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 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.

The use of milk replacer instead of whole milk may be an economical alternative to calf-rearing systems. However, together with the volume fed, its composition is critical for high performance, especially regarding the origin of the protein. Two milk replacers with different protein content were evaluated to see the effect on the performance of calves. Thirtythree Holstein calves were distributed in the treatments: (1) High Volume and Low Protein (HV/LP), control group: 8 liters, 19.5% CP; (2) High volume and high protein (HV/HP): 8 liters, 23.7% CP and (3) Low Volume and High Protein (LV/HP): 6 liters, 23.7% CP. Calves were gradually weaned from the seventh week of life. Starter feed intake and fecal score were recorded daily. Weekly, calves were weighed, body measurements taken and blood samples were collected for metabolites analysis. Fecal score was lower (P>0.05) for animals in treatments HV/LP. Animals in treatments HV/HP had greater number of days in diarrhea (P<0.05) as compared to LV/HP fed calves. However LV/HP fed calves presented 66.7% mortality rate with a lower average age at death (P<0.05). There was no effect of treatments for body weight, average daily gain, body measurements and intake (P>0.05). Regarding blood metabolites, lactate concentration was higher (P<0.05) in animals fed HV/HP as compared to LV/HP and total protein concentration was lower (P<0.05) for calves fed HV/HP, while the other metabolic parameters did not differ. The use of substitutes with high vegetable protein content negatively affects the performance of calves and may increase mortality rates when low volumes are fed.

RESUMO Foram utilizados 24 bezerros que receberam 4L/dia de sucedâneo, além de livre acesso a água e concentrado até a 8a semana. Os animais foram distribuídos em delineamento de blocos casualizados, em dois tratamentos: 1) Controle: sem a suplementação de probiótico; 2) Suplementação de 2g/d de Bacillus subtilis e Bacillus licheniformis via sucedâneo lácteo. Semanalmente os animais foram pesados e foram aferidas as medidas corporais; também foram realizadas colheitas de sangue para determinação de glicose, proteína total, ureia e albumina, além de hematócrito. Foram colhidas amostras de fezes semanalmente para contagem de bactérias ácido láticas e enterobactérias e determinação de pH fecal. O peso corporal, o ganho de peso médio diário e as medidas corporais não foram alteradas pela suplementação; muito embora tenham apresentado efeito significativo de idade dos animais. O escore fecal, pH fecal e consumo de concentrado diário também não foram afetados pela suplementação. No entanto, o consumo de concentrado e o pH fecal sofreram influência da idade em resposta ao crescimento natural dos bezerros. A contagem de bactérias ácido láticas foi maior em número do que a contagem de enterobactérias durante todo o período. Apenas as enterobactérias sofreram efeito da idade, enquanto as bactérias ácido láticas permaneceram variando, porém dentro de um padrão constante. Os parâmetros sanguíneos também não foram afetados pela suplementação com probiótico mas todos, com a exceção da albumina, tiveram influência da idade. A suplementação com o probiótico não apresentou benefícios no desempenho ou no metabolismo de bezerros leiteiros, também não reduziu a ocorrência de casos de diarreia.

Regardless of the causative agent, diarrhea results in large loss of water and electrolytes, which leads to reduced performance and mortality. The aim of this study was to evaluate oral rehydration solutions in order to determine the most effective in restoring electrolytes and water while maintaining animal performance. Forty two calves (14 per treatment) were distributed in one of three treatments (1) Common electrolytes solution (dextrose, sodium bicarbonate and sodium chloride; 507±2 mOsm), (2) Glutellac ® (sodium acetate, glucose and sodium and potassium chloride; 665±1 mOsm); and (3) Common electrolytes solution + Aminogut ® (glutamate and glutamine; 575±2 mOsm). Treatments were administered when fecal score ≥3, in a scale of 1 to 5. During diarrhea daily water intake was registered and blood sample was taken for metabolites, electrolytes and gases determination. Animals did not differ in days in diarrhea, fecal score or hematocrit. Calves receiving Glutellac ® presented higher voluntary water intake. There was no effect of treatment for animal performance and starter feed intake. Concentrations of Na + and HCO 3 tended to be higher for animals rehydrated with Glutellac ®. While there was an increase in HCO 3 from the first to the second day, K + and glucose decreased. The increased voluntary water intake in animals rehydrated with Glutellac ® , which shows greater simplicity of use, are the main advantages of this solution.

This study aimed to evaluate the performance and metabolic changes in dairy calves fed in a step-up/step-down program and supplemented with lysine and methionine in a milk replacer (MR) or starter concentrate (SC). Male Holstein calves (n = 45) were blocked and distributed in the control without supplementation (1) and with lysine and methionine supplementation in the SC to achieve an intake of 17 and 5.3 g/d, respectively (2), and in the MR to achieve the same daily intake (3). MR was fed 4 L/d until the 2nd week, 8 L/d from the 3rd to 6th week, and 4 L/d from the 7th to 8th week, when calves were weaned. The calves were followed until the 10th week of age. Feed intake was measured daily. Weight and body measurements were registered weekly, and blood samples were collected biweekly. The lysine and methionine intake during the whole period was higher when supplementation occurred via MR. There was a supplementation effect for average daily gain after weaning, and the animals supplemented in the MR had lower BW than those that were not supplemented. Supplementation in MR decreased starter intake at the 10th week and total intake (g DM/d) after weaning. Supplementation with lysine and methionine in the MR or the SC did not benefit the performance or metabolism of dairy calves in the step-up/step-down program. Further studies are needed to understand the effects of amino acid supplementation on feed intake.

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