“Female cattle in oestrus may mount any adult cattle, especially a bull (fertile male) if one is present, but they will also mount castrated males or other females. … Bulling is used by farmers to recognise oestrus, which is important to determine the fertile period when cows may be artificially inseminated.”
https://en.m.wikipedia.org/wiki/Bulling_(cattle) Image by Davidoff
“Check Mate”
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Courtesy Dr Sim Sischy
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