Genetic relationships of clinical mastitis, cystic ovaries, and lameness with milk yield and somatic cell score in first-lactation Canadian Holsteins

Abstract

The objective of this study was to investigate the genetic relationships of the 3 most frequently reported dairy cattle diseases (clinical mastitis, cystic ovaries, and lameness) with test-day milk yield and somatic cell score (SCS) in first-lactation Canadian Holstein cows using random regression models. Health data recorded by producers were available from the National Dairy Cattle Health System in Canada. Disease traits were defined as binary traits (0=healthy, 1=affected) based on whether or not the cow had at least one disease case recorded within 305 d after calving. Mean frequencies of clinical mastitis, cystic ovaries, and lameness were 12.7, 8.2, and 9.1%, respectively. For genetic analyses, a Bayesian approach using Gibbs sampling was applied. Bivariate linear sire random regression model analyses were carried out between each of the 3 disease traits and test-day milk yield or SCS. Random regressions on second-degree Legendre polynomials were used to model the daily sire additive genetic and cow effects on test-day milk yield and SCS, whereas only the intercept term was fitted for disease traits. Estimated heritabilities were 0.03, 0.03, and 0.02 for clinical mastitis, cystic ovaries, and lameness, respectively. Average heritabilities for milk yield were between 0.41 and 0.49. Average heritabilities for SCS ranged from 0.10 to 0.12. The average genetic correlations between daily milk yield and clinical mastitis, cystic ovaries, and lameness were 0.40, 0.26, and 0.23, respectively; however, the last estimate was not statistically different from zero. Cows with a high genetic merit for milk yield during the lactation were more susceptible to clinical mastitis and cystic ovaries. Estimates of genetic correlations between daily milk yield and clinical mastitis were moderate throughout the lactation. The genetic correlations between daily milk yield and cystic ovaries were near zero at the beginning of lactation and were highest at mid and end lactation. The average genetic correlation between daily SCS and clinical mastitis was 0.59 and was consistent throughout the lactation. The average genetic correlation between daily SCS and cystic ovaries was near zero (-0.01), whereas a moderate, but nonsignificant, correlation of 0.27 was observed between SCS and lameness. Unfavorable genetic associations between milk yield and diseases imply that production and health traits should be considered simultaneously in genetic selection.

Genetic relationships among female fertility disorders, female fertility traits and productivity of Holstein dairy cows in the early lactation period

“…Also, Koeck et al. () found that cows with a high EBV for milk yield were more susceptible to OC, and estimated a genetic correlation of 0.26 between daily milk yield and OC. Garnsworthy et al.…”

Inferring causal relationships between reproductive and metabolic health disorders and production traits in first-lactation US Holsteins using recursive models

“…Dechow and Goodling (2008) reported that early culling was a reliable indicator of poor cow health. Several studies (Simianer et al, 1991;Rauw et al, 1998;Koeck et al, 2013b) have reported that an antagonistic relationship exists between milk production and disease resistance. Beaudeau et al (2000) reported that metabolic disorders have effects on milk production, reproductive performance, and culling.…”

Comparative study on production, reproduction and functional traits between Fleckvieh and Braunvieh cattle

“…In order to develop feasible total merit indices and to introduce new selection traits in the genetic improvement programmes, there is a need for up-to-date information on a wide range of relevant traits that have economical and animal welfare implications [1]. The main drawback on introducing functional traits into breeding programmes is the general low genetic additive variance, with heritability estimates of 0.02 to 0.09 for clinical mastitis [3], 0.01 to 0.07 for fertility-related diseases [4] and 0.02 to 0.04 for lameness [5]. …”