Rearing of young calves is a labor intensive and costly segment of livestock production. From birth to weaning, young calf undergoes a transition from monogastric to adult ruminant. The concept of weaning from milk at an early age is based on early development of functional rumen enabling calves to utilize low quality roughages. In current study, a series of experiments were conducted to refine the more effective weaning regime for buffalo calves and use of by-products of the ethanol production industry in early weaned cattle calves.
Conventionally, buffalo calves are kept with the dam, allowed to suckle a little amount of milk along with seasonal green forages, and weaned around the age of one year. To date, limited published work was available on growth performance and economics of buffalo calves weaned from milk at an early age. Therefore, the experiment was conducted to reduce the weaning age and evaluate the growth performance of male Nili-Ravi buffalo calves. Twenty-four male buffalo calves were assigned to one of the three treatments: continuous milk feeding (CMF), limited milk feeding (LMF), and early weaning (EW). After colostrum feeding, calves were individually fed whole milk at 10% of their BW, adjusted weekly until 6 wk of age. Thereafter, milk allowance was gradually tapered to zero in CMF, LMF and EW treatments at 12, 10 and 8 wk of age, respectively. Calf starter feed was provided ad libitum from wk 2 through wk 12 and individual intakes were recorded daily. Blood sampling was carried out form wk 6 through 12, on a weekly basis. The BW and structural measurements (HG, WH, and HW) were carried out at the start of experiment and later on a weekly basis. In young buffalo calves, the regimen of weaning at 8 weeks of age was more effective. The early weaned calves showed similar growth rate to those in the CMF and LMF by consuming more calf starter and saving a substantial amount of high priced milk. On the basis of the results of this experiment, buffalo calves successfully adapted to early weaning that might help to mitigate issues like poor growth and low returns associated with traditional calf rearing practices. Furthermore, this study effectively reduced the weaning age from 1 year to 8 weeks of age. Hence, reducing weaning age did not affect the growth performance of Nili-Ravi buffalo calves by 12 weeks of age.
Early development of the rumen is the main objective of a successful early weaning program which depends upon the amount of starter intake, VFA production, and ruminal papillae development. Studies have shown that grains in starter feed can be replaced by DDGS up to 28% of DM without compromising the growth performance and rumen development. Second experiment was planned to evaluate the effects of replacing grains and soybean with DDGS and ammonia treated DDGS at 25% of DM. Study was conducted in collaboration with dairy science department SDSU (USA). Twenty one neonatal male Holstein calves were assigned to one of the three of dietary treatments: C = 0% DDGS, DDGS = 25% DDGS, CAFEX-DDGS = 25% CAFEX treated DDGS. In a 10 week experiment, calves were fed 680 g MR through 4 week, reduced to half during wk 5, and weaned at the end of wk 5. Starter intakes were conducted daily; whereas, body weights, structural measurements were conducted at the start of experiment and then on a weekly basis. Jugular blood samples were taken on a weekly basis using EDTA and NaFl coated evacuated tubes. Rumen samples were collected from a subset of 15 calves (n=5 calves/ treatment) at wk 5, 7 and 10. At the end of experiment, four calves from each treatment were also slaughtered to determine rumen morphometric measurements (PL, PW, RWT and PC). Experiment illustrated that weight gain, structural measurements, total starter intake, DMI and feed efficiency were not affected by the inclusion of DDGS and CAFEX treated DDGS at 25% of DM in starter feeds. CAFEX treatment of DDGS improved the CP contents of DDGS from 29.5% to 40%; however, inclusion of CAFEX-DDGS in starter reduced feed intake during the pre-weaning period. Whereas, overall starter intake was higher in calves fed DDGS based starter feed indicating the effect of ammonia treatment on palatability. Lower pre-weaning starter intake, slow rumen fermentation of CAFEX-DDGS resulted in lesser BHBA concentration leading to lesser development of rumen papillae growth (PL and PW). However, there was a tendency for higher weight gain in calves fed DDGS based starter due to increase in starter intake. In the light of these results it is concluded CAFEX-DDGS can be included in starter feeds at 25% of DM without affecting the growth performance. However, further research is required to evaluate the digestibility of DDGS after CAFEX treatement. Similar, growth performance indicates that CAFEX-DDGS can replace the corn and soybean meal in starter feeds.
In third experiment, microbial diversity in developing rumen and intestine of young calves fed DDGS and CAFEX treated DDGS at 25% of starter was investigated. Experiement was carried out at SDSU dairy research station (USA). Fifteen calves with n=5 per treatment, fed according to protocols described in Experiment II. Calves were sampled for rumen contents at wk 5, 7 and 10 of age; whereas, intestinal contents were collected at the time of slaughter. The DNA was extracted subjected to PCR-DGGE and dendogram was constructed using cluster analysis software. Results revealed that microbial population was highly different from each other at wk 10 indicating the effect of age and dietary treatment on rumen micro flora. Whereas, intestinal and rumen bacterial diversity at wk 5 and 7 of age was not affected by inclusion of DDGS and CAFEX-DDGS in starter feed. The changes in intestinal microflora of DDGS and CAFEX-DDGS fed calves compared with control group showed that the effect of dietary treatments on post-ruminal availability of nutrients and microbial proteins. In conclusion, rumen bacterial population changes with the advancing age and the type of ingredients used in the diet. Further, research is required to identify the effect of feeding DDGS on growth of particular bacteria like methanogen and their impact on methane production and feed efficiency.