Effect of amount of oats and barley-oats on milk production

Feed tables give lower feed values for oats than for barley, but oats has been shown in many experiments to improve milk production and milk fatty acid composition compared with barley (Moran 1986, Heikkilä et al. 1988, Martin & Thomas 1988, Ekern et al. 2003). Oats has traditionally been used in Finland as a main cereal for dairy cows on farms. Today farmers often use barley-oats mixtures. In this experiment we studied the effects of increasing amounts (0.2, 0.3, 0.4 kg/kg 4-% fat-corrected milk) of oats and barley-oats mixture (1:1) as the only concentrate on the milk yield and composition and feed utilization in a 2 x 3 factorial continuous trial with 36 Finnish Ayrshire cows. Grass silage was fed ad libitum with hay 1 kg/d. An experimental period of 24 weeks was preceded by a 2-week covariance period. The digestibility of feeds was measured on sheep. Mean consumption of cereals was 4.8, 7.5 and 10.2 kg/d with respective proportions of 29, 40 and 51% of dietary dry matter (DM). Increasing the amounts of both cereals from 29 to 51% of DM decreased silage DM intake with a substitution rate of 0.438 and 0.264 for oats and barley-oats, respectively, but total DM intake, milk, fat, protein and lactose yields increased linearly. Oats resulted in higher milk yield response than barley-oats (0.966 vs. 0.745 kg milk/kg cereal DM increase), but the difference in energy-corrected milk yield response was smaller (0.846 vs. 0.781) because of a tendency to lower fat and protein content with increase of oats compared with barley-oats. The oleic acid content of milk fat tended to increase with increasing oats, but to decrease with increasing barley-oats. Milk renneting properties improved with increasing cereal amounts, but less with oats than with barley-oats. Milk production parameters did not differ significantly between cereals except the utilization of metabolizable energy and AAT (amino acids absorbed from the small intestine), which were higher with oats than with barley-oats as a concentrate. Ekern, A. et al. 2003. Acta Agriculturae Scandinavica, Section A, Animal Science 53: 65-73; Heikkilä,T. et al. 1988. Proceedings VI World Conference on Animal Production Helsinki 1988, p. 336; Martin, P.A. & Thomas, P.C. 1988. Journal of the Science Food and Agriculture 43: 145-154; Moran, J.B. 1986. Animal Production 43: 27-36.