Heifer Fertility and Its Relationship with Cow Fertility and Production Traits in Holstein Dairy Cattle

Abstract

Breeding receipts from three AI units were merged with Ontario Dairy Herd Improvement Corporation and Record of Performance production records. Data comprised 53,705 heifer, 41,253 lactation 1, 14,688 lactation 2, and 3054 lactation 3 records by daughters of 2150 sires represented in 15,877 herd-year-seasons of birth. Three measures of heifer fertility, three measures of cow fertility, and three measures of production were investigated. Measures of heifer fertility were ages at first and last breeding and number of inseminations per conception. Cow fertility traits were days from calving to first breeding, days open, and number of inseminations per conception. Production traits were breed class average milk, breed class average fat, and fat percentage. Relationships among these nine traits for the first three lactations were estimated using a maximum likelihood multiple-trait procedure. The linear mixed model for each trait included fixed effects of herd-year-season of birth and genetic groups of sire and the random effect of sire. Transformations of the data for nonnormality had no influence on the estimates of genetic and phenotypic parameters. The heritability of .12 for age at first insemination, which was higher than other heifer fertility traits, indicated that selection would result in genetic response. Genetic and phenotypic correlations between heifer fertility and cow fertility and production traits in all three lactations were not different from zero. There was no genetic antagonism between fertility and subsequent production traits.

Genetic parameters for Finnish blue fox population: litter size, age at first insemination and pelt size

“…Estimate was lower for LS2 than for LS1. Heritability estimate for AFI was close to estimates by Peura et al (2004b) for blue foxes, and close to estimates by Raheja et al (1989) and Muir et al (2004) for dairy cattle. On the other hand, Hanenberg et al (2001) had higher estimates for sows (0.32).…”

“…Peura et al (2004b) estimated heritability of AFI to be between 0.16 and 0.18 for blue foxes. For pigs and dairy cattle, heritability of AFI ranges between 0.11 and 0.32 (Raheja et al 1989, Hanenberg et al 2001, Muir et al 2004. In pig production and in dairy milk production, the main selection goal is to achieve economic benefit by shorter farrowing or calving interval.…”

Genetic and environmental factors affecting some reproductive traits of Holstein cows in Cuba

“…In figure 1 it can be observed that the magnitude of the month effect is very intense for all cattle categories; however, it would be evident that this environmental stress was twice as high for heifers and first calving females as for the rest of the cows. In fact, this behavior is contradictory in the literature (Thatcher, 1974;Thatcher et According to our results it was clear that the h 2 for different fertility traits were low (< 5%) and similar to many reports on this subject (see review of Men6ndez Buxadera, 1993); however, the genetic variability (table IV) was higher than most of the results in the literature (see Janson, 1980;Berger et al, 1981;Raheja et al, 1989 for SG and Baptist and Gravert, 1973;Janson, 1980;Jansen, 1986 (1981), Hansen et al (1983), Jansen (1986) and Strandberg and Danell (1988) who obtained a small increase in h 2 and CVg in older females. For the rest of the traits it was evident that these genetic parameters were higher in the first two stages (heifer and first calving), which is in correspondence to Van Raden et al (1987), Raheja et al (1989) and Weller (1989 (Janson, 1980;Distl, 1982;Jansen, 1986) …”

Rearing strategy and optimizing first-calving targets in dairy heifers: a review

“…Moreover, fertility of both dairy heifers and cows has declined over the last 10 years (Barbat et al, 2005). For some authors they are correlated and for others they are independent (Raheja et al, 1989). Even though fertility is generally higher in heifers than in cows, rearing management can highly influence heifers' fertility.…”