Goats, which are widely raised and easily fed in worldwide, can capacity to convert low-quality pastures, heathlands and shrublands into milk, meat and other products. Goats demonstrating tolerance to malnutrition, excessive heat and diseases. This attribute enables goats to adapt to challenging environmental conditions (Günlü and Alaşahan, 2010; Atay and Gokdal, 2016; Ergül and Hızlı, 2023; Singh et al., 2025). Women also play an important role in goat farming, which supports the economic well-being of the family (Majumder et al., 2024). Goats, as farm animals, are bred for their meat, milk, hair, manure and many other products. Goat milk and meat, in particular, have a significant share in the livestock sector (Alaşahan and Öztürk, 2019). Türkiye has a goat population of 11,191,414 head, of which Hair goats constitute 98%. Goats contribute 1.6% of the country’s total milk production and 4.8% of total red meat production (TURKSTAT, 2025a, 2025b, 2025c). Hair goats possess aromatic meat, exhibit strong vitality and are resistant to both hot and cold climates as well as drought. They are distributed across nearly all regions of Türkiye and are well adapted to long distance movement. However, their rearing is more intensive in mountainous, hilly, forested, scrubland and rural pasture areas (Tekin and Arlı, 2019; Şirin, 2019; Garip and Arslan, 2021). Recent studies have focused on various aspects of goat production, including goat feeding and goat-derived products such as meat and milk, demonstrating the growing scientific interest in this field (Devatkal et al., 2025; Hamad et al., 2025; Khoi et al., 2025; Wulansari et al., 2026; Sittisang et al., 2026).
       
From both national and farm economic perspectives, it is essential that ruminant off spring complete their growth and development in a healthily. Once animals reach adulthood, numerous factors including productivity are influenced by feeding and management practices applied during the suckling and post weaning periods (Toprak and Pehlivan, 2020). In small ruminant production, the first three weeks of life, together with the feeding regimen applied from this period until weaning, represent the most critical phases for achieving profitable and sustainable livestock production (Gülşen, 2021). It is stated that kids and lambs should be adapted to concentrated feed after 6-7 days of age (Ermetin, 2021). Early introduction of dry feed is essential to support rumen development and the establishment of microbial populations in lambs and kids (Oral et al., 2021). The effect of starter feeds is important because they initiate rumen development and complete deficiencies during the milk feeding stage (Gülşen, 2021). Concentrated feeds accelerate rumen development and provide high concentrations of volatile fatty acids necessary for papillae development (Rico-Costilla et al., 2024). One study indicated that feeding concentrated feed to kids from 7 days of age increased rumen papillae length and improved rumen morphology (Htoo et al., 2018). It has also been noted that one of the developmental differences in kids is the failure to transition to a period of adapting them to intensive and roughage feeding from the 10^th day onwards (Kandemir et al., 2018). Rumen development is crucial for successful weaning and a optimal growth rates after weaning. Since kids meet their nutritional needs from dry feed after weaning, sufficient solid feed consumption is necessary to ensure rumen development before weaning (Htoo et al., 2018).
       
This study aims to compare the growth performance of Hair goat kids based on the age at which they were introduced to starter feed within the scope of the “Genetic Improvement Project of Hair Goat in Farmer Conditions Edirne Province” conducted in Edirne province, Türkiye.

Animals
 
This study was conducted using the data of the “Genetic Improvement Project of Hair Goat in Farmer Conditions Edirne Province” which was carried out in Edirne province within the scope of the “National Genetic Improvement Project of Animal in Farmer Conditions” implemented across Türkiye under the coordination of the General Directorate of Agricultural Research and Policies (TAGEM) of the Ministry of Agriculture and Forestry. Within the scope of the project, all weighings and records were kept by the breeders. These records were checked by the project technical staff. In this study, differences in birth weight (BW), 60-day and 90-day weights and average daily weight gain (ADG) were determined in kids that were introduced to starter feed at two different ages (15 and 30 days) in farms included in the breeding project. The study includes data from 464 kids recorded in 2025. Two groups were formed from the farms included in the project: Goat kids introduced to starter feed at 15 days of age (G1; n=136 males and 136 females) and other goat kids introduced at 30 days of age (G2; n=96 males and 96 females). Farms were classified into either the G1 or G2 group according to their routine starter feeding introduction protocol (15 or 30 days of age). The feeding groups were determined by each farm’s existing management practice. The study included single kids born to 3-year-old dams, raised under grazing conditions and provided free access to starter feed (concentrate feed) and roughage. During sampling, care was taken to ensure that the feeding and management practices of the breeders were similar. Priority was given to single kids that suckled their dams, grazed on the same pastures with their dams and consumed water, concentrate feed and roughage ad libitum after grazing. The main difference between the two groups was that some breeders initiated the concentrate feed adaptation period 15 days earlier. Because all farms were located in the same province and geographic region, goat kids were exposed to comparable climatic conditions and grazing environments, thus minimizing the potential impact of environmental factors.
       
