Effects of body condition score at parturition and postpartum protein supplementation on estrous behavior and size of the dominant follicle in beef cows1,2

Abstract

The objective of this study was to determine the effects of BCS at calving and the amount of postpartum protein supplementation on the dominant follicle (DF) and behavioral characteristics at the first postpartum estrus of mature beef cows. Multiparous Angus x Hereford cows (n = 45) were fed to calve in thin (T; < 5) or moderate (M; >or=5) BCS. Cows were stratified by BCS and calving date, and randomly assigned to receive lesser (L; 1.2 kg/d) or greater (G; 2.5 kg/d) amounts of a 42% CP supplement. All cows grazed the same native grass pasture and were fed in individual stalls for 49 +/- 2 d. Beginning 20 d after calving, blood samples were collected from each cow thrice weekly, and estrous behavior was monitored continuously with a radiotelemetry system. At 4 to 16 h after the onset of estrus, size of the DF was determined by ultrasonography. Body condition score of T cows was less (P < 0.01) at calving than M cows; L and G cows had similar BCS at calving and at the end of the feeding period. Body weight gains during treatment did not differ for L or G cows. Duration from calving to first estrus was greater (P < 0.01) for T than M cows. The incidence of a short luteal phase before first estrus was not influenced by BCS or protein supplement. Concentrations of IGF-I in plasma tended (P < 0.07) to be greater and size of the DF was greater (P < 0.01) for M than T cows. Size of the DF tended (P < 0.06) to be greater for G than L cows. Duration and number of mounts received at the first estrus were not influenced by BCS or supplement. Pregnancy rate of M cows during the breeding season was greater (P < 0.05) than T cows. Postpartum protein intake and BCS at calving influenced the size of the DF at the first postpartum estrus in mature suckled beef cows. Cows should be managed to calve in moderate BCS and maintain BW after parturition to decrease the interval to first estrus, increase follicular development, and maximize pregnancy rate.

Effect of Changes in Body Weight, Body Condition and Back Fat During Last Month of Pregnancy on the Reproductive Efficiency of Bos indicus Cows in the Tropics of Costa Rica

“…More studies are required to critically evaluate the role of these parameters prepartum. Recently, Lents et al [6] as expected, found that pregnancy rate of cows with moderate condition during the breeding season is greater than cows with thin condition at calving. How this observation relates to events late in pregnancy remains to be tested.…”

“…Previous work to establish optimum body weight or condition score at calving for a prompt resumption of ovarian activity has rendered conflicting results. Lents et al [6] suggested that cows should be managed to calve during moderate BCS and to maintain body weight (BW) after parturition to decrease the interval to first estrus. However, prior work [7] had indicated that when beef cows are in thin to moderate body condition at calving, postpartum BW change and BCS at calving do not influence the duration of luteal activity.…”

Effects of prepartum plane of nutrition during mid- or late gestation on beef cow body weight, body condition score, blood hormone concentrations and preimplantation embryo

“…Previous literature supports that cows in moderate BCS (5-6) have increased conception rates (Lents et al 2008;Bohnert et al 2013) and decreased postpartum interval (Lents et al 2008) when compared with cows that are in poor BCS (4). In Exp.…”

“…Embryo transfer became a viable option for the North American beef industry during the early 1970s (Hasler 2003). Considerable evidence exists which implicates that prepartum nutritional management will improve subsequent reproductive performance in beef cattle (Sasser et al 1988;Selk et al 1988;Lents et al 2008). Prepartum nutrition affects BW and BCS (Stalker et al 2006;Bohnert et al 2013) and can alter circulating hormone concentrations (Wiley et al 1991;Lalman et al 1997) that are important in cattle achieving reproductive success.…”

Holştayn ırkı ineklerde vücut kondisyon skorunun fertilite ve bazı reprodüktif parametrelere etkisi

“…Vücut kondisyon skoru ile preovulatör follikül çapı arasında bir ilişki gözlenme-miştir. Ancak yapılan bazı çalışmalarda preovulatör follikül çapının, sunulan çalışmada kullanılan ineklerde olduğu gibi spontane değilde, follikül gelişimi ve ovulasyonun eksternal hormonlarla indüklenmesi durumunda önemli etkiye sahip olduğu yönündedir (5,15).…”