Reproductive efficiency and survival of Holstein-Friesian cows of divergent Economic Breeding Index, evaluated under seasonal calving pasture-based management

Abstract

The objective of the current study was to examine phenotypic fertility performance and survival, and to gain insight into underlying factors that may contribute to greater fertility performance in 2 divergent genetic groups (GG) of Holstein-Friesian, selected using the Irish Economic Breeding Index (EBI). The GG were evaluated across 3 spring calving pasture-based feeding treatments (FT) over 4 yr. The 2 divergent GG were (1) high EBI; representative of the top 5% nationally (elite), and (2) EBI representative of the national average (NA). In each year, 90 elite and 45 NA cows were randomly allocated to 1 of 3 FT: control, lower grass allowance, and high concentrate. No interaction between GG and FT was observed for any of the measures of fertility investigated. The elite cows achieved significantly greater pregnancy rate to first service (+14.9 percentage points), and significantly greater pregnancy rates after 21, 42, and 84 d of breeding (+17.3, +15.2, and +9.6 percentage points, respectively) compared with NA. The number of services per cow was fewer for elite (1.57) compared with NA (1.80). The interval from mating start date to pregnancy was significantly shorter for elite cows compared with NA. The elite cows maintained greater mean body condition score than NA throughout the study (2.91 vs. 2.72), and had greater body condition score at calving, artificial insemination, and drying off compared with NA. The elite cows had greater mean circulating concentrations of insulin-like growth factor-1 compared with NA. No significant effect was observed of GG on commencement of luteal activity, or progesterone profile variables. Greater survival to the start of fifth lactation was observed for elite cows. The elite cows were 43% less likely to be culled than NA by the beginning of the fifth lactation. The results highlight the success of the Economic Breeding Index to deliver reproductive performance and longevity consistent with industry targets across a range of seasonal pasture-based FT. The results also clearly demonstrate the potential of appropriate genetic selection to reverse negative fertility trends incurred during previous decades of selection for milk production alone.

An assessment of the production, reproduction, and functional traits of Holstein-Friesian, Jersey × Holstein-Friesian, and Norwegian Red × (Jersey × Holstein-Friesian) cows in pasture-based systems

“…Ireland (ICBF, 2019a;O'Sullivan et al, 2020). Coffey et al (2016) compared the reproductive performance of Holstein, Friesian, and Jersey crossbred cows in springcalving commercial dairy farms in Ireland and found an average submission rate of 74% and a 6-wk pregnancy rate of 66% from 2008 to 2012 with no consistent genotype effect noted, although calving interval and age at first calving were significantly lower for crossbred animals compared with both parental averages.…”

Cross-sectional analyses of a national database to determine if superior genetic merit translates to superior dairy cow performance

“…Cows excelling in either EBI, fertility subindex, or EBV for calving interval or survival outperformed their genetically inferior contemporaries for reproductive performance; such findings are supported by Cummins et al (2012) andO'Sullivan et al (2020), which were based on Irish controlled experimental results. That said, the overestimation of the expected effect of calving interval EBV on phenotypic performance in the present study warranted further investigation.…”

“…Based on analyses of 2,185 dairy cows from 5 US herds, Fessenden et al (2020) observed favorable phenotypic differences in milk, fat, and protein yield, live calves, time spent in the lactating herd, and cow mortality between cows that diverged on their genetic merit for the Dairy Wellness Profit Index. These studies (Newton et al, 2017;O'Sullivan et al, 2019O'Sullivan et al, , 2020Fessenden et al, 2020) represent much of the published research on validation of EBV comprising national dairy breeding goals, which typically consider few animals, are generally limited in both genetic lineages and farming practices, and are generally limited to the study of a few traits. Due to the paucity of such studies internationally (Pryce et al, 2018), it is necessary to validate the constituent EBV of the Irish total merit index under a commercial setting with a large relevant data set.…”

“…Due to the paucity of such studies internationally (Pryce et al, 2018), it is necessary to validate the constituent EBV of the Irish total merit index under a commercial setting with a large relevant data set. Such analyses are required to demonstrate the robustness of traits included in national breeding goals, but also the breeding goal itself, and to substantiate whether or not results from such experimental studies (Newton et al, 2017;O'Sullivan et al, 2019O'Sullivan et al, , 2020Fessenden et al, 2020) can be extrapolated to the national population.…”

The effect of nutritional management in early lactation and dairy cow genotype on milk production, metabolic status, and uterine recovery in a pasture-based system

“…The EBI is relatively new, having been established in 2001 (Veerkamp et al, 2002;, but it is changing rapidly due to advances in technology and genomic selection. Recent research has validated the current EBI in terms of milk production (O'Sullivan et al, 2019b) and fertility performance (O'Sullivan et al, 2020) under varying levels of feeding management. However, none of this research evaluated TMR for the first 30 d as a strategy.…”