Hemoconcentration differs in neonatal dairy calves: Considerations for assessment of transfer of passive immunity.

Assessing transfer of passive immunity (TPI) is a critical management strategy to evaluate colostrum management and feeding; however, variability in hemoconcentration or serum or plasma volume in calves might influence TPI assessment. The objectives of this study were to (1) describe the variability in hemoconcentration as well as TPI in Holstein calves in New York State and (2) describe the effect of adjusting total protein (TP) for the degree of hemoconcentration by applying a sample average proportion of plasma in blood (PP) on TPI assessment. Records of TP and PP from 703 Holstein calves 1 to 9 d of age from 19 commercial dairy farms were analyzed.

Pre- and postpartum metabolizable protein supply: I. Effects on feed intake, lactation performance, and metabolic markers in transition dairy cows.

The objective of this study was to investigate the effect of increasing MP supply in the prepartum, postpartum, or both diets on intake, performance, and metabolic indicators. Multiparous Holstein cows (n = 96) were assigned to 1 of 4 treatment groups at 28 d before expected calving following a randomized block design. Prepartum diets were formulated to contain either a control (CON; 85 g of MP/kg DM) or high (HI; 113 g of MP/kg DM) level of estimated MP.

Pre- and postpartum metabolizable protein supply: II. Effects on plasma amino acids and markers of tissue mobilization in transition Holstein dairy cows.

The influence of diet composition on the degree of adipose and lean muscle mobilization and concentrations of circulating AA has been demonstrated during the transition period. Altering the MP supply might offer a strategy to control tissue mobilization and increase circulating AA availability, but the optimum supply of MP fed pre- and postpartum remains unknown. We investigated the effect of increasing the MP supply in the prepartum, postpartum, or both diets on plasma AA concentrations and ultrasound and circulating indicators of tissue mobilization.

Urinary and fecal potassium excretion prediction in dairy cattle: A meta-analytic approach.

Quantification of potassium (K) excretion in dairy cattle is important to understand the environmental impact of dairy farming. To improve and monitor the environmental impact of dairy cows, there is a need for a simple, inexpensive, and less laborious method to quantify K excretion on dairy farms. The adoption of empirical mathematical models has been shown to be a promising tool to address this issue.

Effect of close-up metabolizable protein supply on colostrum yield, composition, and immunoglobulin G concentration and associations with prepartum metabolic indicators of Holstein cows.

The prepartum diet as well as individual metabolic status of the cow influences colostrum parameters. The objectives of this study were to (1) investigate the effect of increasing prepartum dietary MP supply on colostrum yield, composition, and IgG concentration, and (2) identify prepartum metabolic indicators associated with these outcomes. Multiparous Holstein cows (n = 96) were blocked by expected calving date and randomly assigned to 1 of 2 prepartum diets formulated to contain a control (85 g of MP/kg of DM; 1,175 g of MP/d) or high (HI; 113 g of MP/kg DM; 1,603 g of MP/d) level of MP starting at 28 d before expected calving.