EFFECTS OF HEAT STRESS ON SEXUAL BEHAVIOR IN HEIFERS
High ambient temperatures affect the secretion of sexual hormones in cows and heifers. As a result, the frequency of silent estrus can reach a high level during summer. In order to analyze the effects of heat stress on sexual behavior in Black and White Romanian heifers, a research has been conducte...
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| Format: | Article |
| Language: | English |
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Agroprint Timisoara
2023-10-01
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| Series: | Scientific Papers Animal Science and Biotechnologies |
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| Online Access: | https://spasb.ro/index.php/public_html/article/view/1201 |
| Summary: | High ambient temperatures affect the secretion of sexual hormones in cows and
heifers. As a result, the frequency of silent estrus can reach a high level during
summer. In order to analyze the effects of heat stress on sexual behavior in Black
and White Romanian heifers, a research has been conducted on four groups of
animals in the pre- and post-AI interval. During spring, in conditions of thermal
comfort and under the stimulating influence of increasing photoperiod, 83.3% of the
heifers showed clear signs of estrus. Exposure to temperatures of 36-42○C by day
and 21-31○C by night caused anoestrus: the heifers did not respond to repeated
estrus-induction treatment. When hot days (33-38○C) alternated with tolerable
temperatures by night (18-21○C), a normal expression of estrus was noticed in
16.7% of the animals, while 33.3% experienced weak estrus and 50% did not exhibit
sexual behavior. In conditions of moderate thermal stress, with peaks of daily
temperature ranging from 28 to 34○C, clear signs of estrus were detected in 25% of
the heifers and weak symptoms in 41.7%, while 33.3% had silent heat, clinically
diagnosed. The circadian profile of behavior changes in heat-stressed heifers, whose
sexual activity shifts to night time and to the early hours of the morning. |
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| ISSN: | 1841-9364 2344-4576 |