Protein and glucogenic precursor supplementation: A nutritional strategy to increase reproductive and economic output1

Abstract

Reproductive performance in young beef cows is often compromised due to a mismatch of physiological demands and suboptimal environmental conditions. Studies conducted at the Corona Range and Livestock Research Center from 2000 to 2007 evaluated 3 postpartum supplement strategies that varied in the amount of glucogenic potential (GP) supplied. Reproductive variables, milk production, and serum metabolites were used to assess supplement effectiveness and economics associated with 2- and 3-yr-old beef cows (n = 379) grazing native range. Supplements were individually fed twice/week at 1,135 g/d (2003 to 2004) or 908 g/d (all other years) and provided 1) 327 g of CP, 109 to 118 g of RUP (CON); 2) 327 to 341 g of CP, 142 to 157 g of RUP (RUP); or 3) 327 g of CP, 151 to 173 g of RUP + 40 to 100 g of propionate salt (PS; RUP+PS). Ultimately, total GP for CON, RUP, and RUP+PS was 44 to 47, 57 to 70, and 93 to 141 g, respectively. Blood samples were collected once/week (2000) or twice/week (2001 to 2007) for progesterone analysis to estimate days to resumption of estrus. Cows were exposed to bulls for 60 d or less, and pregnancy was confirmed by rectal palpation at weaning. Days to resumption of estrus after calving decreased linearly (P = 0.02), resulting in an increased pregnancy rate (P = 0.03) with increasing GP. Milk production exhibited a quadratic (P = 0.04) response to increasing GP, with cows fed RUP producing the most amount of milk. However, a linear decrease (P = 0.07) in days from BW nadir to estrus was found with increasing GP. Total kilograms of calf weaned per cow exposed for the supplemental year and subsequent year was increased linearly (P = 0.07) with increased GP. The improvement in pregnancy rate by supplementing RUP+PS resulted in an increase in total revenue of 18% compared with CON-fed cows and 9.5% compared with RUP-fed cows in the subsequent year after supplementation. These data suggest feeding young cows additional GP in the form of PS allows for partitioning of nutrients away from milk production and toward reproduction, allowing for increased profitability by increasing pregnancy rates and decreasing days to resumption of estrus.

Intake of Medusahead by Sheep: Influence of Supplements, Silica and Individual Animal Variation

“…Dietary ingredients such as Ca propionate and yeast cultures (e.g., Saccharomyces cerevisiae fermentation products) may enhance medusahead intake and animal performance relative to the high-energy supplements previously studied. Propionate supplementation may improve ruminant nutrition when glucogenic precursors are inadequate due to low-quality diets and/or increased energy demands (Mulliniks et al 2011). Yeast cultures, on the other hand, increase cellulose degradation by rumen microbes (Williams et al 1991) and may increase medusahead use by grazing animals.…”

Circulating beta-hydroxybutyrate concentration may be a predictive measurement for young cows that have a greater probability to conceive at a fixed-time artificial insemination

“…On approximately d 58 postpartum, all cows were milked using a modified version of weigh-suckle-weigh by a portable machine (Porta-Milker; The Coburn Company, Inc., Whitewater, WI) as described by Mulliniks et al (2011). On the day of the milking, cows were gathered from their pasture and calves were removed.…”

BEEF SPECIES SYMPOSIUM: Potential limitations of NRC in predicting energetic requirements of beef females within western U.S. grazing systems1,2

“…Heifers were developed at a slow rate of gain (0.29 kg/d) on native dormant range with very little additional supplementation. In most years, cows received 100 kg·cow -1 ·yr -1 or less of supplement with the remainder of their diet consisting of native range (Mulliniks et al, 2011(Mulliniks et al, , 2013. Cows could be characterized as low milking (<7 kg/d), thin BCS (4.5), and moderate mature size (~556 kg) and weaned moderate-sized calves (~253 kg/cow).…”

“…However, when the environment (i.e., forage quality) was dynamic and heifers exhibited compensatory growth, the actual and 1996NRC-predicted responses were not in agreement. Under the same environment (i.e., forage quality) and nutritional management scheme (Mulliniks et al, 2011), 1996NRC models predicted that 2-and 3-yr-old cows would lose (P = 0.01) more BW during early lactation until breeding compared with actual BW performance. However, 1996NRC did predict similar (P = 0.33) ADG from breeding to weaning compared with actual performance.…”