Genetic correlations between milk production and health and fertility depending on herd environment.

High milk production in dairy cattle can have negative side effects on health and fertility traits. This paper explores the genetic relationship of milk yield with health and fertility depending on herd environment. A total of 71,720 lactations from heifers calving in 1997 to 1999 in the Netherlands were analyzed. Herd environment was described by 4 principal components: intensity, average fertility, farm size, and relative performance indicating whether herds had good (poor) health and fertility despite a high (low) production. Fertility was evaluated by days to first service and number of inseminations (NINS); somatic cell score was used as a measure of udder health. Data were analyzed with a multitrait reaction norm model. Genetic correlation within traits across environments ranged from 0.84 to unity. Genetic correlations of the 3 traits with milk yield were antagonistic but varied over environments. Genetic correlation of milk yield with days to first service varied from 0.30 in small herds to 0.48 in herds with low average fertility. Correlations with NINS varied from 0.18 in large herds to 0.64 in high fertility herds, and with somatic cell score from 0.25 in herds with a high fertility relative to production to 0.47 in herds with a relative low fertility. Selection in environments of average value resulted in different predicted responses over environments. For example, selection for a decrease of NINS of 0.1 in an average production environment decreased milk yield by 35 kg in low production herds, but by 178 kg in high production herds.

[1]  I. Misztal,et al.  Genetic components of days open under heat stress. , 2004, Journal of dairy science.

[2]  G. Pollott,et al.  Genotype x environment interactions and genetic parameters for fecal egg count and production traits of Merino sheep. , 2004, Journal of animal science.

[3]  M. Kirkpatrick,et al.  A quantitative genetic model for growth, shape, reaction norms, and other infinite-dimensional characters , 1989, Journal of mathematical biology.

[4]  M. Wiltbank,et al.  Fertilization and early embryonic development in heifers and lactating cows in summer and lactating and dry cows in winter. , 2002, Journal of dairy science.

[5]  M. Calus,et al.  The association between somatic cell count patterns and milk production prior to mastitis , 2005 .

[6]  B. Engel,et al.  Joint Estimation of Breeding Values and Heterogeneous Variances of Large Data Files , 1996 .

[7]  P Sandoe,et al.  Staying good while playing god--the ethics of breeding farm animals. , 1999, Animal welfare.

[8]  N. Wray,et al.  Assigning pedigree beef performance records to contemporary groups taking account of within-herd calving patterns , 1997 .

[9]  D. Falconer,et al.  Introduction to Quantitative Genetics. , 1962 .

[10]  M. Calus,et al.  Estimation of environmental sensitivity of genetic merit for milk production traits using a random regression model. , 2003, Journal of dairy science.

[11]  R. Blake,et al.  Genotype by environment interaction for yield and somatic cell score with alternative environmental definitions. , 2003, Journal of dairy science.

[12]  U. Emanuelson,et al.  Genetic and Environmental Correlations Among Female Fertility Traits and Milk Production in Different Parities of Swedish Red and White Dairy Cattle , 2001 .

[13]  M. Calus,et al.  Genotype x environment interaction for protein yield in Dutch dairy cattle as quantified by different models. , 2002, Journal of dairy science.

[14]  P. Garnsworthy,et al.  Fertility in the high-producing dairy cow ☆ , 2004 .

[15]  F. H. Dodd,et al.  Control of mastitis in the dairy herd by hygiene and management. , 1969, Journal of dairy science.

[16]  M. Goddard,et al.  Genotype x environment interaction for milk production of daughters of Australian dairy sires from test-day records. , 2003, Journal of dairy science.

[17]  G. Shook,et al.  An optimum transformation for somatic cell concentration in milk. , 1980 .

[18]  M. Calus,et al.  Effects of data structure on the estimation of covariance functions to describe genotype by environment interactions in a reaction norm model , 2004, Genetics Selection Evolution.

[19]  W. G. Hill,et al.  Heritability of milk yield and composition at different levels and variability of production , 1983 .

[20]  S. Stearns,et al.  The effects of phenotypic plasticity on genetic correlations. , 1991, Trends in ecology & evolution.

[21]  W. G. Hill,et al.  Genetic aspects of common health disorders and measures of fertility in Holstein Friesian dairy cattle , 1997 .

[22]  R. Veerkamp,et al.  Covariance functions across herd production levels for test day records on milk, fat, and protein yields. , 1998, Journal of dairy science.

[23]  E. Noordhuizen-Stassen,et al.  Undesirable side effects of selection for high production efficiency in farm animals: a review , 1998 .

[24]  R. Veerkamp,et al.  Estimation of genotype×environment interactions, in a grass-based system, for milk yield, body condition score, and body weight using random regression models , 2003 .

[25]  M P L Calus,et al.  Influence of herd environment on health and fertility and their relationship with milk production. , 2005, Journal of dairy science.

[26]  J. Jensen,et al.  Genotype by Environment Interaction in Nordic Dairy Cattle Studied Using Reaction Norms , 2002 .

[27]  M. Calus,et al.  Associations among descriptors of herd management and phenotypic and genetic levels of health and fertility. , 2005, Journal of dairy science.

[28]  H. Barkema,et al.  Management practices associated with the incidence rate of clinical mastitis. , 1999, Journal of dairy science.

[29]  H. Koelewijn,et al.  Selection on reaction norms, genetic correlations and constraints. , 1994, Genetical research.

[30]  M. Wiltbank,et al.  Relationship between level of milk production and estrous behavior of lactating dairy cows. , 2004, Animal reproduction science.