Changes in the genetic level and the effects of age at first calving and milk production on survival during the first lactation over the last 25 years

Abstract

Survival during the first year after first calving was investigated over the last 25 years, 1989-2013, as well as how the association of survival with season of calving, age at first calving (AFC) and within-herd production level has changed over that period. The data set contained 1 108 745 Dutch black-and-white cows in 2185 herds. Linear models were used to estimate (1) effect of year and season and their interaction and (2) effect of AFC, within-herd production level, and 5-year intervals and their two-way interactions, and the genetic trend. All models contained AFC and percentage of Holstein Friesian as a fixed effect, and herd-yearseason, sire and maternal grandsire as random effects. Survival and functional survival were analysed. Functional survival was defined as survival adjusted for within-herd production level. Survival rate increased by 8% up to 92% in the last 25 years. When accounting for pedigree, survival showed no improvement up to 1999, but improved since then. Genetically, survival increased 3% to 4% but functional survival did not increase over the 25 years. We found an interesting difference between the genetic trends for survival and functional survival for bulls born between 1985 and 1999, where the trend for survival was still increasing, but was negative for functional survival. Since 1999, genetic trend picked up again for both survival and functional survival. AFC, season of calving and within-herd production level affected survival. Survival rate decreased 0.6%/month for survival and 1.5% for functional survival between AFC of 24 and 32 months. Calving in summer resulted in 2.0% higher survival than calving in winter. Within herd, low-producing cows had a lower survival rate than high-producing cows. However, these effects became less important during the recent years. Based on survival optimum AFC is around 24 months, but based on functional survival it is better to have an AFC < 24 months. Overall, survival rate of heifers has improved considerably in the past 25 years, initially due to the focus on a high milk production. More recently, the importance of a high milk production has been reduced towards attention for functional survival.Keywords: dairy cattle, longevity, survival, age at first calving, within-herd production level ImplicationsSurvival rate in the first year after calving increased from 8% to 92% between 1989 and 2013. Genetic selection made a positive contribution of 4% for survival, whereas functional survival -adjusted for within-herd production level -declined until 1999 and is since then increasing again. Culling risk increased with older age at first calving (AFC) and decreased with higher production within herd. However, over the years, the effect of AFC and production level on survival in first lactation has reduced significantly. IntroductionThe dairy industry has undergone profound changes in recent decades, that potentially affect the productivity, health and welfare of dairy cows, for example, herd size, use of hired labour, housing system, milk price and...

Principal component and cluster analyses of production and fertility traits in Red Sindhi dairy cattle breed in Brazil

“…According to literature review, age at first calving (AFC) is very important for milk production systems, whereas, as the smaller, as soon the cow become more productive, allowing a greater number of offspring's during its reproductive life and greater intensity of breeding, which will reflect in higher milk yield. Conversely, when high in general, this reflects the lack of adaptation of animals to their environment (Silva et al 1998;Pelicioni et al 1999;Wenceslau et al 2000;Ettema and Santos 2004;Facó et al 2005;Coelho et al 2009;Vieira et al 2010;Krpálková et al 2014;Van Pelt et al 2016;Heise et al 2018). In our study, the traits total milk yield (TMY) and age at first calving (AFC) contributed the most to cluster of the Red Sindhi dairy cows.…”

Predicting survival in dairy cattle by combining genomic breeding values and phenotypic information

“…Age at first calving, which is also an indication of fertility, was always selected when available. A higher age at first calving was associated with higher costs, lower fertility, and higher risk of culling overall (Sewalem et al, 2008;van Pelt et al, 2016a). Interestingly, despite the availability of 2 parities worth of phenotypic fertility records, fertility gEBV were still selected by the combined model in the fifth decision moment.…”

A large-scale study on the effect of age at first calving, dam parity, and birth and calving month on first-lactation milk yield in Holstein Friesian dairy cattle

“…As a consequence, researchers have repeatedly studied and identified factors associated with the amount of milk produced during first lactation. In our previous study, assessing the effect of several pre-and postnatal factors on first-lactation performance, age at first calving (AFC) was shown to be strongly associated with first-lactation milk yield (Van Eetvelde et al, 2017). As decreasing the AFC reduces rearing costs, the aim is to have heifers calving for the first time no later than 24 mo (Ettema and Santos, 2004).…”