Postpartum oestrous cycling resumption of yak cows following different calf weaning strategies under range conditions

Abstract

Early weaning can improve body condition and reproductive performance of cows. The objectives of this study were to examine and compare oestrous cycling resumption, behaviour and blood parameters of yak cows following four different strategies of calf weaning. Twenty-six yak cows (4-8 years) and their calves (94.3 ± 2.4 days) were studied in which calves were: weaned naturally with free access to their mothers (NW; n = 13); weaned abruptly and separated permanently from their mothers (PW; n = 5); separated temporarily from their mothers for 15 days (TW; n = 5); and fitted with nose plates for 15 days, but allowed free access to their mothers (NP; n = 3). Yak cows with sucking calves (NW) spent more time grazing in the cold season (from d 39 to 84). Based on serum progesterone concentrations, none of nine NW yak cows resumed oestrous cycling during the study, while seven of nine yak cows with weaned calves resumed cycling (3/3 for PW; 2/3 for TW; and 2/3 for NP yaks). We concluded that early weaning improved postpartum reproductive performance of yak cows on the Qinghai-Tibetan plateau and that abrupt and permanent weaning was an appropriate strategy.

Body status and blood metabolites profiles during resumption of postpartum ovarian activity in yak (Poephagus grunniens)

“…Hence, a few yaks use to return to oestrus after calving in the first breeding season, and mostly in the second or third year. But, when yak calves are weaned from their dams, around 77.7% yak cows resumed their cycling activities; however, no cyclic activity was seen in suckled dams (Liu et al, 2018).…”

“…Hence, a few yaks use to return to oestrus after calving in the first breeding season, and mostly in the second or third year. But, when yak calves are weaned from their dams, around 77.7% yak cows resumed their cycling activities; however, no cyclic activity was seen in suckled dams (Liu et al., 2018). Therefore, like other beef and dairy cows (reviewed by Crowe, 2008; Crowe et al., 2014), adequate nutrition and body reserve status may also be the major regulators of postpartum ovarian function in yak.…”

A comparative transcriptome and proteomics study of post‐partum ovarian cycle arrest in yaks (Bos grunniens)

“…Post‐partum ovarian cycle arrest is also such an adaptive strategy occurring post‐partum, which assists yaks to survive unfavourable environments. Post‐partum ovarian cycle arrest is regulated through nutrition, hormones and genetic factors (Huo et al., 2018; Liu et al., 2018; Qiu et al., 2012). Yak reproductive characteristics include late reproductive onset after five years of age, seasonal oestrus starting every July and a long generation interval resulting in one foetus in two years or two foetuses in three years (Huo & Long, 2014; Sarkar et al., 2006; Sarkar & Prakash, 2005; Yu & Chen, 2000).…”

“…

The adverse environment of high altitude and extreme cold on the Tibetan Plateau is a challenge to the survival of yaks, and they have evolved multiple strategies to adapt to environmental conditions.Post-partum ovarian cycle arrest is also such an adaptive strategy occurring post-partum, which assists yaks to survive unfavourable environments. Post-partum ovarian cycle arrest is regulated through nutrition, hormones and genetic factors (Huo et al, 2018;Liu et al, 2018;Qiu et al, 2012). Yak reproductive characteristics include late reproductive onset after five years of age, seasonal oestrus starting every July and a long generation interval resulting in one foetus in two years or two foetuses in three years (Huo

…”

A Comparative Transcriptome and Proteomics Study of Postpartum Ovarian Cycle Arrest in Yaks

“…Postpartum ovarian cycle arrest is an adaptive strategy occurring postpartum, which assists yaks to survive unfavorable environments. Postpartum ovarian cycle arrest is regulated through nutrition, hormones and genetic factors [1][2][3]. However, due to the severe living conditions, yak reproductive characteristics include late reproductive onset after ve years of age, seasonal estrus starting every July and a long generation interval resulting in one fetus in two years or two fetuses in three years [4][5][6][7].…”