Effects of milk replacer feeding strategies on performance, ruminal development, and metabolism of dairy calves

Abstract

Performance, rumen development, and metabolism of male Holstein calves (n=54) were evaluated according to 1 of 3 liquid feeding strategies: 4 L of milk replacer (MR)/d until 60 d old (4 L-60 d), 6L of MR/d until 29 d old and 4 L/d from 30 to 60 d (6L-29 d/4 L-60 d), or 6L of MR/day until 60 d old (60 d-6L). Water and starter were provided ad libitum. Intakes of MR and starter were monitored daily and body weight (BW) weekly. Blood samples for glucose and insulin concentrations and ruminal content samples for volatile fatty acids and ruminal ammonia concentrations were collected at 15, 30, 45, 60, 75, and 90 d of age. Six calves on each treatment were euthanized at 30, 60, and 90 d of age. Empty weights of forestomach and abomasum, papillae length, and mitotic index were measured. Average MR intake/d (expressed as a percent of BW) was greater for calves receiving 6L/d than for those receiving 4 L/d until 30 d of age. Calves on the 6 L-29 d/4 L-60 d had the smallest MR intake from 30 to 60 d old, followed by the 4 L-60 d and 6L-60 d treatments. Starter intake (kg of dry matter/day) did not differ between groups. It increased from 0.065 kg/d in the first month to 0.386 kg/d in the second month, and to 2.065 kg/d after weaning. Weight gain was greater for calves fed more MR in the first month, but no difference was observed during the second month. After weaning, 6L-60 d calves had greater rate of weight gain than others and were heavier at 30, 60, and 90 d of age. Weight of empty forestomachs, ruminal pH, and ammoniac nitrogen concentration were not different among groups. Propionate concentration was lower for 6 L-60 d calves, but acetate and butyrate concentrations were not influenced by MR feeding strategy. Calves fed more MR until d 30 had greater ruminal epithelium mitotic index. The different MR feeding strategies did not influence papillae length or ruminal epithelium thickness. Lesions such as ruminal parakeratosis or hyperkeratosis were not observed. The MR feeding strategy did not affect glucose concentration, but insulin was higher in 6L-60 d calves than in the other groups. Glucose concentration increased with age, whereas insulin decreased until 45 d old, and then started to increase until 90 d. In conclusion, MR feeding strategy did not influence ruminal development. Feeding calves 6 L of MR/d over 60 d resulted in greater rate of weight gain without negative effects on starter intake or forestomach development. The weight advantage that 6L-60 d calves obtained preweaning was maintained until 90 d of age.

Estudo longitudinal da infecção por enteropatógenos em bezerros neonatos, com diarreia, sob diferentes estratégias de aleitamento

“…Segundo Silper et al (2014), o consumo médio no primeiro mês de vida de bezerros foi inferior no grupo que recebeu 4 litros de leite/dia em relação ao grupo em que foi oferecido 6 litros/dia. O volume tradicionalmente utilizado, equivalente a 10% do peso do bezerro, fornece nutrientes apenas para mantença e ganho de peso de no máximo 300g/dia em condições termoneutras (Drackley 2008), sendo, portanto, insuficientes para ganhos esperados de 600-700g/dia nas criações intensivas de bezerros em condições climáticas, na maioria dos casos, fora da zona de conforto.…”

“…em nenhuma amostra de fezes de ambos os grupos. Apesar da ração dos bezerros apresentar coccidiostático em sua composição, o consumo de ração durante as duas primeiras semanas é baixo (Silper et al 2014) não sendo suficiente para fornecer a dose correta do coccidiostático. A Eimeria é um importante agente causador de diarreia em bezerros, os períodos pré-patentes das principais espécies de Eimeria variam de 6-11 dias para E. alabamensis até 15-20 dias para E. bovis e E. zuernii, espécies mais frequentes causando diarreia em bezerros.…”

“…Deficiências nutricionais estão relacionadas à depressão simultânea de vários mecanismos de defesa do sistema imune, como diminuição da concentração de IgA e da liberação de citocinas como IL-1, IL-6 e TNF-α, além do comprometimento dos mecanismos antioxidantes. Com a imaturidade do sistema imunológico dos bezerros neonatos e maior susceptibilidade a doenças, a nutrição adequada em bezerros pode ter efeitos positivos sobre a resposta imune e, consequentemente, melhorar a resposta às doenças neste período de vida (Woodward 1998, Nonnecke et al 2003, Silper et al 2014.…”

Perfil sanguíneo e peso de órgãos internos de bezerros leiteiros criados em diferentes sistemas de aleitamento

“…Da mesma forma, Khan et al (2007) observaram animais em aleitamento intensivo com concentrações de glicose superiores aos mantidos em aleitamento convencional. Já Silper et al (2014) não verificaram diferenças entre os teores de glicose sanguínea entre animais em sistema intensivo, fracionado ou convencional de aleitamento.…”

Invited Review: Nutritional regulation of gut function in dairy calves: From colostrum to weaning

“…Elevated milk feeding programs allow dairy calves to be fed ad libitum or often at 20% of their birth BW, which is greater than 8 L/d at a typical solids concentration of 12 to 13% or 1.2 kg of MR per day . In contrast, conventional feeding programs usually limit milk consumption to around 10% of birth BW, which is roughly 4 to 5 L/d at a typical solids concentration of 12 to 13% (Khan et al, 2007a,b;Silper et al, 2014). It is thought that by decreasing milk intake, starter intake will increase, thus leading to enhanced rumen development (Tamate et al, 1962).…”