Moss et al., 2000. Asian-Aust. J. Anim. Sci., 13 (Suppl.): 163-168

This study investigated the responses by dairy cows grazing Callide Rhodes grass (Chloris gayana cv. Callide) pasture to supplementation with barley or sorghum based concentrates (5 grain:1 cottonseed meal) or barley concentrate plus lucerne (Medicago sativa) hay. It was conducted in summer-autumn 1999 with 20 spring calved cows in 4 treatments in 3 consecutive periods of 4 weeks. Rain grown pastures, heavily stocked at 4.4 cows/ha, provided 22 to 35 kg green DM and 14 to 16 kg green leaf DM/cow per day in periods 1 to 3. Supplements were fed individually twice daily after milking. Cows received 6 kg concentrate/day in period 1, increased by 1 kg/day as barley, sorghum or lucerne chaff in each of periods 2 and 3. The control treatment received 6 kg barley concentrate in all 3 periods. Milk yields by cows fed sorghum were lower than for cows fed equivalent levels of barley-based concentrate. Faecal starch levels (14, 18 and 17%) for cows fed sorghum concentrate were much higher than those of cows fed similar levels of barley (2.1, 1.2 and 1.7%) in each period respectively. Additional supplementation as lucerne chaff did not increase milk yield. It is concluded that increased concentrate supplementation did not alleviate the problem of low protein in milk produced by freshly calved Holstein cows grazing tropical grass pasture in summer.