Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2005
Publication Date: 6/3/2005
Citation: Looper, M.L., Aiken, G.E., Flores, R., Rosenkrans, C.F. 2005. Influence of nutrient supplementation on body weight and condition, and pregnancy of market beef cows grazing stockpiled and spring-growth tall fescue. Professional Animal Scientist. 21:225-231. Interpretive Summary: Knowledge of management practices to optimize value of market beef cows is limited, despite that fact that market cows may comprise as much as 25% of a beef operation's income. Breeding market cows may increase their value under present market conditions, consequently increasing the profitability of the livestock enterprise. In this study, market cows were supplemented with soybean hulls, corn:soybean meal, or not supplemented while grazing stockpiled and spring-growth tall fescue and exposed to bulls. Pregnant cows had higher selling prices than non-pregnant cows and the rate of pregnancy tended to be higher when supplements were provided. This information is of interest to beef producers, extension personnel, and agricultural professionals who advise beef producers on forage/animal management practices.
Technical Abstract: Seventy-five crossbred, non-pregnant beef cows (age = 4.5 ± 0.2 yr; BW = 395 ± 10 kg; BCS = 4.3 ± 0.2) were purchased from local auction barns during 2 yr to determine the effect of supplementation on body weight, body condition, average daily gain, pregnancy rate, and net income of market cows grazing stockpiled and spring-growth, endophyte-infected tall fescue. Cows were assigned to one of six pastures (two pastures/treatment per yr) of tall fescue for 160 (yr 1) or 147 (yr 2) d and one of three supplementation treatments: 1) soybean hulls (SH), 2) corn:soybean meal (CSB), or 3) not supplemented (control). Supplements were offered at 0.91 kg/d (as-fed) per cow. Cows were exposed to bulls and weighed and body condition scored (BCS) monthly. At the termination of the experiment, cows were palpated for pregnancy and sold at a local auction barn. Forage availability was not affected (P > 0.10) by supplementation and averaged 3637 ± 239 kg DM/ha throughout the grazing period. Supplementation did not influence (P > 0.10) ADG; overall, cows gained 0.47 ± 0.14 kg/d. Body condition gain was greater (P < 0.05) for SH cows than control cows. Cows supplemented with SH (493 ± 25 kg) or CSB (485 ± 25 kg) had heavier (P < 0.05) selling BW than control cows (462 ± 25 kg). Pregnancy rate tended to be increased (P = 0.10) for cows receiving CSB (96%) compared with control cows (74%). Selling price of pregnant cows was increased (P < 0.05) compared with non-pregnant cows ($694 ± 54 vs $524 ± 58, for pregnant and non-pregnant cows, respectively). Supplementation of market cows increased selling BW but did not affect net income. Pregnancy rate was increased in CSB cows, and selling price of pregnant market cows was greater than non-pregnant cows.