Phenomics

Can wearable technology improve selection for fertility in New Zealand dairy cows?

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Abstract

Adoption of wearables for estrus detection on New Zealand farms is increasing rapidly. Between 2018 and 2023 the proportion of farms with wearables increased from 3% to 18%, providing the opportunity to use device-generated estrus alerts for fertility phenotypes. These phenotypes may offer higher heritability and reduced bias compared to traditional fertility traits. The objectives of this study were to estimate the genetic parameters associated with a cow's ability to return to estrus after calving using wearable technologies, and to estimate the genetic correlation of this trait with the pregnancy rate 42 days after the start of the herd's mating period (PR42, a key breeding goal or trait in New Zealand animal evaluation). The interval from calving to first estrus alert (CFHA) was defined as the number of days from calving to first estrus alert. PR42 was defined as a binary trait indicating whether a cow conceived within the first 42 days from the start of the mating period (coded as 1 for conception, 0 otherwise). Estrus alerts were available for 5 commercially available wearables in 517 commercial herds. The final phenotypic dataset included 1,445,436 PR42 records from 1,149,769 cows and 167,303 CFHA records from 143,363 cows born between 2010 and 2023. The pedigree included 4,621,116 animals, traced back 5 generations. Genetic analysis was conducted using the average information REML algorithm in the APEX - Linear Model Suite statistical package. A bivariate repeatability animal model was used to estimate variance components and heritabilities for each trait and genetic correlations between traits. The model included the fixed effects of herd-calving year-lactation contemporary group (2,730 levels for CFHA, 22,000 levels for PR42), calving week (53 levels for CFHA), estrus detection supplier (5 levels for CFHA), calving system (i.e., Spring calving and split calving for CFHA), age at calving within lactation for PR42, an individual's (pedigree-based) inbreeding coefficients, breed proportions (Jersey, Holstein, Friesian, Ayrshire), heterosis effects, genetic group covariates, and random effects for additive genetic variation, permanent environment and residual effects. Estimates of heritability were 0.024 for PR42 and 0.11 for CFHA. The genetic correlation between PR42 and CFHA was negative and strong (-0.64), indicating that cows with a shorter interval from calving to first cyclic estrus are more likely to conceive within 6 weeks of the mating start date. This favorable genetic correlation suggests that CFHA could serve as an early indicator trait for PR42, since selection for shorter CFHA is expected to indirectly improve PR42. These findings suggest that including CFHA in the genetic evaluation of female fertility could improve selection effectiveness.

Keywords: 2026

How to Cite:

Ismael, A., McNaughton, L., Friedeman, J., Xu, Z., Tiplady, K., Boerner, V., Sherlock, R., Harris, B. & Spelman, R., (2026) “Can wearable technology improve selection for fertility in New Zealand dairy cows?”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285189. doi: https://doi.org/10.31274/wcgalp.23637

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