Silage and milk production: a comparison between four rates of groundnut cake supplementation of silage of high digestibility

Abstract

Grass silage made in late May from S24 perennial ryegrass was offered to twelve Ayrshire cows in a 16-week feeding experiment. The silage had a DM content of 25-3%, a pH of 3-91, and contained 16-8% CP and 68-4% digestible organic matter in the DM. The silage was fed ad libitum and was the sole feed in the control treatment. In the other three treatments the silage was supplemented with a cube offered at rates of 0 8, 14 and 20 kg per 10 kg milk. The cube contained 82 2% groundnut, plus molasses and minerals, and had 37-9% CP in the DM. The daily intake of silage DM was 11 4 kg per cow on average over the four treatments which did not differ significantly. The mean daily milk yields were 14-8 kg per cow in the control treatment, and 16-5,18-2 and 18 4 kg in the 0 8,14 and 2 0 kg supplement treatments respectively. The SNF, CP and lactose contents of the milk were Wghest on the 14 kg supplement treatment. It is concluded that with a high digestibility silage, there is little evidence to support the feeding of more than 1-4 kg of highprotein cubes per 10 kg milk in the declining phase of lactation.

Maize silage with a non‐protein nitrogen additive as feed for autumn‐calving cows

“…In vitro D-values were determined by the method of Tilley and Terry (1963) while cows on treatment A received only barley as a supplement. Thus their intakes of digestible CP were markedly lower than those of cows on treatments B and C. This failure to respond to additional digestible CP is difficult to explain, particularly in the light of the recent work of Castle et al (1977). It should be noted, however, that the milk protein concentration and the rate of liveweight gain of cows on treatment A were lower that those on treatments B and C. This suggests that body reserves may have been mobilized to meet the N deficiency .…”

Silage and milk production: a comparison between additives for silage of high digestibility

“…The highest temperature, 26°C, occurred in silage treated with formalin-acid at 2-0 1 t"', but in general all silages had a relatively cold fermentation. Maximum temperatures in previous silages of high D-value were somewhat lower at 19-23°C (Castle and Watson, 1975;1976;Castle et al, 1977); this difference may be attributable to the larger silos used previously compared with the experimental silos holding only 45 t. Other similarities between the three silages were in the DM concentrations, D-values and crude protein concentrations. The concentration of NPN expressed as a percentage of total N was 43% in both the formic acid silage and the formalin-acid silage treated at the 4-4 1 t"' rate; thus the additive treatment was not affecting the relative amounts of true protein.…”

“…The total requirement of ME, calculated from milk yield, milk composition and liveweight change (Ministry of Agriculture, Fisheries and Food, 1975), was similar for the three silages although the proportion contributed by each factor varied between the silages. The mean daily yield of milk from all three silages averaged 141 kg per cow which compares favourably with a daily yield of 14-6 kg per cow in the last 3 years (Castle et al, 1977).…”

“…Similarly, such studies could help to explain the overall response to the highprotein supplement. The addition of the supplement did not depress the intake of silage and the problem of the interaction of energy and protein has been discussed previously (Castle et al, 1977). Since the intake of DCP expressed as a percentage of the cow's requirements varied from 80 to 87% on the silage-only treatments, a similar limitation was imposed on the N intake of all the animals.…”

“…In planning experiments to compare silage additives, two requirements are crucial-first, the choice of the rates of application and, second, the accurate application of the predetermined level of the additive in the field. The choice of a rate of 2-0 1 t"' formic acid was based on experience in two previous experiments (Castle and Watson, 1976;Castle et al, 1977), when grass silages of high digestibility were ensiled successfully with application rates of 1-9 and 2-1 11"'. In previous work with formic acid (Castle and Watson, 1970a;b;1973) a rate of 2-211"' was used, but the lower rate was selected in the present experiment as conditions for wilting the crop were ideal.…”