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A study on stress response and fertility parameters in phenotypically thermotolerant and thermosensitive dairy cows during summer heat stress
- Source :
- Reproduction in Domestic Animals. 55:1774-1783
- Publication Year :
- 2020
- Publisher :
- Wiley, 2020.
-
Abstract
- It is well documented that heat stress (HS) causes subfertility in dairy cows. However, during the last ten years we have been observing that, under high temperature-humidity index (THI ≥ 75), despite the overall reduced fertility, some cows conceive at the first artificial insemination (AI). Here, we examined distinctive features of cows with conserved fertility under severe HS. From the databases of three herds, 167 lactating Holstein cows were selected; group TT cows (n = 57) conceived in the previous summer (THI ≥ 75) at the 1st AI, and group TS (n = 110) failed to conceive at the same period after at least 2 consecutive AIs. The animals calved in spring, and in August, blood samples were collected during a hot day (THI ≥ 81) for the determination of cortisol and HSP70 concentrations. In one farm, the validity of fertility data of the previous year was re-examined. In 28 cows from group TT and in 39 cows from group TS, the conception rate was examined during July and August. In 6 cows from each group (TT and TS) the oestrous cycles were synchronized, ovulation was induced with GnRH (THI = 80), and the concentration of the pre-ovulatory LH surge was determined in 9 blood samples. The progesterone concentration in the ensuing cycle was determined in blood samples collected every other day. Overall, cortisol and HSP70 were significantly lower in TT group compared to TS. More (p < .05) animals from group TT conceived at the first AI compared with those from group TS. The induced pre-ovulatory LH surge peaked at higher level (p < .002) in group TT than in group TS, while no difference was recorded among groups either in mean progesterone concentrations or in the duration of the ensuing oestrous cycle. These results are highly suggestive that thermotolerance in some dairy cows is an inherent characteristic, warranting further genetic investigation.
- Subjects :
- Thermotolerance
Hydrocortisone
Summer heat
media_common.quotation_subject
medicine.medical_treatment
Fertility
Biology
Fight-or-flight response
03 medical and health sciences
0302 clinical medicine
Endocrinology
Animal science
Pregnancy
medicine
Animals
HSP70 Heat-Shock Proteins
Ovulation
Insemination, Artificial
media_common
Estrous cycle
030219 obstetrics & reproductive medicine
Greece
Artificial insemination
0402 animal and dairy science
04 agricultural and veterinary sciences
Luteinizing Hormone
040201 dairy & animal science
Dairying
Reduced fertility
Herd
Cattle
Female
Animal Science and Zoology
Seasons
Heat-Shock Response
Biotechnology
Subjects
Details
- ISSN :
- 14390531 and 09366768
- Volume :
- 55
- Database :
- OpenAIRE
- Journal :
- Reproduction in Domestic Animals
- Accession number :
- edsair.doi.dedup.....8607bc7d8b1bbce0ecd0086f3500d6fd