Rumen Development, Intestinal Growth and Hepatic Metabolism In The Pre- and Postweaning Ruminant

Abstract

Both the role of intestinal development and the process of transitioning calves from their neonatal reliance on nutrients supplied from milk to nutrients supplied from grain are of substantial economic importance to the producer. Improvements to the calf nutritional regime can decrease mortality and disease susceptibility, increase postweaning rate of gain, ultimately enhancing the rate of herd genetic improvement (due to increased capacity for voluntary culling). Current feeding practices including daily encouragement to eat grain diets result in weaning from milk by 3 to 4 wk of age. Although the mechanisms are not yet completely understood, development of a viable fermentation within the rumen is required to initiate the maturation of the rumen epithelia. This transition results in tremendous metabolic ramifications to calf growth rate, as tissues must convert from reliance on glucose supplied from milk to the metabolism of short-chain fatty acids as primary energy substrates. This maturation is the result of differential expression of numerous genes regulating both physical and metabolic characteristics of the tissue. While the most dramatic physical changes occurring during development are associated with the rumen epithelium, changes in intestinal mass and metabolism are also realized in response to dietary changes. Amino acid use by the intestinal tissues is high and may affect amino acid availability in support of growth. Moreover, because the metabolic and protein synthetic activities of the digestive tract are high, accounting for up to 30% of both whole animal energy

Performance, rumen development, and carcass traits of male calves fed starter concentrate with crude glycerin

“…Because the DMI was greater due to the addition of crude glycerin, the calves could be weaned earlier, which would result in lower feeding costs because concentrate is cheaper than milk or dried milk and also stimulates rumen development and contributes to supplying nutrients to animals (Baldwin et al, 2004;Suárez et al, 2006;Khan et al, 2007). Considering the intake of 700 g day −1 concentrate (Quigley III, 1996;Campos and Lizieire, 2000) to carry out weaning, the calves that received concentrate with 240, 160, 80, and 0 g kg −1 crude glycerin included could have been weaned at 40, 42, 44, and 46 days of age, respectively (Figure 1).…”

Effects of kefir as a probiotic source on the performance of goat kids

“…It has been indicated that solid feeds in particular concentrates are crucial for the development of the rumen of neonatal ruminants. Based on various reports Baldwin et al (2004) pointed out that neonatal ruminants fed solely on milk diets, display limited rumen development in terms of rumen weight, capacity and papilla growth during the initial months of life. In this study, late adaptation to concentrate feed and the relation between milk and concentrate feed intake can be explained by a mechanism "reticular groove" proposed by Ørskov et al (1970).…”

Desempenho de bezerros alimentados com dietas líquidas à base de leite integral ou soro de leite

“…A chegada de grande quantidade de aminoácidos e gorduras ao intestino delgado pode gerar, por exemplo, um pico de somatostatina, resultando em inibição da secreção de hormônios e enzimas gastrintestinais e pancreáticas. Além disso, a somatostatina possui efeitos antiproliferativos, podendo retardar o desenvolvimento funcional da mucosa intestinal (Baldwin et al, 2004).…”