Developmental Changes in the Kinetics of Glucose and Urea in Holstein Calves

Abstract

Because weaning is the point when the nutrient composition of feed changes for the neonatal ruminant, the present experiment was conducted to assess the developmental changes in the kinetics of glucose and urea over this period, using stable isotopes of glucose and urea, at 4, 13, and 24 wk in calves. Plasma concentrations of nonesterified fatty acids, amino-N, urea-N, and insulin-like growth factor-I increased, but that of growth hormone decreased with age. The plasma glucose concentration increased at 13 wk of age and thereafter decreased at 24 wk of age. The glucose irreversible loss and recycling rates were significantly higher at 4 wk of age than at 13 and 24 wk of age. On the other hand, the irreversible loss and recycling rates of urea, as well as the urea pool size, were higher at 24 wk of age than at 4 and 13 wk. It is concluded that weaning at 6 wk is the pivotal time for the alteration of glucose kinetics. However, the aging process, but not weaning, is important for changes in the kinetics of urea in calves.

Increase in Crude Protein Content of Milk Replacers with Vegetable Protein: Effect on Health and Dairy Calves' Performance

“…Nitsan et al (1971) reported similar values of plasma urea to animals fed whole milk and that receiving milk replacer containing soybean. Hayashi et al (2006) obtained plasma urea concentration values in the fourth week after calves' birth of approximately 24 mg dL −1 , which coincides partly with the values obtained in the current study for treating LV/HP and HV/HP. Because this parameter is strongly influenced by the diet consumed, the behavior of the curve HV/LP treatment could be explained by the milk replacer lower protein content.…”

Effects of Na-butyrate supplementation in milk formula on plasma concentrations of GH and insulin, and on rumen papilla development in calves

“…RT-PCR for the expression of Sglt-1 mRNA was performed by random hexamer primers. The RT-PCR quantification was made with the Light Cycler System (Roche Molecular Biochemicals; Hayashi et al 2006). Glyceraldehyde-3-phosphate dehydrogenase was included in the assays as a housekeeping gene.…”

Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves

“…The weaning stress along with lower feed intake could be the reason for lower plasma glucose in both groups at this time period. Around weaning, the rates of irreversible loss and recycling of glucose decreased suggesting that glucose is preferably used as the energy source in suckling calves (Hayashi et al, 2006). Higher glucose levels in subsequent periods would suggest that calves in both groups were well adapted to the feeding regime and could have a better ability to utilize glucose.…”