The effect of high temperature and humidity on milk yield in Ankole and crossbred cows

Yvan Bienvenu Niyonzima,Erling Strandberg,Claire D’Andre Hirwa,Martin Ntawubizi,Maximilian Manzi,Lotta Rydhmer

doi:10.1007/s11250-022-03092-z

Abstract

Tropical regions are characterized by high temperature and humidity across the year. At high values of temperature humidity index (THI), there is a risk of heat stress leading to lower milk yield. The objective of this study was to describe the effect of season and the effect of maximum daily THI on milk yield of that day in purebred Ankole and Ankole-Friesian, Ankole-Jersey and Ankole-Sahiwal crosses in a tropical climate. In total, 53,730 records of daily milk yield from 183 cows in Rwanda were analyzed. The results showed that THI had a negative effect on daily milk yield above a threshold, but the effect was small (− 0.11 kg milk/THI unit at most). Purebred Ankole cows had the lowest daily milk yield and the lowest threshold (THI mean 66), as compared to the crossbreds (THI mean 68–69). Ankole-Friesian had a steeper decline in daily milk yield above the threshold than Ankole. The crossbreds, especially Ankole-Friesian, had higher daily milk yield than purebred Ankole also at very high THI. The results indicate some differences between breed groups in the way of coping with a hot and humid climate and raise questions about dairy cows’ adaptation to such a climate.

Highlights

Dairy cattle play an important role for food security in Rwanda (Ter Steeg 2019) and there is a clear political will to increase dairy production (Mugabo et al 2019)
Season had a significant effect on daily milk yield (DMY), and DMY was highest during LRS and lowest during SRS (Table 5)
High temperature humidity index (THI) has a negative influence on daily milk yield according to many studies (Kadzere et al 2002)

Summary

Introduction

Dairy cattle play an important role for food security in Rwanda (Ter Steeg 2019) and there is a clear political will to increase dairy production (Mugabo et al 2019). The indigenous Ankole breed is characterized by a high ability to cope with harsh environments, but the milk yield is low (Wurzinger et al 2014; Manzi et al 2020). Crossbreeding has been part of the government policy in order to increase milk and meat production, and state-subsidized artificial insemination campaigns have resulted in hundreds of thousands of crossbred cows in Rwanda (Manzi et al 2018). Rwanda Agriculture and Animal Resources Development Board, P.O. Box 5016, Rubona, Huye District, Rwanda

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