Effects of different milk feeding levels and frequencies on performance of Holstein heifers during weaning and first lactation.

In the present study, the effects of milk feeding amount and feeding frequency (FF) on performance, blood metabolites, rumen fermentation, and performance of dairy heifers during the first artificial insemination (AI) and first lactation were investigated. The treatment group consisted of 48 female Holstein heifer calves (12/treatment) distributed in a 2 × 2 factorial arrangement with milk feeding [high = 8 L/d, HL or medium = 6 L/d, ML] and feeding frequency [2 × or 3 ×]. All calves were fed on a step-up/step-down method, weaned from milk at 56 d of age, and observed until 70 d of age. Heifer calves were kept uniform from 70 d of age until the first lactation to evaluate the long-term effects of the treatments. We observed no FF effect and no interaction between the level and FF on feed intake, average daily gain (ADG), feed efficiency (FE), body weight (BW), structural growth, blood metabolites, and rumen fermentation parameters. Calves fed HL milk had higher total dry matter intake (DMI), BW, and ADG during the pre- and post-weaning periods. During the preweaning period, HL-fed calves had higher serum insulin (trend) and glucose concentrations compared to ML-fed calves. Lower age at first AI was observed in calves fed HL rather than ML regardless of FF. Weight at first AI, milk yield (305 d), and energy-corrected milk (ECM-305 d) in the first lactation showed a trend toward higher values in HL-fed calves compared to ML-fed calves. Preweaning performance and calf maturity can be positively affected by feeding high amounts of milk at both FF.

Effects of freestall vs. bedded pack housing on growth performance, health status, and behavioral responses of weaned heifers.

This research evaluates the effect of two housing types, freestalls vs. bedded-pack, on growth performance, health scoring, and behavior of weaned heifers. Twenty-four heifers with no previous experience with freestalls (12 heifers/ treatment) were randomly assigned to the two treatments (freestalls vs. bedded-pack) at d 80 ± 3 of age. Heifers had free access to total mixed ration (TMR) and water throughout the experiment. The TMR intake and health score were recorded daily from d 80 to 110 of age. Body weight and skeletal growth of heifers were measured at the beginning (d 80) and the end (d110) of the experiment. Feeding behaviors were recorded for a period of 22 h and at the same time. Growth performance (ADG, structural growth, and final body weight), overall DMI, and health assessment (fecal score, general appearance, and rectal temperature) were similar between treatments. Behavioral patterns of eating, drinking, standing, lying, and rumination were also similar between treatments. However, in freestall-housed heifers, the proportion of time spent lying inside the stall increased by 8.1%, and time spent lying outside the stall decreased by 9.44% from the beginning to the end of the study (from 80 to 110 d). In summary, our results indicate that weaned heifers showed similar growth performance, behavior, and health when housed in freestall and bedded-pack housing. However, introducing weaned heifers to freestall housing at an early age will prepare them for using the facility.

Effects of group housing and incremental hay supplementation in calf starters at different ages on growth performance, behavior, and health.

The present study examined the effects of age at group housing and age at incremental hay supplementation in calf starters from 7.5 to 15% (dry matter, DM) and their interaction on growth performance, behavior, health of dairy calves, and development of heifers through first breeding. A total of 64 calves (n = 16 calves/treatment, 8 male and 8 female) were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement, with age at group housing (early = d 28 ± 2, EG vs. late = d 70 ± 2, LG; 4 calves per group) and age at incremental hay supplementation of calf starters from 7.5 to 15% of DM (early = d 42 ± 2 d, EH vs. late = d 77 ± 2, LH) as the main factors. All calves (female and male) were weaned at 63 days of age and observed until 90 days of age. Heifer calves were managed uniformly from 90 days of age until first calving to evaluate the long-term effects of treatment. No interactions were observed between age at group housing and age at incremental hay to calves on starter feed intake, performance, calf health and behavior, and heifer development through first breeding, which was contrary to our hypothesis. The age at which incremental hay supplementation was administered had no effect on starter feed intake, growth performance, or heifer development until first calving. When EG calves were compared with LG calves, nutrient intake (starter, total dry matter, metabolizable energy, neutral detergent fiber, starch, and crude protein), average daily gain, and final body weight increased. In addition, frequency of standing decreased and time and frequency of eating increased in EG calves compared to LG calves. Overall, early group housing leads to improved growth performance in dairy calves with no negative effects on calf health compared to late group housing.