Effect of rectal temperature on efficiency of artificial insemination and embryo transfer technique in dairy cattle during hot season

Abstract

This study aimed to evaluate the effects of rectal temperature (RT) as well as artificial insemination (AI) technique on pregnancy rates in Holstein cows and artificial insemination or embryo transfer (ET) techniques in Holstein heifers during summer. The experiments were conducted on five dairy farms in Hungary, where 1 631 data were examined. The RT was measured immediately before reproductive techniques using a digital thermometer. The effects of animal group and month on RT were analysed. The enhancement of RT until September can be seen in heifers, but the highest RT of cows occurred during July. In line with the enhancement of RT the pregnancy rate decreased in all groups; the lowest (cows) and the highest (heifers) value was observed in July. Moderate to high negative coefficients of correlation were detected between rectal temperature and pregnancy rate for particular groups (r = −0.3 – −0.7). More than 92% of ET, 48% and 16% of inseminated heifers and cows were pregnant up to the category of 39.1<sup> </sup>°C of RT, above this it did not change considerably in the inseminated groups. In inseminated animals with RT higher than 39.1 °C significantly higher services per conception could be observed contrary to ET heifers. ET may become a more effective strategy to improve pregnancy success in heifers compared to AI during summer.

Negative impact of heat stress on reproduction in cows: Animal husbandry and biotechnological viewpoints: A review

“…The negative effect of heat stress on the physiology of both male (bulls) and female (cows; heifers) reproduction has been described in a number of studies. The impact of the hot summer period on the reproduction of bulls is manifested mainly by a deterioration in sperm quality (Dolezalova et al 2016;Biniova et al 2018;Zubor et al 2020). Concerning female reproduction, an association between heat stress and ovarian activity, the number and quality of oocytes and transferable embryos can be probably reflected in other reproduction problems (Schuller et al 2017;Bezdicek et al 2019).…”

A Comparative Evaluation of the Alternative Anatomical Sites for Body Temperature Measurement Using Digital Thermometers in Dairy Cows

“…Rectal thermometry is the gold standard for body temperature assessment in cows (Zubor et al, 2020;Giannetto et al, 2022). However, this method is associated with potential risks, such as stress, disease spread, and rectal injuries to cattle (Yadav et al, 2017).…”

The Melatonin Treatment Improves the Ovarian Responses After Superstimulation in Thai-Holstein Crossbreeds Under Heat Stress Conditions

“…Embryo transfer has been used rather than artificial insemination to enhance pregnancy rates throughout the summer season as the transferrable blastocysts have greater heat resistance than in-vivo derived embryos ( 1 ). However, the good quality of transferrable embryos should be collected from non-heat stressed cattle ( 2 ).…”