The effect of feed supplements on the yield and composition of milk from cows grazing good pasture

Abstract

SummaryTwo experiments are described in which spring-calved Ayrshire cows were fed supplementary food when grazing good, leafy pasture.In the first experiment 6 lb of a mixture of three parts bruised oats and one part flaked maize was fed daily to three groups of five cows. One group received the supplement from 1 July until 30 October, and the other two groups from 1 August and 1 September respectively. A control group received no supplement.In no month was there any statistical difference in daily milk yield between supplemented and unsupplemented groups of cows. The group fed from 1 July gave the highest total milk yield in the period June to October, but with a return of only 1 gal of milk from 34 lb of meal.The length of the lactation was not significantly affected by the treatment.In the second experiment, three groups of four cows on a 9-week change-over trial (4 May-5 July) grazed herbage containing an average of only 17·6% dry matter and 3·8% crude fibre. On the three treatments the cows ate pasture only, pasture plus 1·6 lb hay/day and pasture plus 5·7 lb of meal/day. The meal consisted of four parts by weight of undecorticated cotton cake, four of bruised oats and three of locust beans.Milk yield was significantly increased from 41·8 lb on the all-grass ration to 43·2 lb/day on the meal treatment but the hay did not affect milk yield.The fat content of the milk was significantly increased from 3·77 to 3·91% on the hay treatment, whereas the solids-not-fat content of the milk was not significantly affected by any of the treatments.At the present-day prices of the feeds and with cows on good leafy pasture it was clearly uneconomic to feed the meal supplements.

The Effect of Stocking Rate and Supplementary Concentrate Feeding on Milk Production

“…Experiments conducted at this Institute with dairy cows at pasture have shown that the feeding of concentrates increased the yield of milk slightly but decreased the profit per cow (2,3). Similar results were reported recently by Wood (10).…”

“…Our experiment has also provided additional information on the effect of supplements fed to cows on pasture at a high stocking rate. Previous experiments at this Institute and elsewhere (2,3,10) have shown that increases in milk yield as a result of feeding supplements to cows at pasture were small, but the results were generally obtained in conditions similar to those in treatment (A), the control. The response to the barley feeding in this experiment was better than that found in earlier experiments (2, 3) but it was still small.…”

Supplementary feeding of forage to grazing dairy cows

“…The effects of offering hay on milk production were in contrast to the work of Castle et al (1960) and Walsh (1969) who found that hay DM intakes of 1 -4-1-9 kg d"' in spring increased milk fat content but had no effect on milk yield. This reflected the changing partition of nutrients as lactation progressed.…”

“…There were, however, no significant effects on the yield of fat, protein or lactose. The effects of offering hay on milk production were in contrast to the work of Castle et al (1960) and Walsh (1969) who found that hay DM intakes of 1 -4-1-9 kg d"' in spring increased milk fat content but had no effect on milk yield. This probably reflects an increase in fibre intake rather than total DM intake, as the cows in those experiments were offered unrestricted grazing and were relatively low yielding (13-19 kgd"') In this experiment, where cows were higher yielding, both total DM and fibre intake were increased, resulting in increased milk yield and fat production.…”

Grassland Management and Milk Production at the Hannah Institute, 1958–62

“…During the grazing season the dairy herd received the minimum amount of supplementary feeding, as experimental work had shown clearly that with good grazing it was uneconomic to feed supplements (4,6). The only concentrates fed were cubes containing calcined magnesite in the first 4 weeks of spring grazing, and a mainly cereal mixture for steaming-up in the autumn.…”