Metabolic profile of serum and follicular fluid from postpartum dairy cows during summer and winter

Abstract

This study was designed to monitor the biochemical profiles of serum and follicular fluid (FF) of postpartum dairy cows during the summer (n=30) and winter (n=30). Blood and FF (follicles ≥ 9 mm) were obtained from Girolando cows at 30, 45, 60, 75 and 90 days postpartum. The samples were collected and analysed to determine glucose, total cholesterol (TC), triglyceride (TG), urea, sodium (Na), potassium (K) and calcium (Ca) levels. Throughout the study, the following clinical variables were measured: rectal temperature (RT), respiratory rate (RR) and body condition score (BCS). In addition, the temperature humidity index (THI) was calculated for each season. During the summer season, THI was higher, BCS decreased, there was an increase in RT, and glucose, urea, Na and K serum levels were decreased (P<0.05). The levels of TC, TG, urea, K and Ca in follicular fluid increased (P<0.05). Positive correlations (P<0.05) were observed between the serum and FF levels for glucose (r=0.29), TC (r=0.24) and Ca (r=0.30). Therefore, the biochemical profile of serum and FF of dairy cows under summer heat-stress conditions demonstrates marked changes that may impair fertility during lactation.

Invited review: Management strategies capable of improving the reproductive performance of heat-stressed dairy cattle

“…In addition to the previously mentioned changes in metabolites and proteins observed during heat stress, adipose responsiveness to adrenergic stimulus is blunted (Wheelock et al, 2010), indicating that cows experiencing a thermal load reprioritize fuel selection in favor of glucose. As a result, heat-stressed cows have lower circulating glucose concentrations (Rhoads et al, 2009;Wheelock et al, 2010;Alves et al, 2014) coupled with higher concentrations of insulin (Wheelock et al, 2010). Interestingly, the results of glucose and insulin tolerance tests indicate that heat-stressed cows remain insulin-responsive, in contrast to underfed dairy cows, which typically become insulin-insensitive (Wheelock et al, 2010).…”

“…This agrees with work reported by Wilson et al (1998), who found that the second-wave dominant follicle was initially larger in heat-stressed dairy cattle, but that those follicles then grew more slowly over time, so that final diameter was detrimentally affected. The composition of the follicle fluid also differs during periods of heat stress (Alves et al, 2014), and many have reported differences in ovarian steroid concentrations between thermoneutral and heat-stressed animals (reviewed in Roth and Wolfenson, 2016).…”

Time-lagged and acute impact of heat stress on production and fertility traits in the local dual-purpose cattle breed “Rotes Höhenvieh” under pasture-based conditions

“…A reduced estradiol secretion contributed to a poor expression of estrus and ovulatory failure ( De Rensis and Scaramuzzi, 2003 ), and to the prevention of luteolysis of the corpus luteum ( Lucy, 2002 ). Furthermore, heat compromised size ( Schüller et al 2017 ), growth ( Wilson et al, 1998 ), and composition of the fluid ( Alves et al, 2014 ) of the ovarian follicle. Due to carryover effects from summer, HS-induced oocyte damage also impairs fertility in autumn.…”

Effects of mineral supplementation on reproductive performance of pregnant cross‐breed Bonsmara cows: An experimental study

“…The present study showed the mean TRIG (2.0167 ± 0.384 mM) level was above normal in the control group (Table ). Other researchers have associated negative energy feedback and high nutritional requirements with low levels of triglycerides (Alves et al, ; Petkova, Kitanov, & Girginov, ). In situations of positive energy balance, triglycerides are likely to be high (Sevinç, Başoğlu, Güzelbektaş, & Boydak, ).…”