Differences between primiparous and multiparous dairy cows in the inter-relationships between metabolic traits, milk yield and body condition score in the periparturient period

D.C Wathes,Z Cheng,N Bourne,V.J Taylor,M.P Coffey,S Brotherstone

doi:10.1016/j.domaniend.2006.05.004

Abstract

During the early postpartum period dairy cows mobilize fat and muscle to support lactation. This is associated with alterations in blood metabolite and hormone profiles which in turn influence milk yield and fertility. This study developed models to determine how metabolic traits, milk yield and body condition score were inter-related at different times in the periparturient period and to compare these relationships in primiparous (PP, n = 188) and multiparous (MP, n = 312) cows. Data from four previous studies which included information on blood metabolic parameters, parity, milk yield, body condition score and diet were collated into a single dataset. Coefficients of polynomial equations were calculated for each trait between −1 week pre-calving and week +7 postpartum using residual maximum likelihood modelling. The completed dataset was used in a multiple correlation model to determine how the best fit curves were related to each other over time. PP cows had higher concentrations of insulin-like growth factor-I and lower β-hydroxybutyrate concentrations throughout, higher leptin concentrations pre-partum and both the peak in non-esterified fatty acids and the nadir in urea concentration occurred earlier after calving. These differences were associated with significantly lower milk production. Leptin concentrations fell at calving and were related to body condition score. Insulin was negatively correlated with yield in MP cows only. In MP cows the relationship between insulin-like growth factor-I and yield switched from negative to positive between weeks +4 and +7. Both β-hydroxybutyrate and urea were positively related to yield in PP cows. In contrast, in MP cows β-hydroxybutyrate was negatively correlated with yield and urea was strongly related to body condition score but not yield. These results suggest that there are differences in the control of tissue mobilization between PP and MP cows which may promote nutrient partitioning into growth as well as milk during the first lactation.

Highlights

The Holstein breed has been selected to produce high yields through a greater propensity for losing body condition to support milk production in early lactation and to target nutrients preferentially to the mammary gland
Least square mean (LSM) phenotypic values for each trait over the 8-week period from −1 week pre-calving until week +7 of lactation are presented in Figs. 1 (MY and body condition score (BCS)), 2 (IGF-I, insulin and leptin) and 3 (NEFA, BHB and urea)
The large dataset on metabolic changes in dairy cows during the periparturient period available for this study has enabled us to model how the inter-relationships between different metabolic traits alter over time, to study their relationship to milk yield and body condition, and to determine how these factors differed according to the parity of the cows

Summary

Introduction

The Holstein breed has been selected to produce high yields through a greater propensity for losing body condition to support milk production in early lactation and to target nutrients preferentially to the mammary gland. Non-esterified fatty acids (NEFA) released from lipid stores are either taken up by the udder to provide milk triglycerides or are oxidized in the liver as an alternative energy source. ␤-Hydroxybutyrate (BHB) is the predominant form of ketone body in blood and its concentration is as an index of fatty acid oxidation. Blood urea in both late pregnant and early lactating ruminants may rise following mobilisation of amino acids stored in skeletal muscle [3] or in circumstances where dietary protein supply exceeds energy availability [6,7]

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