Effect of Weaning and Natural Suckling on the Colostrum, Milk and Dry Matter Intake and Growth Performance of Sahiwal Calves

The successful calf rearing is the key to success of dairy farm enterprise because these young calves are the future replacement stock. In traditional system of management of cow calves in India, they are allowed to suckle their dams for their milk feeding as well as for the let-down of milk. In most of the intensive dairy farming it is necessary to remove the calf from the dam immediately or shortly after the parturition and rear the calf on whole milk or milk replacers substituted using milk pail (Bucket or nipple) but in cow which is a social animals with strong maternal instinct, their calves and dam relationships are closely bonded, and the cow calves become more stress when separated from the dam (Foulkes, 2005). Therefore they do not consume needed amount of colostrum (Smijisha 2007), depriving the immunoglobulin during early post-natal period resulting in higher morbidity and mortality.

The artificial rearing or weaning of calves has been found to be adversely affecting the growth and health of calves (Singh et al., 2019) due to large number of factors particularly in tropics. In weaning system of rearing calves can show a distinctive distress response both when they are separated from the cow, and later when they are weaned from milk. Keeping the aforesaid in view present study was planned to investigate the effect of weaning and natural suckling on the colostrum intake, milk intake, total dry matter intake and growth performance of Sahiwal calves.

The present study was conducted at the Livestock Research Centre, ICAR-National Dairy Research Institute, Karnal (Haryana) in year 2017. National Dairy Research Institute is located at an altitude of 250 meters above mean sea level, latitude and longitude being 29042" N and 77054" E respectively. The calves were divided into two homogeneous groups on the basis of age and body weight and named as weaned Group (n=6) and suckled Group (n=6). The experimental period was of 180 days from birth of calves. Suckling group calves were allowed to suckle from the dam (own mother) twice a day before/after milking from birth to 90 days of age. Weaning group calves were weaned immediately after birth (calves do not suckled from mother/dam) and termed as non-suckling group. Each calf in Suckled group was fed with colostrum of its own dam within few hours after birth and twice daily for first 5 days of age and later that was allowed to suckle its dam twice daily before/after milking. The non-suckling calves were fed as per standard protocol followed at NDRI as presented in Table 1, 2 and 3.



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Parameters recorded
 
Body weight (kg)
 
The birth weight of calves was recorded at the time birth and after that the body weight of calves was recorded regularly at fortnightly intervals by the use of electronic weighting machine.
 
Colostrum intake (kg)
 
To calculate the colostrum intake in naturally suckled group of calves, calves were weighed before and after colostrum feeding and in case of the weaned group of calves weighed amount of colostrum was offered and the residual was measured to calculate the colostrum intake in weaned group.
 
Milk intake (kg/day)
 
Milk intake of natural suckled calves
 
Milk intake of the calves in the suckling group recorded once in a week. The complete milking was done on the seventh day without allowing the calves to suckle. However, the calves were allowed to suckle their dams at the start of milking just for the let-down of milk. The milk intake by the calves were calculated by deducting the average daily milk yield of the cow on other 6 days of the week from the milk yield on the 7thday when the calves were not allowed to suckle their dams.
 
Milk intake of weaned calves
 
The weaned calves were offered a weighted amount of milk as per their feeding schedule and the residual was measured to calculate the actual milk intake in Table 2.
 
Dry matter intake (kg/day)
 
Total dry matter intake (DMI) for weaned and suckled group was calculated at fortnightly intervals by taking into account the daily average amount of roughage and concentrate mixture consumed in Table 1.
 
Statistical analysis
 
All the data obtained were categorized according to the objectives of the study and were analysed with the help of statistical software SPSS (version. 17). The significance of effects of treatments on the different dependent variables was analysed using analysis of variance (ANOVA) procedure and the differences between the means were compared using Tuckey post-hoc test.
 
