Production from first-calf beef heifers fed a maintenance or low level of prepartum nutrition and ruminally undegradable or degradable protein postpartum

Abstract

Two experiments were conducted in consecutive years to determine the effects of prepartum nutrient level and postpartum ruminally undegraded protein intake on nutrient status, milk production, subsequent calf production, and reproductive performance of 126 crossbred, primiparous beef heifers. Prepartum treatments were low nutrient intake (LN) (approximately 2.5 kg of TDN, .5 kg of CP animal-1.d-1 and maintenance nutrient intake (MN) (5 kg of TDN, 1 kg of CP animal-1.d-1), which were fed for 75 d before parturition. Two postpartum protein supplements were formulated to provide 250 g/d of ruminally degradable protein (RD) and one to supply ruminally undegraded protein (UD) at 250 g/d of additional UD CP compared to the RD supplement. Cholesterol was lower (P less than .01) in heifers given UD than in heifers given RD. Blood urea nitrogen was higher (P less than .01) for UD-fed heifers than for RD-fed heifers and was higher in LN heifers (P less than .06) than in MN heifers. Milk production did not differ (P greater than .11) as a result of LN, MN, UD, or RD. Postpartum cow weight gain was greatest (P less than .01) for UD and LN heifers. The percentage of heifers bred during the first estrous cycle of the breeding season was greater (P less than .02) for UD than for RD. Overall, prepartum nutrition did not interact with postpartum protein supplement, nor did it have any effect on postpartum interval, whereas UD increased cow weight gain postpartum and reduced postpartum interval.

Early weaning in Northern Great Plains beef cattle production systems: II. Development of replacement heifers weaned at 80 or 215d of age

“…Hunter and Magner (1988) report that diets greater in rumen undegradable protein may stimulate insulin secretion due to continual flow of protein for absorption in the small intestine. These results also agree with previous studies where ruminal undegradable protein was offered (Lalman et al, 1993;Sletmoen-Olson et al, 2000;Waterman et al, 2006;Wiley et al, 1991). However, the response to insulin was not observed for heifers at the JG location.…”

Supplementation to meet metabolizable protein requirements of primiparous beef heifers: I. Performance, forage intake, and nutrient balance1

“…Twenty-four-hour milk production was determined by the weigh-suckle-weigh procedure; SEM = 0.6; milk production declined (P = 0.0005) across measurement dates. Similar to our results, Wiley et al (1991) showed that UIP supplementation to lactating cows increased postpartum BW change. These authors reported that UIP supplementation also increased the percentage of cows bred in the first 21 d of the breeding season.…”

“…Lactating 2-yr-old cows have a high requirement for MP relative to nonlactating cows (NRC, 1996). Supplementing UIP to young, lactating cows improved BW gain and the percentage of cows that bred early in the breeding season (Wiley et al, 1991). We hypothesized that meeting NRC (1996) MP requirements for lactating 2-yr-old cows would positively affect production traits.…”

Influence of post-calving supplemental protein on calf performance and reproductive efficiency for beef cows fed silage

“…In their study, cows grazing smooth brome (Bromus inermis) were supplemented with a highly undegradable protein supplement based on CGM and blood meal. Other research has observed a positive relationship between level of UIP and cow weight gain (Wiley et al 1991;Dhuyvetter et al 1993;Rusche et al 1993). However, in those studies energy intake of cows was restricted, either by limit feeding or by forage quality.…”

“…In our study, a decline in performance was not observed until predicted UIP values were somewhat higher, but our data are based on total, not supplemental, UIP. Wiley et al (1991) showed higher serum insulin concentration in cows fed a diet supplying high levels of UIP relative to a low UIP diet and postulated that this could partition more nutrients toward tissue deposition and away from milk production. Thus, the poor calf performance from cows fed high levels of CGM could be attributed to an insulin effect.…”