The live weights (LW) of kids were corrected for 60 and 90 days of age using the following formulas (Mellado et al., 2016).

 

Average daily weight gain (ADG) on day 90: (90^th day live weight-Birth weight)/90

 
Statistical analyses
 
Data were presented as mean and standard deviation. In this study, the independent samples t-test was used in the SPSS statistical package program (IBM, version 20) to determine the difference between groups. The significance level is p<0.05.

In this study, BW, weight at 60 and 90 days of age and ADG of hair goat kids were presented in Table 1. The results showed a significant difference in BW between the two groups of kids. The mean BW of the G2 group (2.78±0.51 kg) was higher than that of the G1 group (2.52±0.46 kg) (p<0.001). Studies conducted in the provinces of Tokat, Konya, Kahramanmaraş, Antalya, Osmaniye and Karaman report that the average BW of single kids ranges from 2.82 to 3.68 kg (Tekin and Öğeç, 2017; Tekin and Arlı, 2019; Elmaz et al., 2020; Güngör et al., 2021; Ergül and Hızlı, 2023; Şirin, 2023). According to our findings, the BW of kids in Edirne were lower than the average BW reported in previous studies. Compared to the studies mentioned above, the lower results observed in this study may be attributed to several factors, including regional environmental conditions, the nutritional status of pregnant goats, pasture quality, variations in breeding and management practices, genetic differences and implementation of selection programs (Alaşahan and Öztürk, 2019; Şirin 2023; Ergül and Hızlı, 2023).


       
When the 60-day weights of the kids were examined, the G2 group (14.58±0.90 kg) was found to have significantly higher weights compared to the G1 group (13.89±0.93 kg) (p<0.001). However, this difference disappeared by day 90 and no significant difference was determined between the two groups (p>0.05). According to the results of the present study, kids that were introduced to starter feed at an earlier age exhibited higher growth rates and improved performance by day 90. At day 90, the G1 group (191.86±12.24 g/day) showed a significantly higher increase in ADG than the G2 group (186.88±15.31 g/day) (p<0.001).
       
Previous studies conducted in Türkiye reported that the average 90 day weight of single Hair goat kids ranged between 16.33 kg and 18.81 kg (Elmaz et al., 2020; Güngör et al., 2021; Ergül and Hızlı, 2023). The findings of these studies were lower than those obtained in the present study. However, one study reported a 90 day weight of 21.78 kg, which is higher than the findings of our study (Şirin, 2023). Regarding ADG, our findings were lower than the values reported in some previous studies, while were higher than others. According to previous studies, the ADG of single Hair goat kids has been reported as 145.53 g (Güngör et al., 2021), 148.5 g (Tekin and Öğeç, 2017), 160.9 g (Tekin and Arlı, 2019), 168.16 g (Ergül and Hızlı, 2023) and 211.9 g (Şirin, 2023). In other studies, Hayes et al., (2019) reported an ADG of 113.80 g in meat goat kids fed creep feed, while Alaşahan and Öztürk (2019) reported ADG values of 144 g and 137 g for Hamdani and Hair goat kids, respectively, during the 90 day period. In a study conducted on Single Boer kids, the average ADG was determined as 102.9 g in those consuming creep feed (Htoo et al., 2015). The variations in 90-day weight and ADG observed in this study compared to the existing literature can be attributed to factors such as pasture quality, the quality of concentrate and roughage, management practices, genotypes, weighing day for ADG calculation and the implementation of selection programs (Tekin and Öğeç 2017; Alaşahan and Öztürk, 2019; Şirin 2023; Ergül and Hızlı, 2023).
       