Ethical approval
 
For the present study, the plan of experiment was approved by Institutional Animal Ethics Committee for animal experiments and the ethical guidelines of the National Dairy Research Institute, Karnal (Haryana) were followed during all the animal experimentations

Daily colostrum Intake
 
In the present study, the overall means of daily intake of colostrum up to 5 days after birth in weaned and suckled groups of Sahiwal calves were 2.42±0.10 and 2.65±0.08 kg/day respectively which are presented in Table 4. There was no significant difference between weaned and suckled groups in the overall daily intake of colostrum, however, the mean intake of colostrum from 1^st to 3^rd day of birth was significantly (P<0.05) higher in suckled than the weaned groups of calves. On the subsequent days (4^th and 5^thday), mean daily colostrum intake in both the group was almost similar. Daily intake of colostrum during first 3 days was lesser in weaned calves because calves did not have any experience of drinking colostrum from pail. However, after the 3 days of colostrum feeding, weaned calves might get learned to drink colostrum from pail which could explain the non-significant difference in the amount of colostrum intake in both groups of calves from fourth to fifth day after birth. The almost similar finding has been reported by Kumar and Kamboj (2014) who described that the average colostrum intake for first 2 days was significantly higher in suckled buffalo calves as compared to weaned calves whereas overall mean milk intake was 2.79±0.08 and 2.61±0.01 kg in suckled and weaned group of buffalo calves respectively, which did not differ significantly. Stafford et al., (2005) had also reported that majority of the calves become efficient drinkers within 48 hours of birth while small number of slow feeders may need individual feeding at least up to 4 days after birth.


 
Milk intake (kg/day) by calves
 
The mean ± SE of milk intake by the experimental Sahiwal calves are depicted in Table 5. The overall mean for intake of milk by calves up to 16th week of age was 2.80±0.06 and 3.37±0.06 kg/day in weaned and suckled group of Sahiwal calves respectively. The mean daily milk intake was significantly (P<0.01) higher in suckled calves as compared to weaned group of calves. This difference in daily milk intake might be due to better digestion of milk due to more mixing of salivary enzymes with milk and also due to realization of natural drinking behaviour under suckling system. The results obtained in the present study are in agreement with the finding of Singh et al., (2019) who revealed that the mean squares value of milk intake from sixth day after birth to 12 weeks of age in suckled calves were significantly higher (P<0.01) as compared to weaned buffalo calves. Mendoza et al., (2010) who reported that Holstein calves managed under restricted suckling system (7.2 kg/day) had a higher (p<0.001) average milk intake than calves under artificial rearing (5.4 kg/day). Similarly, Boonbrahm et al., (2004c) indicated that 16.3% more milk was consumed by restricted suckled calves as compared to bucket reared calves. A significant higher average milk intake in suckled buffalo calves (4.26 kg/day) in comparison to weaned calves (3.05 kg/day) has been shown by Singh and Kamboj (2015). However, no significant difference between the milk intake of the calves under restricted suckling and artificial rearing has been reported in Holstein x Zebu calves by Hernandez et al., (2006) and in buffalo calves by Kumar and Kamboj (2014).


 
Total dry matter intake (from milk, green fodder and concentrate) (kg/day) by Sahiwal calves
 
The average of total dry matter intake (from milk, green fodder and concentrate) by experimental Sahiwal calves is presented in Table 6. The overall means of total dry matter intake was 1.30±0.17 and 1.42±0.18 kg/calf/day in weaned and suckled groups of calves respectively. There was no significant difference in value of total dry matter intake of weaned and suckled group of calves. In agreement with the present findings, Froberg et al., (2008) also reported similar total intake of metabolisable energy from milk and concentrate in the restricted suckled (1051 MJ) and artificially reared calves (1092 MJ). Findings of present study was further corroborated by the findings of Kumar and Kamboj (2014) and Singh and Kamboj (2015) who also did not find any significant difference between average total dry matter intake of weaned and suckled group of buffalo calves. Contrary to this, Bharti et al., (2015) reported that the overall average daily dry matter intake in buffalo calves suckled up to 90 days after birth was significantly (P<0.01) higher (0.873 ± 0.01 kg) than weaned at birth (0.759±0.01kg) and calves suckled up to 45 days after birth (0.791±0.00 kg) and stated that the higher DMI in suckling than weaned calves might be due to more dependency on milk in suckled calves being milk the principal feed  whereas, Azim et al., (2011) reported significantly higher DMI in late weaned calves than early weaned buffalo calves.


