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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #256175
Title: Protein and glucogenic precursor supplementation: A nutritional strategy to increase reproductive and economic output

Author
item MULLINIKS, J - New Mexico State University
item COX, S - New Mexico State University
item KEMP, M - New Mexico State University
item ENDECOTT, R - Montana State University
item Waterman, Richard
item VANLEEUWEN, D - New Mexico State University
item TORELL, L - New Mexico State University
item Petersen, Mark

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2011
Publication Date: 5/27/2011
Citation: Mulliniks, J.T., Cox, S.H., Kemp, M.E., Endecott, R.L., Waterman, R.C., VanLeeuwen, D.M., Torell, L.A., Petersen, M.K. 2011. Protein and glucogenic precursor supplementation: A nutritional strategy to increase reproductive and economic output. Journal of Animal Science. 89(9):3334-3343.

Interpretive Summary: A seven-year study was conducted to evaluate the effectiveness of range supplements when offered to 2 and 3-year cows on reproductive success and economic output. Three supplements supplied similar amounts of crude protein but differed in composition of ruminal protein degradability and glucogenic precursors. Calcium propionate was added in increase the concentrate of glucogenic precursors. Supplements were provided strategically based upon the onset of body weight gain when supplementation ceased. On average supplements were fed during a period of 10 to 70 days post partum. Days to resumption of estrus after calving decreased linearly (P = 0.02), resulting in an increased pregnancy rate (P = 0.01) with increasing supplemental glucogenic precursors. The improvement in pregnancy rate by supplementing the highest rate of glucogenic precursors resulting in an increase in total revenue of 15.3% compared to CON-fed cows and 7.2% compared to the intermediate rate of glucose precursors fed cows in the subsequent year after supplementation. These data suggest feeding young cows additional glucogenic precursors in the form of propionate salts allows for partitioning of nutrients away from milk production and towards reproduction, allowing for increased profitability by increasing pregnancy rates and decreasing days to resumption of estrus

Technical 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 precursors (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/wk at 1135 g/d (2003-2004) or 908 g/d (all other yr) and provided: 1) 327 g CP, 109 to 118 g RUP, 44 to 47 g GP (CON); 2) 327 to 341 g CP, 142 to 157 g RUP, 57 to 70 g GP (BP); 3) 327 g CP, 151 to 173 g RUP + 40 to 100 g of propionate salt (NutroCal, Kemin Industries, Inc.), 93-141 g GP (P). Blood samples were collected once/wk (2000) or twice/wk (2001-2007) 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 = 0.01) with increasing supplemental GP. Milk production exhibited a quadratic (P = 0.04) response to increasing GP, with cows fed BP producing the most amount of milk. However, a linear decrease (P = 0.07) in days from BW nadir to estrus was found with increasing consumption of GP. Total kg of calf weaned per cow exposed for the supplemental year and subsequent year was greater (P = 0.07) for cows fed P than the other supplements. The improvement in pregnancy rate by supplementing P resulting in an increase in total revenue of 15.3% compared to CON-fed cows and 7.2% compared to BP-fed cows in the subsequent year after supplementation. These data suggest feeding young cows additional GP in the form of propionate salts allows for partitioning of nutrients away from milk production and towards reproduction, allowing for increased profitability by increasing pregnancy rates and decreasing days to resumption of estrus. Key words: Beef Cow, Glucogenic Precursors, Supplementation, Reproduction.