Effect of body condition and suckling restriction with and without presence of the calf on cow and calf performance

Abstract

Nutrition and suckling are largely recognised as the most important factors affecting the postpartum period and consequently the reproductive efficiency of beef cattle. The aim of this study was to evaluate the effects of body condition score (BCS) and suckling restriction with and without the presence of the calf on milk production, reproductive efficiency and calf performance. Sixty-three crossbred (Angus · Hereford) multiparous cows were managed to maintain different BCS at calving and thereafter (low vs moderate; L, n = 31 and M, n = 32). Within each group of BCS (L and M) at week 9 postpartum (66 AE 0.88 days postpartum) cows were assigned to three suckling treatments (ST): (i) suckling ad libitum (S, n = 20); (ii) calves fitted with nose plates during 14 days remaining with their dams (NP, n = 22); and (iii) calves were completely removed from their dams for 14 days, and thereafter returned (CR, n = 21). Milk production was assessed by milking procedure at Day 65 (the day before onset of ST) and every 20-22 days until the end of the experiment. Cows were bled via jugular venipuncture every 28 days from Day -98 (Day 0 = calving) until Day 66. From Day 66 cows were bled every 7 days until the end of the mating period (Day 128). Concentrations of progesterone, non-esterified fatty acids and b-hydroxybutyrate acid and insulin were measured. Presence of corpus luteum (CL) was recorded and maximum follicle diameter was measured in all cows from the onset of the ST (Day 66) and during the following 4 weeks (until Day 94) in a weekly frequency. At Day 94, more cows (P < 0.001) in NP and in CR had CL compared with S cows (68, 57 and 21% for NP, CR and S, respectively). At that time, more cows in M-BCS presented CL than cows in L-BCS (77 vs 25; P < 0.0001). Within M-BCS, there were no differences in milk production between ST groups, while L-BCS cows with NP or CR produced less milk than S cows. Calf liveweight at weaning was 159.3 AE 3.1, 150.1 AE 2.9 and 147.0 AE 3.1 kg for S, NP and CR, respectively (P < 0.001). Suckling restriction with and without the presence of the calf had similar effects on reproductive performance, milk production and calf growth, while BCS interacted with ST to influence milk production. These results indicate that temporary suckling restriction could be an excellent management tool to increase reproductive performance of cows in moderate condition.

Effects of herbage allowance of native grasslands in purebred and crossbred beef cows: metabolic, endocrine and hepatic gene expression profiles through the gestation–lactation cycle

“…In agreement with previous results on beef cows (Quintans et al, 2010), although the magnitude of BCS losses during winter did not differ markedly among groups, the greater estimated energy intake and BCS for HI cows were correlated with greater serum insulin and IGF-I concentrations during the whole period evaluated. However, even though insulin decreased during winter for all cows, serum IGF-I concentrations decreased only for HI cows.…”

“…This would probably indicate a partial recovery of the energy balance in response to increased energy intake (90% to 110% of NRC requirements for lactation), as forage mass and height of native grassland increase as temperatures rise in spring. However, serum insulin and IGF-I concentrations continued to decrease with the onset of lactation, as has been previously observed in dairy and beef cows (Lucy, 2008;Quintans et al, 2010), suggesting that nutrients might be partitioning toward the mammary gland for milk production (Bauman, 2000).…”

“…Data and sample collection BW (after 12 h off pasture) and body condition score (BCS, scale 1 to 8, determined by the same observer throughout the experiment; Quintans et al, 2010) were recorded, and blood samples were collected from May 2009 to January 2010, at − 165, − 135, − 105, − 75, − 45, − 15 ± 10 and +15, +30, +45 and +60 ± 3 (mean ± s.d.) days relative to calving (days; average calving date: November 13).…”

“…Calf weight was determined at birth, and average milk production during the first +60 days of lactation was estimated by two measurements at +31 and +55 ± 6 days using a milking machine according to Quintans et al (2010). Commencement of luteal activity was defined as the day from calving to the presence of corpus luteum.…”

“…During periods of negative energy balance (NEB), as it typically occurs during the last few months of pregnancy and early lactation in spring-calved beef cows on native rangelands (Quintans et al, 2010), the liver plays a key role in the metabolic adaptation. Through the coordination and interconversion of nutrients, the liver works to re-establish metabolic homeostasis to ultimately support pregnancy and/or milk production (Bell, 1995;Bauman, 2000).…”