Effects of hormonal interventions on fertility outcomes in dairy cattle exposed to heat stress: a meta-analysis
6 affiliations
- 1Department of Animal Science, Faculty of Agriculture, Lilongwe University of Agriculture and Natural Resources
- 2Department of Veterinary Biomedical Sciences, Faculty of Veterinary Medicine, Lilongwe University of Agriculture and Natural Resources
- 3Department of Human Ecology, Faculty of Food and Human Sciences, Lilongwe University of Agriculture and Natural Resources
- 4Department of Biomedical Sciences, School of Veterinary Medicine, The University of Zambia
- 5FoodPlus Research Group, Faculty of Life Sciences and Natural Resources, LUANAR (NRC Campus)
- 6Laboratory of Animal Reproduction, Department of Animal Science, School of Veterinary Medicine, Kitasato University
Abstract
Normalization of the deranged hormonal milieu using hormonal therapy has been recommended as a strategy to improve the fertility of heat-stressed dairy cows, yet evidence of its effectiveness remains elusive and inconsistent. We conducted a meta-analysis to assess the effect of hormonal interventions in improving fertility in dairy cows exposed to heat stress. Ninety-eight trials reported across 32 studies were included in the meta-analysis. GnRH and progesterone, but not hCG, increased the chances of conception when administered around or post-insemination (RR = 1.26, P = 0.0001; I2 = 37%, RR 1.98, P < 0.00001; I2 = 35%, and RR = 1.06, P = 0.65; I2 = 4%, respectively). The risk of pregnancy loss was significantly reduced following post-estrus or AI treatment with GnRH or hCG (RR 0.47, P = 0.004; I2 = 53%), although with limited evidence. No evidence of the benefits of timed artificial insemination on conception rates in heat-stressed dairy cattle was found (RR = 1.04, P = 0.73). Subgroup analysis showed that conception rates following GnRH, hCG, and progesterone treatments varied with factors such as body condition score and presence of reproductive diseases at the time of treatment. Heterogeneity was generally low or moderate across the main analyses. We conclude that hormonal treatment may improve the fertility of dairy cattle in a manner that varies with the nature of the treatment and the physiological status of the animals at the time of application.
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BibTeX
@article{kothowa2026effects,
title = {{Effects of hormonal interventions on fertility outcomes in dairy cattle exposed to heat stress: a meta-analysis}},
author = {John Kothowa and Laureen Mbewe and Verson Nambuzi and Hosea Katete and Elizabeth Alinafe Mzumara and Merning Mwenifumbo and Muloongo C. Sitali and Liveness Banda and Limbikani Matumba and Masashi Nagano and Madalitso Chelenga},
journal = {Scientific Reports},
year = {2026},
month = sep,
doi = {10.1038/s41598-026-71643-7},
url = {https://doi.org/10.1038/s41598-026-71643-7},
note = {CC BY},
}
RIS
TY - JOUR
TI - Effects of hormonal interventions on fertility outcomes in dairy cattle exposed to heat stress: a meta-analysis
AU - John Kothowa
AU - Laureen Mbewe
AU - Verson Nambuzi
AU - Hosea Katete
AU - Elizabeth Alinafe Mzumara
AU - Merning Mwenifumbo
AU - Muloongo C. Sitali
AU - Liveness Banda
AU - Limbikani Matumba
AU - Masashi Nagano
AU - Madalitso Chelenga
PY - 2026
DA - 2026/09/01
JO - Scientific Reports
DO - 10.1038/s41598-026-71643-7
UR - https://doi.org/10.1038/s41598-026-71643-7
AB - Normalization of the deranged hormonal milieu using hormonal therapy has been recommended as a strategy to improve the fertility of heat-stressed dairy cows, yet evidence of its effectiveness remains elusive and inconsistent. We conducted a meta-analysis to assess the effect of hormonal interventions in improving fertility in dairy cows exposed to heat stress. Ninety-eight trials reported across 32 studies were included in the meta-analysis. GnRH and progesterone, but not hCG, increased the chances of conception when administered around or post-insemination (RR = 1.26, P = 0.0001; I2 = 37%, RR 1.98, P < 0.00001; I2 = 35%, and RR = 1.06, P = 0.65; I2 = 4%, respectively). The risk of pregnancy loss was significantly reduced following post-estrus or AI treatment with GnRH or hCG (RR 0.47, P = 0.004; I2 = 53%), although with limited evidence. No evidence of the benefits of timed artificial insemination on conception rates in heat-stressed dairy cattle was found (RR = 1.04, P = 0.73). Subgroup analysis showed that conception rates following GnRH, hCG, and progesterone treatments varied with factors such as body condition score and presence of reproductive diseases at the time of treatment. Heterogeneity was generally low or moderate across the main analyses. We conclude that hormonal treatment may improve the fertility of dairy cattle in a manner that varies with the nature of the treatment and the physiological status of the animals at the time of application.
SN - 2045-2322
ER -