v52i5.08.

    24. Nudda, A., Battacone, G., Boe, R. and Pulina, G. (2020). Nutritional modulation of milk fatty acid composition in sheep. Small Ruminant Research. 190: 106148. https://doi.org/10. 1016/j.smallrumres.2020.106148.

    25. Nudda, A., Cannas, A. and Pulina, G. (2019). Nutritional approaches to improve the fatty acid profile of milk fat in sheep and goats. Options Méditerranéennes, Série A. 123: 73-82. https://om.ciheam.org/ressources/om/pdf/a123/0000 7862.pdf

    26. Nudda, A., Correddu, F., Cesarani, A., Pulina, G. and Battacone, G. (2021). Functional odd- and branched-chain fatty acids in sheep and goat milk and cheeses. Dairy. 2(1): 79-89. https://doi.org/10.3390/dairy2010008.

    27. Park, Y.W. (2021). Bioactive components in sheep milk. Small Ruminant Research. 200: 106377. https://doi.org/10. 1016/j.smallrumres.2021.106377.

    28. Pirisi, A., Piredda, G., Scintu, M. and Fois, N. (2001). Effect of feeding diets on quality characteristics of milk and cheese produced from Sardinian dairy ewes. Options Méditerranéennes, Série A. 46: 115119. https://om.ciheam.org/ressources/ om/pdf/a46/01600121.pdf.

    29. Pulina, G., Milán, M.J., Lavín, M.P., Theodoridis, A., Morin, E., Capote, J. and Caja, G. (2022). Invited review: current production trends, farm structures and economics of the dairy sheep and goat sectors. Journal of Dairy Science. 105(4): 2881-2904. https://doi.org/10.3168/jds.2021-21227.

    30. Sahraoui, H., Smili, H., Djouza, L. et al. (2024). Consommation du lait et produits laitiers caprins: Situation actuelle et perspectives. Journée scientifique nationale du GRAL. https://dspace.univ-ghardaia.edu.dz/xmlui/handle/ 123456789/9619.

    31. Salhi, H. (2013). Valeur nutritive des espèces spontanées de la plaine du moyen Chlef [Thèse de magistère, Université de Chlef]. http://dspace.univ-chlef.dz/handle/123456789/ 132.

    32. Salhi, H., Meziane, M., Noura, A., Ali-Benamara, B. and Bensaïd, A. (2019). Évaluation du potentiel fourrager des végétations de friche dans cinq localités de Chlef (Algérie). Fourrages. 237:  95-100. https://afpf-asso.fr/_objects/afpf_revues/ f237-salhi-3421.pdf.

    33. Singh, G., Sharma, R.B., Sharma, K., Kumar, A. and Sharma, L.K. (2026). Effect of environmental factors on goat milk and meat quality under field and farm rearing condition: A Review. Agricultural Reviews. 47(2): 275-281. doi: 10.18805/ag.R-2757.

    34. Taherti, M. and Kaidi, R. (2018). Productivité de la brebis Ouled Djellal selon le mode de conduite de la reproduction. Lebanese Science Journal. 19(1). https://lsj.cnrs.edu.lb/ wp-content/uploads/2018/04/LSJ-Mourad-Taherti.pdf

    35. Wang, B., Sun, H., Wang, D., Liu, H. and Liu, J. (2022). Constraints on the utilization of cereal straw in lactating dairy cows: A review from the perspective of systems biology. Animal Nutrition. 9: 240-248. https://doi.org/10.1016/j.aninu. 2022.01.002.
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