The feed intake of milk cows II. The effect of roughage quality during late pregnancy and lactation

Abstract

SUMMARY1. An experiment is described in which the individual feed intakes of 16 cows under winter housing conditions in yards, during the transition to spring grazing and on. summer grazing, were determined by faecal indexdigestibility methods. The influence of quality of feed before calving on intake and subsequent performance and the influence of pasture quality and availability on feed intake were included in the study.2. The provision of a diet of 67% organic matter digestibility, either as high quality hay or as low quality hay with concentrates, increased feed intake before calving when compared with a diet of low quality hay (digestibility 62%) alone. Compared with previous lactation yields the better diets were associated with the maintenance of milk yield, while the low quality hay diet before calving was associated with a 10%, but non-significant, reduction in milk yield.3. There was a marked rise in faecal output and digestible organic matter (DOM) intake after calving. During lactation, and especially on pasture, faecal output and DOM intake were both correlated with milk yield and metabolic live-weight. Total DOM intake was lower when the availability of feed was restricted and increased when feed was readily available; this increase was associated with a high maintenance requirement.4. When herbage with OM digestibility of 74–82% was consumed, faecal output rose with decreasing digestibility, but DOM intakes were relatively constant. Provided that efficient utilisation can be achieved, total utilisation per acre might be increased if herbage were grazed at the lower end of this range of digestibility.

Factors Influencing the Feed Intake and Liveweight Change of Beef Cattle on a Mixed Tree Savanna in the Transvaal

“…Good relationships are generally found between digestibility of feed and intake of ruminants (Holmes and Jones 1965), but Thomas and Campling (1976) concluded that at high levels of digestibility (over 70%), there may no longer be any relationship.…”

The influence of flexible and rigid grazing management and of supplementary feed on output per hectare and per cow

“…They had been sown in 1960 and 1962 respectively with the same grass seeds mixture of timothy (Phleum pratense), meadow fescue (Festuca pratensis) and white clover (Trifolium repens) and had both been grazed by dairy cows in previous years and used in experiments reported by Holmes and Jones (1965), Holmes, Jones and Adeline (1966) and Holmes and Curran (1967). Two adjacent pastures were used.…”

“…Residual SD ± 1-10 (2) When Y = digestibility of herbage organic matter (%) and X = nitrogen content of the faecal organic matter (%) For treatment RS, in which the cows received an appreciable proportion of concentrates in their diet, this method was inappropriate and the method of Holmes and Jones (1965) was adopted. This consisted of estimating the faecal output attributable to concentrates by assuming that the digestibility of the concentrate organic matter was 80%, and then applying the same digestion coefficient to the pasture component of the faeces as that adopted for the cattle receiving the corresponding pasture only (i.e.…”