The effect of pre- and post-partum energy and protein supply on the performance of single- and twin-suckling beef cows and their calves

Abstract

1994). The effect of pre-and post-partum energy and protein supply on the performance of single-and twin-suckling beef cows and their calves. AbstractChanges in live weight, body condition, milk production and composition xvere monitored for single-and twinsuckling cows in two experiments. In experiment 1, all cows were managed for 3 months before calving to achieve condition scores at calving 2-1 (low) and 3-1 (moderate). Subsequently, these animals were placed on a fixed level of energy intake (80 M] metabolizable energy (ME) per day) for 16 weeks. Post-partum diets contained differing amounts of digestible undegradable protein (DUP), but similar amounts of effective rumen degradable protein (ERDP). In experiment 2, single-and twin-suckling cows were fed to achieve a condition score at calving of around 2-75. These animals were subsequently placed on two levels of energy intake (80 MJ and 130 MJ ME per day) during the first 16 weeks of lactation. The diets providing these energy intakes also contained differing amounts of DUP. Neither the level of DUP in the diet nor the level of feeding significantly altered the digestibility of the dry matter or organic matter in the dry matter of the experimental diets. Body condition at calving had little effect on daily milk yield (9-5 kg) and composition (33-5 g/kg fat; 30-0 g/kg protein) in experiment 1. Cows with higher body condition scores at calving lost 13-5 kg more live weight and 0-26 units more body condition (P < 0-05) during the 1st month post partum but remained in better condition throughout the trial period than cows with lower body condition scores. Cows on 130 M] ME per day produced higher (P < 0-001) daily yields of milk, milk fat and protein (+2-0 kg; +151 g; +85 g) and lost 57 kg less live weight and 0-52 units less body condition (P < 0-001) than cows on 80 MJ ME per day. Elevated dietary levels of DUP promoted (P < 0-05) daily milk yields (by 1 -25 kg) and reduced live-weight and body condition-score loss during the 1st month post partum in both experiments. Twin-suckling coivs produced the highest average daily yields of milk throughout the 16-week trial period in both experiments but yields were not significantly higher after early lactation in experiment 1. Cow body condition score at calving and the level of DUP in the post-partum diet of cows had no effect on the post-partum performance of calves. Twin calves had slower growth rates (P < 0-001) than single calves (0-65 and 1-07 kg/day respectively) in experiment 1. However, twin calves sucking cows on 130 MJ ME per day in experiment 2 grew similarly to single sucking calves from week 8 of lactation (0-8 kg/day).

Factors affecting the body condition score of N'Dama cows under extensive range management in Southern Senegal

“…In general agreement with other conclusions presented in the available literature, the BCS decreases in late pregnancy and in early lactation, then progressively returns to its initial value [37,41]. Under temperate climates, patterns of BCS variations during lactation are generally better explained by complementary information beyond lactation status and/or calves' growth and parity.…”

“…Moreover, it is well adapted to large-scale surveys with numerous data in an environment where animals are subject to large variations of body fat. Many authors have studied the effect of feeding level and the period since calving on BCS variations in cattle under either temperate [5,34,37,41] or tropical [9] climates. The general consensus is that BCS is particularly influenced by season and feeding.…”

Naloxone evokes a nutritionally dependent LH response in post partum beef cows but not in mid-luteal phase maiden heifers

“…From calving, cows were offered the same diets as in the studies reported by Sinclair et al (1994a). These diets were designed to contain differing amounts of DUP (14 v. 31 g/kg DM) but similar amounts of effective rumen degradable protein (ERDP; 100 v. 105 g/kg DM).…”