In the second article in this series on the impact of climate change on South Africa's dairy herd (see, 9 December 2022), I discussed the negative effects of heat stress on milk production.
In this article, I focus on the impact that increased temperatures and humidity have on the conception rate of a dairy herd.
As mentioned before, South Africa's average maximum temperature (MT) rose by 0,9°C between from 1933 to 2020. Between 1960 and 2020, the average conception rate in dairy cows dropped by 4.9%, which has obviously had a negative effect on local milk production and farmers' profit margins.
LONG-TERM CONCEPTION RATES
In order to calculate the, where THI represents the temperature-humidity index.