Effects of feeding unlimited amounts of milk replacer for the first 5 weeks of age on rumen and small intestinal growth and development in dairy calves

Abstract

The development of the gastrointestinal tract in newborn calves is essential for sufficient nutrient uptake. An intensive milk feeding during the neonatal period may impair the rumen development in calves. The aim of this study was to investigate effects of milk replacer (MR) feeding in unlimited amounts for the first 5 wk of age on the gastrointestinal growth and development in preruminant calves at wk 9 of age. Twenty-eight newborn Holstein and Holstein × Charolais crossbred calves (19 male and 9 female) were fed MR ad libitum (ADLIB) or in restricted amounts (6 L per day; RES) until wk 5 of age. Thereafter, the MR intake of ADLIB was gradually reduced at wk 6 and 7, and all calves received 6 L of MR per day until wk 9 of age. In wk 9, calves were slaughtered and carcass and organ weight as well as rumen papilla size in the atrium, ventral sac, and ventral blind sac, and villus size of the mucosa in the small intestine (duodenum; proximal, mid, and distal jejunum; and ileum) were determined. The expression of mRNA associated with the local insulin-like growth factor (IGF) system was measured in the rumen epithelium. Ad libitum MR feeding increased MR intake and growth in ADLIB without influencing concentrate intake compared with RES. Carcass weight in wk 9 was greater in ADLIB than in RES. The density of the rumen papillae in the atrium and ventral blind sac was greater in RES than in ADLIB calves, but surface area of the epithelium was not different between groups in the investigated regions of the rumen. The mRNA abundance of IGF1 in the atrium tended to be greater and the IGFR1 mRNA abundance in the ventral sac tended to be lower in the ADLIB than in the RES feeding group. The rumen pH and volatile fatty acid concentrations were not affected by MR feeding intensity. In mid-jejunum, villus circumference was greater in ADLIB than in RES calves. In the distal jejunum, villus surface area and the villus height/crypt depth ratio were greater and the villus circumference and height tended to be greater, whereas crypt depth was smaller in ADLIB than in RES calves. The findings from this study indicate that ad libitum MR feeding for 5 wk of age followed by its gradual reduction promotes growth performance without any negative influence on gastrointestinal growth and development in dairy calves at 9 wk of age.

Appropriate Dairy Calf Feeding from Birth to Weaning: “It’s an Investment for the Future”

“…Farmers mainly based weaning decisions on calf age, with some also considering calf bodyweight or starter intake, recognising that calves should be consuming over 1 kg/day of dry calf starter before weaning to indicate sufficient rumen development and prevent growth checks [1]. These practices should support gastrointestinal growth and development in dairy calves [65]. However, not all farmers provided calves with access to water from birth, which may negatively affect rumen development, restricting pre-weaning feed-efficiency and impeding growth both pre-and post-weaning [30].…”

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

“…The results demonstrated that intake of solid feed and weight gain increased during weaning in calves fed elevated amounts of milk and weaned through the step-down method compared with those fed milk conventionally. More recent studies (Schäff et al, 2016(Schäff et al, , 2018 have also used the "step-down" method by feeding MR (125 g of MR powder per L) ad libitum for 5 wk, followed by reduction in MR proportionally day by day to 6 L of MR at wk 7 compared with calves fed only 6 L until weaning to investigate growth, metabolic adaptation, health, and rumen and small intestinal growth. The benefits reported in this study were greater perirenal fat and muscle mass and increased anabolic metabolism (as indicated by increased insulin-like growth factor 1 concentration in blood) for step-down calves compared with those who had restricted amounts of milk.…”

Efeito da dieta liquida no desempenho e custo de produção de bezerros leiteiros na fase de cria

“…Boito et al 2015atribuíram esse efeito ao valor biológico do sucedâneo, que é menor que o do leite integral e apresenta uma menor taxa de absorção dos nutrientes quando comparados ao leite integral. Além de atributos nutricionais influenciarem no ganho de peso dos animais, outro fator determinante diz respeito às características organolépticas dos substitutos lácteos, o que dificulta a adaptação dos animais a essa dieta (França et al, 2011;Schäff et al, 2018).…”

“…Isso se deve ao fato de existirem diversas marcas de sucedâneo no comércio e com diferentes composições. Quando o substituto lácteo não comporta os níveis nutricionais adequados e não é utilizado corretamente, pode acarretar alguns problemas nutricionais e digestivos tendo como destaque: excesso de amido e de fibra, tipo e inadequada incorporação da gordura e utilização de fontes proteicas de baixo aproveitamento ou que provocam transtornos digestivos nos bezerros, além de deterioração gradual na integridade das vilosidades intestinais, em consequência de reações alérgicas (Schäff et al, 2018).…”