Does β-hydroxybutyrate concentration influence conception date in young postpartum range beef cows?1

Abstract

Cows in negative energy balance after calving often have reduced reproductive performance, which is mediated by metabolic signals. The objective of these studies was to determine the association of serum metabolites, days to first postpartum ovulation, milk production, cow BW change, BCS, and calf performance with conception date in spring-calving 2- and 3-yr-old beef cows grazing native range. In Exp. 1, cows were classified by conception date in a 60-d breeding season as early (EARLY; conceived in first 15 d of breeding) or late conception (LATE; conceived during the last 45 d of breeding). Beginning on d 35 postpartum, blood samples were collected twice per week for serum metabolite analysis and progesterone analysis to estimate days to resumption of estrous cycles. As a chute-side measure of nutrient status and glucose sufficiency, whole-blood β-hydroxybutyrate (BHB) concentrations were measured 14 ± 2 d before breeding. In Exp. 2, cows were classified by subsequent calving date resulting from a 55 ± 2 d breeding season as conceiving either early (EARLY; conceived in first 15 d of breeding) or late (LATE; conceived during the remaining breeding season). Blood samples were collected in 2 periods, 30 ± 4 d before calving and 14 ± 3 d before the initiation of breeding, to determine circulating concentrations of IGF-I and BHB. In Exp. 1, BHB and serum glucose concentrations were less (P ≤ 0.04) in EARLY cows than LATE cows. Serum insulin concentrations were greater (P = 0.03) in EARLY cows relative to LATE cows. Milk production and composition did not differ (P ≥ 0.24) by conception date groups. In Exp. 2, cow age × sample period × conception date interaction (P < 0.01) occurred for serum BHB concentrations. Serum BHB concentrations were similar (P > 0.10) for 2-yr-old cows (in greater nutritional plane compared with Exp. 1) regardless of their conception date classification and sampling period. However, precalving serum BHB concentrations were greater (P < 0.01) for LATE than EARLY in 3-yr-old cows with no difference (P = 0.86) at prebreeding. Serum IGF-1 concentrations were greater (P < 0.01) for EARLY cows relative to LATE cows at precalving and prebreeding. This study indicates that blood BHB concentrations during times of metabolic dysfunctions may provide a more sensitive indicator of energy status than body condition, predicting rebreeding competence in young beef cows as measured by interval from calving to conception.

Evaluation of grazing beef cows receiving supplements with different protein contents

“…However, serum concentrations of NEFA did not differ between treatments (Table 7). Similar results were reported by Mulliniks et al (2013), in their work with beef cows grazing on native ranges during post-calving.…”

Performance, metabolic and hormonal responses of grazing Nellore cows to an energy-protein supplementation during the pre-partum phase

“…Nevertheless, βHB levels had not influence days from calving to conception, unlike Mulliniks et al [2] who found that low βHB concentrations were associated with an earlier conception date in beef cows. The contrasting experimental results may be explained by the fact that the βHB values that impaired reproduction cited by the above authors were higher at − 30-d (0.71 mmol/L) than those of our experiment (0.48 mmol/L).…”

“…Data in the literature reveal that restricting pregnant cows' intake during the late gestation period results in weight loss, BCS loss and high serum concentrations of NEFA and βHB, which lead to long periods of negative energy balance in both dairy [27,28] and beef cows [2].…”

“…The nutritional status upon calving is the main factor influencing the duration between calving and the next conception [1,2]. It affects reproductive performance and, consequently, the economic success of any beef cattle operation.…”

Plasma estrone sulfate, clinical biochemistry, and milk yield of dairy cows carrying a fetus from a bull or its clone

“…Particular attention must be reserved to the meaning of an increased plasma BHB in the antepartum period. Ospina et al [12], and more recently Mulliniks et al [23], reported how antepartum plasma BHB may represent a signal of increased risk of pathologies at the beginning of lactation, both for dairy and beef cattle. In our case, the low yield of BWT-C cows in the first month of lactation was not associated to increased pathologies, as confirmed by a "normal" metabolic profile ( Table 5).…”