The feed intake of milk cows I. Intake of winter rations during pregnancy and lactation and the influence of change to pasture

Abstract

SUMMARY1. For 4 weeks before calving in December or January a group of 7 Ayrshire cows each received daily 6 lb. hay and silage to appetite, whilst a second group of 9 received the same roughages and 6–10 lb. concentrates. After calving, cows from both of the pre-calving treatments were placed in each of two post-calving groups of 8 cows. A High treatment received approximately 8 lb./day more concentrates at the same milk yield than the Low treatment. Both groups continued to receive 6 lb. hay/cow/day and silage to appetite. The cows were allowed to graze by day from 21 February and by day and night from 13 April. Hay, at 5 lb./cow/day and reducing rates of concentrates were offered until 8 May.2. Individual feed intakes were estimated from faecal output and digestibility. Direct measures of the intakes of different treatment groups on indoor feeding agreed fairly closely with the mean individual estimates.3. The digestible organic matter intake (DOMI) of 1,300 lb. cows in the last stages of pregnancy was increased from 10 up to 14–16 lb./day by giving 8–10 lb./day concentrates. Immediately after calving, the increases in DOMI compared with pre-calving levels were about 2.5 lb./day for cows which received concentrates before calving and 8.5 lb./day for cows which received no concentrates before calving.4. When all cows had calved and were in full milk production there were no significant differences in DOMI, milk yield or rate of live-weight gain attributable to pre-calving treatment. Mean DOMI on the High and Low post-calving treatments were 23.8 and 19.4 lb./day, mean fat-corrected milk yields 44.5 and 38.8 lb./day and mean rates of live-weight gain 05 and nil lb./day, respectively.5. DOMI increased by 0.7 and 4.9 lb./day for High and Low post-calving treatments when cows were turned out to night as well as day grazing, and milk yields increased by 1.0 and 2.2 lb./day respectively.6. Regression equations relating animal production and feed intake, and substitution rates of concentrate usage were calculated. Faecal output and DOMI were closely related to milk yield. When additional concentrates were given the resulting increase in total DOMI was greater when the bulk feed was of low digestibility than when it was of high digestibility.

Studies on feed intake and feed utilization by sheep. II. The utilization of feed by ewes

“…The difficulty of getting representative samples for fat analyses may be the main explanation of the slightly lower correlations between intake and energy yield, compared to milk yield. This was also noted with cows by Holmes et al (1965).…”

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

“…The regression equations and correlation coefficients relating faecal output and DOM intake to animal production followed trends similar to those reported by Holmes et al, 1965, although milk yield, weight and weight gain accounted for a lower proportion of the total variance. This is possibly because in this experiment, with 16 cows and limited assistance available, Cr 2 O 3 was administered in suspension in oil and not as Cr 2 O 3 paper (cf.…”

Prediction of the voluntary intake of food by dairy cows: 1. Stall-fed cows in late pregnancy and early lactation

“…These factors include measurements which reflect energy expenditure such as milk yield, live weight and live-weight gain (e.g. Wallace, 1956;Holmes, Jones, Drake-Brockman and White, 1965), together with assessments of feed quality such as hay/concentrate ratios or digestibility (Conrad, Pratt and Hibbs, 1964) or weights of concentrates offered (Davenport, 1964;Johnson, Trimberger, Wright, Van Vleck and Henderson, 1966).…”