Numerous studies have reported the initiation of concentrate feeding at an early age offers advantages in terms of body and carcass weight gain in animals (Bhatt et al., 2009; de Melo et al., 2017;  Liu et al., 2022). In one of these studies, lambs that began concentrate feeding on day 7 had higher carcass weights after day 56 and higher body weights between days 77-84 compared with lambs that began concentrate feeding on day 42 (Liu et al., 2022). It has been reported that lambs receiving concentrate feed supplementation can be weaned at an earlier age and that those provided concentrate feed reach weight of 18 kg approximately 13 days earlier than lambs not given concentrate feed (de Melo et al., 2017). In another study, it was reported that early concentrate feeding combined with limited ewe-lamb contact supported rumen development and increased total volatile fatty acid concentrations in the rumen (Wang et al., 2019). Bhatt et al., (2009) reported that lambs receiving concentrate feed exhibited higher weaning weights and ADG. Moreover, several studies have demonstrated that the early initiation of concentrate feed intake enhances ADG (Fernandes et al., 2012; Silva et al., 2014; Brand and Brundyn, 2015).
       
However, there are also studies that indicate the opposite regarding early initiation of concentrated. One study reported that kids introduced to concentrate feed at 30 days of age exhibited higher pre weaning ADG than those that did not consume concentrate feed; nevertheless, the concentrate fed kids did not achieve a higher financial return (Hayes et al., 2019). One study reported that goat kids fed only milk replacer achieved higher carcass weights than those that also received starter feed (Rico-Costilla et al., 2024). Another study reported that providing goat kids with starter feed in addition to their dam’s milk from 18 days of age had no significant effect on pre-weaning live weight gain (Yıldırır et al., 2010).
       
Late and short-term introduction of concentrate feed may not result in a statistically significant improvement in the body weight of kids. In our study, the advantage of initiating concentrate feeding earlier became evident by day 90, resulting in comparable final live weights between the groups. The higher ADG observed on day 90 in kids that began consuming concentrate feed on day 15 suggests that early supplementation enhances growth performance (p<0.001), likely due to increased feed intake associated with greater LW at later stages.

The findings of the present study indicate that initiating concentrate feeding 15 d earlier was associated with a higher ADG (p<0.001) during the suckling period. Although kids in the early-fed group (G1) had significantly lower birth weights than those in G2, this difference was compensated for by day 90, with no significant difference in live weight observed between groups (p>0.05). These results suggest that early concentrate introduction promotes compensatory growth in Hair goat kids. However, given that feed intake and associated cost data were not evaluated in this study, the economic feasibility of early concentrate introduction should be assessed in future research. Furthermore, including rumen development markers, body condition score, or health-related parameters in future research will provide a better understanding of the compensatory growth observed in kids accustomed to early concentrated feeding.

One limitation of this study is that starter feed intake and feeding costs were not recorded. Therefore, an economic evaluation of early starter feeding could not be performed. Future studies should incorporate feed intake and feed cost recording, together with carcass yield and market price data, to enable a comprehensive economic evaluation of early starter feed introduction in Hair goat kids. All farms were located within the same province and were therefore exposed to broadly similar climatic and pasture conditions. But farm-level management practices (e.g., herd health protocols, grazing management, caretaker experience) could not be fully standardized across farms. Farm-related management effects cannot be entirely excluded as a potential confounding factor.

This study includes farm data from the “Genetic Improvement Project of Hair Goat in Farmer Conditions Edirne Province” (Project number: TAGEM/22KIL2022-01), which is supported by the “National Genetic Improvement Project of Animal in Farmer Conditions” conducted by the Ministry of Agriculture and Forestry, General Directorate of Agricultural Research and Policies (TAGEM). We would like to thank the Ministry of Agriculture and Forestry and TAGEM for granting us permission to use the farm data. We also thank the Edirne Province Sheep and Goat Breeders’ Association and the project’s technical staff for their contributions to the study.
 
Authorship
 
Conceptualization: HT, SK, Investigation: HT, SK, Methodology: HT, SK, Formal Analysis: HT, SK, Writing-original draft: HT, SK, Writing-review and editing: HT, SK.
 
Artificial intelligence statement
 
During the preparation of this work the authors used [ChatGPT, Copilot, Paperpal, Claude and DeepL] in order to [proofreading and to improve the fluency of the manuscript]. After using this tool/service, the authors reviewed and edited the content as needed and takes full responsibility for the content of the published article.
 
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.

The authors declare that there are no conflicts of interest regarding the publication of this article.