EFFECT OF GRAZING CYCLE ON MILK-PRODUCTION OF COWS ON KIKUYU PASTURE

Kikuyu pasture (Pennisetum clandestinum) was evaluated as forage for m ilk production during the 1985/86 and 1986/87 grazing seasons at the B athurst Research Station in the seaboard area of the Eastern Cape. The effect of different rotational grazing cycle lengths on milk producti on, body weight, herbage intake, digestibility and grazing time was in vestigated. Pastures were stocked at two Friesian cows per ha and graz ed for 1, 2 or 4-day periods of 15, 30 or 60 days rotation cycles, res pectively. Data were recorded during the grazing season which lasted f rom December to May each year. Milk (10.9 kg) and fat-corrected milk ( FCM; 10.1 kg) yields were highest (P less than or equal to 0.01) with the 30-day cycle. Neither butterfat (3.55 +/- 0.035%), nor protein (3. 19 +/- 0.022%) content of the milk was affected by rotation cycle. Mil k yield patterns showed a marked autumn slump with the 15-day cycle wh ile the other two cycles reflected a steady decline in milk production from 13.5 kg in December to 8.4 kg in May. Mean live body weight (550 .7 +/- 2.92 kg) did not differ between cycles but followed different p atterns during the growing season. Neither organic matter (OM) intake (14.2 +/- 0.188 kg), nor OM in vitro digestibility (56.3 +/- 1.07%) di ffered between cycles. OM digestibility decreased (P less than or equa l to 0.01) in all treatments from 67.6% in December to 44.7% in May. C ows in the 15-day cycle grazed longer (8.1 hours; P less than or equal to 0.01) per day to compensate for the lack of DM availability. Overa ll, the 30-day cycle proved to be the best grazing strategy for kikuyu pasture in this investigation.