Effects of different liquid feeding strategies during the pre-weaning period on the performance and carcass characteristics of dairy bull calves

Effects of Milk Feeding Strategy and Acidification on Growth Performance, Metabolic Traits, Oxidative Stress, and Health of Holstein Calves

Effects of milk feeding strategy and acidification on calf growth, metabolic traits, oxidative stress, and health were evaluated in the first 78 days of life. Holstein calves (N = 48; 12 calves/treatment) were assigned to 1 of the 4 treatments in a 2 × 2 factorial arrangement of milk feeding strategy [6 L/d (MOD) or 12 L/d (HIGH) of milk] and acidification [non-acidified milk (NAM) or acidified milk (ACM)] on day 2. Calves were bucket-fed milk as follows: 6 L/d from days 2 to 49 for MOD and 6 L/d from days 2 to 49, 12 L/d from days 7 to 42, and 8 L/d from days 43 to 49 for HIGH calves. All calves were then fed 4 L/d from days 50 to 56. Starter and water were available ad libitum, while hay was fed at 5% of starter from day 64. Calves were weighed, measured, and blood (except days 14, 42 and 56) sampled on days 2, 14, 28, 42, 49, 56, 63 and 78. Data were analyzed using Mixed PROC of SAS with time as repeated measurements. Fecal scores, checked daily, were examined by the logistic regression using a binomial distribution in GLIMMIX procedure. There were no three-way interactions observed for all the parameters. We detected a milk feeding strategy × time interaction for starter intake, body weight, ADG, ADG/ME, FE, structural measurements, and glucose. Although, overall (558.0 vs. 638.6 g/d), HIGH calves tended to consume less starter compared to MOD, significant differences were only observed in week 8. The HIGH calves had greater ADG during days 2–14 (1.12 vs. 0.75 kg/d) and tended to have greater ADG on days 15–28 (0.79 vs. 0.55) and 29–42 (0.86 vs. 0.60) and lower on days 57–63 (0.11 vs. 0.38) compared to MOD calves. The HIGH calves had greater BW from days 28 to 78 compared to MOD, while NAM were bigger compared to ACM calves from days 49 to 78. The HIGH calves had lower overall feed and metabolizable energy efficiencies compared to MOD. Except for BW and heart girth, no milk acidification × time interaction was observed for starter intake, ADG, FE, or ADG/ME. Blood glucose in calves fed NAM-HIGH and ACM-HIGH were greater compared to those fed moderate milk volumes on day 28 only. Albeit, feeding strategy had no effect, calves fed ACM had lower likelihood of experiencing diarrhea (odds ratio = 1.32; 95% confidence interval: 1.018–1.698) compared to those fed NAM. Overall milk feeding strategy had no effect on growth, while milk acidification reduced growth in calves, despite lowering the likelihood of experiencing diarrhea.

Effects of rearing system and feeding intensity on the fattening performance and slaughter value of young crossbred bulls

The aim of this study was to determine the effects of rearing system and feeding intensity on the fattening performance and slaughter value of 38 young crossbred bull calves. The calves were raised naturally with nurse cows (NC) or were fed milk replacer (MF) until 150 days of age. During the rearing period the NC calves were healthier and had higher average daily gain (by 0.15 kg) compared to the MF calves. After a 30-day transition period, the animals were fattened in intensive (I) and semi-intensive (SI) systems from 181 to 560 days of age. During the fattening period, the bulls were fed ad libitum a total mixed ration (TMR) composed of grass silage and concentrate. The concentrate to silage ratio, on a DM basis, was 25:75 (SI) and 40:60 (I). The MF calves had lower BW at the end of the fattening period compared to the NC calves but the rearing system had no effects on daily gain during the fattening period. Compensatory growth was not observed during fattening. During the fattening period, a higher proportion of concentrate in the ration contributed to higher feed intake, higher feed efficiency and more desirable carcass characteristics. Three-rib cuts from the carcasses of the I bulls had significantly (P<0.05) higher fat content and lower bone content compared to the carcasses of the SI bulls. The longissimus thoracis muscle of the I bulls had higher (P<0.01) intramuscular fat content compared to the SI bulls.