This study investigates the newborn thermoregulatory responses to cold and the performance of calves fed different colostrum volumes. Thirty newborn Holstein calves were blocked by birth body weight (BW; 39.4 ± 6.5 kg) and fed different high-quality colostrum volumes: 10%, 15%, or 20% of BW, which was split and fed at 2 and 8 h after birth. At 24 h of life, calves were placed in a chamber at 10 °C for 150 min. Skin and rectal temperature (RT), heart and respiratory rate, and shivering were measured every 15 min. Blood samples were taken every 30 min. After the cold challenge, calves were housed in ambient temperature (26.8 ± 5.9 °C), with free access to water and concentrate and received 6 L/d of milk replacer. Feed intake, fecal score, and RT were recorded daily, until 56 d of age. Blood samples, BW, and body measures were taken weekly. During the cold challenge, prescapular temperature and total serum protein were greater for calves fed 15% or 20%. Leukocytes increased preweaning, presenting higher values for calves fed 20%. Even though there was a benefit for the calf submitted to cold stress on the first day of life, feeding higher volumes of colostrum resulted in no differences in performance during the preweaning phase. Nevertheless, calves fed a higher volume of colostrum (20% BW) presented increased immune responses during the preweaning phase.

This study aimed to evaluate performance, gut health and metabolic changes in dairy calves receiving milk replacer supplemented with lysine and methionine with 0.6% or 1% AminoGut (10% Glutamate and 10% Glutamine). Forty-five Holstein calves were blocked and distributed in the treatments: (1) Control: no supplementation; (2) Lys, Met, AminoGut 0.6%; (3) Lys, Met, AminoGut 1%. Animals were individually housed, with free access to water and concentrate. Milk replacer (6 L/d) was fed until the eighth week of life. Feed intake and faecal score were monitored daily. Calves were weighted and measured weekly. Blood samples were collected every other week to determine metabolites. Supplementation did not affect the performance nor the metabolism of calves. There was no effect of supplementation for faecal score. An age effect was observed for most of the variables, mainly as a response of starter intake and consequent shift from a pre to a functional ruminant metabolism. The supplementation of the milk replacer with lysine and methionine in association with 0.6% or 1% AminoGut had no effect on performance, gut health nor metabolism of dairy calves. More important than the fine adjustment of amino acid requirements is the adoption of practices to improve starter intake.

This study aimed to evaluate the performance and metabolic changes in dairy calves supplemented with lysine and methionine in milk replacer (MR) or starter concentrate (SC). Male Holstein calves (n = 45) were blocked and distributed in Control without supplementation (1) and; Lysine and Methionine supplementation to achieve an intake of 17 and 5.3 g/d in the SC (2) and to achieve of 17 and 5.3 g/d in the MR (3). MR was fed (6 L/d) until the 8th week of life when weaning occurred. Calves were followed until the 10th week of age. Feed intake was measured daily. Weight and body measurements were registered weekly. Blood samples were collected biweekly to evaluate the intermediate metabolism. The AA supplementation resulted in lower body weight at weaning and week 10. Calves fed SC Lys:Met had lower SC intake and lower total feed intake at weaning when compared to control. Calves fed control had higher heart girth, hip-width, and plasma glucose concentration. The supplementation with Lys and Met did not benefit dairy calves’ performance nor metabolism in this study. Supplementation through the MR was more efficient than SC to result in adequate daily intakes of AA. Further studies are needed to understand the negative effects of AA on calf starter intake.

Due to the synepitheliochorial placental structure, bovines show no maternal antibody flow from mother to fetus during pregnancy, resulting in an agammaglobulemic newborn

The objective of this study was to evaluate the effect of milk acidification in tropical climate conditions on dairy calves’ growth, health and selected blood metabolites. Thirty-two Holstein calves were blocked according to sex, birth date and weight, and distributed to the following...