 
Body weight (Kg) of calves
 
The mean ± SE of body weights of Sahiwal calves in weaned and suckled groups at birth and then at fortnightly intervals up to 12 fortnights are presented in Table 7. The average birth weights of weaned and suckled groups of calves were (20.6±0.6 and 21.3±1.2 kg) which did not differ significantly between both the groups. The mean final body weights at 12^th fortnight were 88.7±4.4 and 96.9±3.3 kg in weaned and suckled groups respectively which was numerically higher in suckled group of calves as compared to weaned group of calves. Findings of present study are on similar lines with the findings of Mendoza et al., (2010) who reported that the restricted suckled calves had a higher body weight at weaning (84.3 vs. 73.3 kg) than artificial reared calves. Sanh et al., (1997) reported that the body weight at 6 months of age was higher for restricted suckled calves (109 kg) than for artificial reared calves (105 kg). Roth et al., (2009) found that in dual purpose dairy cattle the sucked calves gained significantly more weight during the milk feeding period than the bucket fed calves (138.9±5.6 vs. 117.0 ± 2.6 kg). Further, Bharti et al., (2015) reported that the final body weight at 3 month of age in buffalo calves suckled up to 90 days after birth was significantly (P<0.01) higher (79.71 kg) than weaned at birth (69.51 kg) and calves suckled up to 45 days after birth (73.59 kg).


 
Average daily gain (kg) (ADG)
 
The average daily gain in body weight recorded at fortnightly intervals in weaned and suckled groups are presented in Table 8. The overall average daily gain (ADG) was significantly (P<0.01) higher in case of suckled calves than weaned group of Sahiwal calves. The overall mean ± SE of ADG of Sahiwal calves were 0.377±0.009 and 0.419±0.012 kg/day in weaned and suckled group of calves respectively. High weight gain in suckled calves is mainly ascribed to higher fat content in the residual milk, but it can also be related to differences in milk intake (Sanh et al., 1997; Mejia et al., 1998) and the associated improved health conditions of the calves (Yilma et al., 2006). Further, calves allowed to suckle had a higher level of oxytocin compared to bucket-fed calves (Lupoli et al., 2001). Froberg et al., (2008) also observed that the milk suckled by restricted suckling calves contained more fat and metabolisable energy (ME) per kg than the parlour milk fed to artificially reared calves (6.1% vs. 4.2% and 3.5 MJ/kg vs. 2.9 MJ/kg). Boonbrahm et al., (2004c) found that the energy intake from milk and the total ration respectively in the bucket reared (BR) group was 50% and 38% lower in AR group of calves than in the restricted suckling (RS) group of calves. In addition, suckled group of calves spent more time for milk feeding which may have resulted in the more secretion of saliva, better mixing of the milk with digestive enzymes resulting in to better utilization of colostrum as well as milk resulting in improved daily weight gain. The present finding are in agreement with those reported by Singh et al., (2019) who found body weight gain was significantly (P<0.01) higher in suckled buffalo calves as compared to weaned calves. Mendoza et al., (2010) reported that the restricted suckled calves gained more body weight (0.813 vs. 0.656 kg/day) as compared artificial reared calves. Sanh et al., (1997) reported that average daily weight gain from birth to 6 months for restricted suckled calves (445 g/day) was higher than for artificial reared calves (422 g/ day). Higher average daily body weight gain in suckled calves as compared to artificially reared calves has been also observed in several previous studies in calves (Boonbrahm et al., 2004a; Gonzalez et al., 1984) and in buffalo calves (Kumar and Kamboj, 2014; Bharti et al., 2015, Singh et al., 2019). In contrast to the present findings, Sikka et al., (2002) and Schoonmaker et al., (2004) did not find any significant effect on total body weight gain in suckling versus non-suckling buffalo calves (from birth to 3 months).

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From the findings of this study it could be concluded that the colostrum and milk intake performance as well as the final body weight and daily body weight gain was better in naturally suckled Sahiwal calves as compared to weaned calves and therefore, calf management practices should include natural suckling system particular in indigenous breeds.

All authors declare that they have no conflict of interest.