Estimation & Prediction

Effects of Various Factors on Reproductive Efficiency in Dairy Cattle

---

Abstract

Reproductive traits like inter-calving period (ICP), age at first calving (AFC), and gestation length in dairy cattle are crucial for both production, breeding and overall economics on a farm. In this regard, we examined various reproductive traits in a dairy cattle population using advanced statistical modelling approaches. We analyzed the reproduction related data of female dairy cattle maintained on a dairy farm, representing multiple breed groups. Multiple imputations using iterative imputation were employed to recover observations with partial missing data. Statistical analyses employed mixed-effects linear models (MixedLM), generalized estimating equations (GEE), cluster-robust ordinary least squares (OLS), robust regression, quantile regression, and Random Forest regression. Each additional parity shortened inter-calving period (ICP) by 8.9 days (95% CI: -13.8 to -4.1, p=0.0003, GEE) and lengthened gestation by 0.65 days (95% CI: 0.27 to 1.03, p=0.0008, GEE). Quantile regression revealed the strongest parity effects at the 25th quantile (-10.4 days, p< 0.001) for efficient cows. Random Forest identified age at first calving (AFC) as most important (43.8%), followed by gestation (26.9%), birth weight (18.5%), and parity (10.8%). Breed effects were significant for AFC (p=0.024) but not for ICP or gestation. These findings demonstrate that higher-parity cows return to calving faster, with effects strongest for efficient cows. Early-life factors are substantially more predictive than parity, supporting the importance of heifer development programs. These findings bear direct consequences for selective reproductive management based on parity stage in small dairy herds.

Keywords: 2026

How to Cite:

Hamadani, A., Hamadani, H., Ganai, N., Khan, H. & Ali, R., (2026) “Effects of Various Factors on Reproductive Efficiency in Dairy Cattle”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286310. doi: https://doi.org/10.31274/wcgalp.23918

Rights: 1