The objective of this study was to determine whether addition of water to starter would improve performance, rumen fermentation parameters, blood metabolites, and behavior in dairy calves. For this purpose, 30 Holstein male calves (3 d of age; 42.0 ± 4.2 kg of body weight) were randomly assigned to 1 of the following 3 starter diets differing in moisture content: (1) 90% dry matter (DM), (2) 75% DM, and (3) 50% DM. Weaning and final body weight values were found to increase linearly with increasing dietary water. Moreover, starter intake increased linearly during the preweaning and overall periods. Average daily gain also increased linearly in calves receiving the 75% and 50% DM diets compared with those receiving the 90% DM diet. However, treatments had no effects on gain-to-feed ratio. Adding water to a starter with 50% DM led to linear increases in both total volatile fatty acids and molar proportions of acetate and propionate in the rumen but it had no effect on the molar proportions of butyrate, isovalerate, or valerate, nor did it have any effect on acetate-to-propionate ratio. Similarly, times spent on eating, ruminating, standing, lying, and nonnutritive oral behavior exhibited no differences across treatments. Finally, addition of water to the starter diet led to no significant changes in the concentrations of selected blood metabolites, respiration rate, or rectal temperature. Results indicate that calves readily accept wetter feeds with a DM content of 50% and that adding water to starter diets improves calf performance during the hot months of summer.

Heat stress is a major problem for dairy cows in hot climates, thus coping strategies are essential. This study evaluated the effects of increasing diet fermentability on intake, total tract digestibility, ruminal pH and volatile fatty acids (VFA) profile, blood metabolite profile and milk production and composition of lactating dairy cows managed under conditions of ambient heat stress. Nine multiparous cows (650 ± 56 kg BW; mean ± SD) averaging 102 ± 13 days in milk and producing 54 ± 6 kg/day were randomly assigned to a triplicate 3 × 3 Latin square. During each 21-day period, cows were offered one of three total mixed rations that varied in diet fermentability. The three levels of diet fermentability were achieved by increasing the proportion of pellets containing ground wheat and barley in the dietary DM from 11.7% (low), to 23.3% (moderate), and 35.0% (high) by replacing ground corn grain. Each period had 14 day of adaptation and 7 day of sampling. The ambient temperature–humidity index ( ≥ 72) indicated that the cows were in heat stress almost the entire duration of the study. Also, rectal temperature of cows was elevated at 39.2°C, another indication of heat stress. Increasing diet fermentability linearly decreased dry matter intake (22.8, 22.5, 21.8 kg/day for low, moderate and high, respectively; P ≤ 0.05) but increased non-fibre carbohydrate digestibility (P ≤ 0.05) and tended to increase digestibility of DM (P = 0.10) and crude protein (P = 0.06). As a result, the intake of digestible DM was not affected by the treatments. The production of 3.5% fat corrected milk (32.6, 33.7, and 31.5 kg/day) was quadratically (P ≤ 0.05) affected by diet fermentability with lower production for the high diet compared with the other two, which were similar. Rumen pH (ruminocentesis) and proportions of butyrate and isovalerate linearly decreased whereas propionate proportion linearly increased with increasing diet fermentability (P ≤ 0.05). The rumen concentration of NH3-N (11.0, 9.0, and 8.7 mg/dL) and blood concentration of urea linearly decreased with increasing diet fermentability (P ≤ 0.05). The activity of alkaline phosphatase increased (65.1, 83.2, and 84.9 U/l) and concentration of malondialdehyde decreased (2.39, 1.90 and 1.87 µmol/l) linearly with increasing diet fermentability (P ≤ 0.05), which indicated possible attenuation of the effects of oxidative stress with increasing diet fermentability. Overall, a modest increase of diet fermentability improved nitrogen metabolism, milk protein production and oxidative stress of heat-stressed dairy cows, but a further increase in diet fermentability decreased milk yield.

Very recently, we added water to a dry texturized starter diet and found substantial improvements in calf performance during summer, leading to the hypothesis that the wet starter diet would also benefit calf performance during winter. Forty-five 3-day-old male Holstein calves (BW 43.4±3.4 kg) were blocked by initial BW and distributed randomly to one of three starter diets (1 calf per pen; 15 pens per treatment) that differed only in moisture content as 90%, 75% and 50% dry matter (DM; DM90, DM75 and DM50, respectively). The starter diet comprised 55.1% ground ingredients (soybean meal, barley and corn gluten meal), 21.9% whole corn, 10% rolled barley and 10% chopped alfalfa hay. The mean ambient temperature averaged 2.1±0.9°C during the 70-day experiment. Calves were weaned at day 50 of the study. Although starter feed intake remained unaffected by treatment, the calves receiving DM75 and DM50 consumed more starter feed (DM basis) than those receiving DM90 diet during the first 20 days of the experiment. Body weight at weaning exhibited a quadratic response with the heaviest weaning weight (76.8 kg) occurring when calves consumed DM75 diet. Adding water to the dry starter diet tended to linearly increase final BW. Average daily gain during the pre- (0.67 kg/day) and post-weaning (1.22 kg/day) periods was the greatest for calves receiving DM75 and DM50, respectively. Although feed efficiency during the pre-weaning and overall periods did not differ across the treatments, a quadratic effect was detected in the post-weaning feed efficiency, with the lowest value being observed with DM75 diet. No difference was noted on skeletal growth parameters measured on days 50 and 70. Adding water to the dry starter diet linearly increased total volatile fatty acids concentration in the rumen. No difference among treatments existed in calf behavior recorded on days 35 and 70. As moisture content of the starter diet increased, the extent of sorting for long particles (>2 mm) and against fine particles (<0.125 mm) decreased. During the 70-day winter trial, adding water to the dry texturized starter diet with 10% chopped alfalfa hay resulted in a higher feed intake during the first weeks of life, a quadratic tendency toward improved growth rate during the pre-weaning period, and possibly a more functional rumen fermentation. A wet starter diet with 75% DM in the physical form offered in this study can be recommended to improve calf performance during winter.

No abstract

A growing body of evidence suggests health-promoting effects of kefir consumption on different nonruminant species, leading to the speculation that kefir may act as a probiotic and benefit calf performance and health. Our objectives were to determine effects of feeding kefir on performance and health of calves in the first 70d of life. Thirty 3-d-old female Holstein calves (body weight=38.2±3.1kg) were blocked by initial body weight and assigned randomly to 1 of 3 treatments (1 calf per pen; 10 pens per treatment). Kefir was added to whole milk (vol/vol) at 0:1 (control; KF0), 1:3 (KF1), or 1:1 (KF2) and fed twice per day (0800 and 1600h) from d3 through 45 and then once per day until weaning, which occurred on d50. Pre- and postweaning intake of starter, daily body weight gain, and gain-to-feed ratio exhibited no difference among treatments. Adding kefir to whole milk fed directly to calves had no effect on concentration of blood metabolites collected on d20, 40, and 70. Body length on d50 (weaning) and 70 was greater in kefir-fed calves. Kefir intake improved fecal scores and reduced days with diarrhea during the first 2wk of life. Apparent digestibility of organic matter, ether extract, crude protein, and neutral detergent fiber remained unaffected by treatment. Overall, it appears that directly feeding kefir to calves during the preweaning period did not improve the performance of calves under the conditions of the current study; however, its consumption marginally improved body length and fecal consistency in the first weeks of life, which is an important concern in intensive calf-rearing systems. Feeding kefir to neonatal calves may be a viable approach to improve the health of calves in commercial calf-rearing operations, although to validate its health-promoting effects additional research is needed to investigate its effects under different calf-rearing conditions.