Relationships Between Reproduction Traits, Age and Body Weight at Calving, and Days Dry in First Lactation Ayrshires and Holsteins

Abstract

Individual cow test day records collected between December 1979 and June 1986 were used to calculate measures of reproductive performance, age and weight at calving, and days dry for 7824 Ayrshire and 79,755 Holstein cows in first lactation. Separate analyses by breed were carried out according to a multiple-trait mixed model. Sixty-two Ayrshire and 369 Holstein sires were treated as random in the analyses. Ayrshires were, on average, older and lighter at calving than Holsteins, but the breeds differed little in reproduction measures and days dry. Heritabilities of fertility traits, days to first breeding, days open, and services per conception were all less than .015 in the multi-trait analyses. With the exception of body weight, heritability estimates for the other traits were less than .05. Phenotypic correlations between traits were almost identical for the two breeds, and genetic correlations tended to be similar. Exceptions involved the trait days to first breeding and services per conception, but heritabilities of these traits were close to zero (p less than .008) in Ayrshires. Fertility traits were positively correlated genetically. Genetic correlations between days open and both age and body weight at calving were small. The genetic correlation between age and weight at calving was -.90 and -.68 in Ayrshires and Holsteins, respectively. Genetic correlations between days dry and all traits except body weight were moderate and positive.

Estimation of Genetic and Non-Genetic Parameters of Friesian Cattle under Hot Climate

“…AFC was negatively correlated with GP and positively with S/C, this findings is similar to the results of Moore et al (1990) and Abubakar et al (1986) who reported a negative phenotypic correlation between AFC and GP and between AFC and TMY. Whereas Barrada et al (1969) and El Barbary et al (1983) reported positive phenotypic correlation between AFC and TMY.…”

“…Table 3. This estimate fairly agreed with Moore et al (1990) whereas El-Amin et al (1986) reported a lower estimate for the same trait. h 2 calculated by daughter-dam regression is higher than that obtained by El Amin (1969).…”

“…High estimates for the same trait were reported by Khattab and Sultan (1993) and El-Amin et al (1986) for Friesian and Friesian crossbred in Sudan, respectively. While Moore et al (1990) reported lower estimate of h 2 of AFC estimated by daughter-dam regression. h 2 of GP estimated by paternal half-sib method was found to be 0.141±0.123.…”

Fatores de variação e parâmetros genéticos dos períodos de serviço e seco em bovinos da raça Holandês no estado de Minas Gerais

“…A exemplo disto, podem ser citadas as relatadas por MOORE et al (1990), os quais obtiveram estimativas de 0,44 e 0,48 para as raças Ayrshire e Holandesa, respectivamente, enquanto MAKUZA e McDANIEL (1996), considerando também o efeito permanente de vaca, encontraram correlações de -0,15 e -0,54 na segunda e terceira lactações, respectivamente.…”

Effect of Different Feed Combinations on the Growth Performance of Cross-Bred Heifer Calves

“…Other than essential nutrients, there are performances modifiers that can accelerate the growth rate of claves and help attain early puberty in heifers. Age at puberty and calving is related with weight (Moore et al, 1990). Nutrition plays a major role in attaining the proper weight at proper time (Chaudhry et al, 1988;Marston et al, 1995).…”