Performance of Fall-Calving Cows and Their Calves Grazing Fescue-Based Forage Systems

Abstract

Tall fescue (Festuca arundinacea Schreb.), a perennial cool season grass, is well adapted to a wide range of soil and climatic conditions. Stockpiled (accumulated growth) tall fescue has been grazed successfully by dry pregnant beef cows in winter, but stockpiled fescue use by lactating cows has not been reported. Twenty-four, 3-acre pastures stocked with 3 or 4 fall-calving cows and their calves were used in five grazing trials from 1980 to 1984. Four forage system treatments were evaluated: (System 1) ‘Kentucky 31’ tall fescue + red clover (Trifolium pratense L.) + ladino clover (Trifolium repens L.) with fall N fertilization and stockpiling; (System 2) Fescue + ladino and red clovers + ‘Kobe’ lespedeza [Lespedeza striata (Thunb.) H. & A.]; (System 3) Fescue + red and ladino clovers + a small creep pasture for the calves consisting of rye (Secale cereale L.) + annual ryegrass (Lolium italicum L.) + crimson clover (Trifolium incarnatum L.); (System 4) ‘Tifton 44’ bermudagrass Cynodon dactylon (L.) Pers.] + fescue + red and ladino clovers + N fertilization. Cows (Bos taurus) were purebred Angus with calves sired by Angus, Hereford, or Simmental bulls. Animals were allotted to systems at the end of the calving season (December) and removed in early July. When forage growth was inadequate to meet animal nutrient requirements, hay produced on the experimental pastures was fed. Calf 240-d adjusted weights and average daily gain (ADG) were similar among systems. There was no effect of genotype on calf performance. The ADG's of cows grazing Systems 1, 2, and 3 during 1980 to 1983 were 0.23, 0.18, and −0.05 lb/d, and those of cows grazing Systems 2, 3, and 4 during 1982 to 1984 were −0.05, −0.19, and 0.11 Ib/d, respectively. In System 3, calf creep pastures (17 to 25% of total) probably were larger than needed, and cow pastures were not large enough. Cow-calf pairs grazing System 1 pastures required less hay than those grazing Systems 2 and 3 in 1980 to 1983. Cow-calf pairs grazing System 4 pastures required more hay than those grazing Systems 2 and 3 in 1982 to 1984. Results from this study support using forage systems of fescue + clover + N for fall stockpiling, and of fescue + legumes, for maintaining performance of fall calving cows and their calves.