Affiliation:
1. United States Department of Agriculture, Agricultural Research Service, Southern Plains Range Research Station, Woodward, OK
2. United States Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Center, Grand Forks, ND
Abstract
ABSTRACT
Two experiments were conducted to evaluate the efficacy of mineral supplementation to cattle grazing winter-wheat pasture. In experiment 1 (fall), 120 steers and heifers (body weight [BW] = 232 ± 11.4 kg) were assigned randomly to four blocks of replicated pastures during the second week of November in 2008 and 2009 and all herds (6 animals/pasture; 4.9 ha/pasture) were allowed to graze for 84 d. In experiment 2 (spring), 216 steers (BW = 248 ± 7.9 kg) were assigned randomly to five blocks of replicated pastures during the second week of February in 2009 and 2010 and all herds (12 or 6 animals/pasture; 4.9 ha/pasture) were allowed to graze for 84 d. Half the pastures in both experiments received a free-choice mineral mixture (Wheat Pasture Pro; Land O’Lakes Purina Feed, LLC; St. Paul, MN; Ca, 16% and P, 4%); mineral feeders were weighed weekly to determine mineral intake. All pastures were planted in early September of each year (67 kg of seed/ha) and fertilized with 50 kg of urea-N/ha. Standing herbage dry matter was determined midway between weigh dates by clipping wheat forage to the ground along 122 cm of drill rows at 10 locations/pasture. Data were analyzed by ANOVA, with treatment as the fixed effect and pasture, animal sex (experiment 1), and block as random effects. In experiment 1, cattle offered minerals had a 43% faster average daily gain (ADG; P = 0.02, 0.73 kg) than cattle not offered minerals (0.51 kg); hence, supplemented cattle weighed 6% more (P = 0.04; 286 kg) after 84 d than nonsupplemented cattle (271 kg). In experiment 2, cattle offered the mineral supplement had a faster ADG (20% increase; P = 0.04; 1.00 kg) than cattle not offered minerals (0.83 kg). Further, supplemented cattle weighed 4% more (P = 0.03; 326 kg) after 84 d than nonsupplemented cattle (312 kg). In both experiments, daily standing herbage dry matter averaged 1,381 kg/animal and never differed (P ≥ 0.47) between treatments. Mineral intakes averaged 135 (experiment 1) and 124 (experiment 2) g/d, resulting in a cost of supplement to kilogram of added BW gain of $0.53 and $0.64, respectively (assuming a mineral cost of $0.88/kg). Overall, supplementing an appropriate mineral mixture to cattle grazing winter-wheat pasture increased ADG in a cost-effective manner.
Publisher
Oxford University Press (OUP)
Subject
General Veterinary,Animal Science and Zoology
Cited by
5 articles.
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