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A field trial was conducted to determine (1) the effectiveness of an anthelmintic program using morantel tartrate (MT) to control subclinical gastrointestinal parasitism among cattle on pasture and (2) the effects of the program on the performance of cattle. Two Hereford herds, each on a separate pasture with forage of comparable quality and quantity, were used. A stocking rate of .62 ha/cow-calf was maintained in both pastures. One herd consisted of 124 cows and 122 calves and served as a non-mediated control group. The second herd consisted of 126 cows and 124 calves. Cows and calves from the latter group were treated with a bolus formulation of MT at a dosage of 10 mg/kg body weight at the beginning of the trial and again 55 d later. Calves were treated again 42 d after the second treatment. Cattle were weighed individually each month and rectal fecal samples for nematode egg counts were obtained from 36 cows and 36 calves from each group at that time. These donor cattle were selected at random at the time of the first weighing; fecal samples were then obtained from the same animals throughout the study. Eggs of the Cooperia-Ostertagia-Trichostrongylus complex predominated in all fecal samplings. There was no difference in the number of nematode eggs from the two groups of cows. However, the medicated cows gained significantly more weight than the controls and had an average weight gain advantage of 28.8 kg. The medicated calves had significantly lower average egg counts and made higher weight gains than the unmedicated calves. The medicated calves had an average weight gain advantage over the control group of 11.1 kg.

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There is a lack of formation concerning the influence of sequential applications of similar nitrogen rates on tall fescue (Festuca arundinacea Schreb. ‘Ky 31’) forage production. The purpose of this study was to determine the influence of the application of 240 kg ha−1 N, in differing annual sequences, on forage production and quality. In general, forage production was highest in plots receiving high (> 120 kg/ha) N rates just prior to the spring (April–May) and/or fall (August and September) periods of growth. Total annual production was highest (9,645 kg ha−1) in plots receiving 240 kg ha−1 N as a single application in March. Plots receiving single N applications in September and November and semiannual N applications in July and January produced in excess of 8,000 kg ha−1 forage. The IVDMD varied only six percentage units for all treatments, was highest in plots promoting highest production during March and October, and was lowest in forage from the check plots (receiving no N). Frequent applications of N increased forage production during June and August when compared to total annual application of N in March. High N rates applied in July allowed for increased vegetation composition of invaders in plot areas and the highest IVDMD.

No abstract