Late-cut Silage Research Articles

The nutritive value of silages. Digestion of nitrogenous constituents in sheep receiving diets of grass silage and grass silage and barley.

1. Two experiments were conducted to study the digestion of nitrogenous constituents in the rumen, small intestine and caecum and colon of sheep given diets of grass silage or grass silage and barley. Three silages were used. One was made from first-harvest grass in the spring and the other from regrowth grass cut in either early autumn or late autumn. All were of perennial ryegrass (Lolium perenne) and were preserved with formic acid. 2. Expt 1 involved a comparison between the spring silage given alone (644 g dry matter (DM)/d) and the spring silage supplemented with barley (151 g DM/d). The intakes (g/d) of total nitrogen for the silage diet and for the supplemented diet were 14.89 and 17.36. Corresponding values (g/d) for N passage were 15.55 and 18.53 (P < 0.01) and the duodenum, 6.01 and 7.09 at the ileum and 5.06 and 5.52 in the faeces. The barley supplement had no significant (P < 0.05) effect on rumen ammonia-N concentration. 3. Expt 2 involved a comparison between the two autumn-cut silages each offered at a level of feeding of approximately 700 g DM/d. The intakes (g/d) of total N for the early-cut silage and for the late-cut silage were 21.67 and 15.62 respectively. Corresponding values (g/d) for N passage were 17.10 and 16.96 at the duodenum, 6.65 and 6.80 at the ileum and 4.5 and 5.22 in the faeces. The concentration of NH3-N in the rumen was significantly (P < 0.001) higher with the early-cut silage than with the late-cut silage. 4. In both experiments the rates of bacterial crude protein (N x 6.25) synthesis in the rumen, estimated using alpha, epsilon-diaminopimelic acid as a marker, were low, 142 and 161 g crude protein/kg organic matter apparently digested in the rumen for the spring silage and the spring silage and barley diets respectively, and 68 and 103 g crude protein/kg organic matter apparently digested in the rumen for the early-cut autumn silage and the late-cut autumn silage respectively. For all diets there was a relatively low contribution of bacterial crude protein to the duodenal passage of crude protein and the amounts of individual amino acids ingested in the diets had a marked influence on the amino acids passing to the duodenum and as a consequence on the mixture of amino acids taken up from the small intestine. 5. The results are discussed in relation to the nutritive value of silage N for ruminants.

Influence of Stage of Maturity at Harvest and Level of Grain Feeding on Intake of Wheat Silage

Four silos of wheat silage were used to measure the influence of stage of maturity at harvest and level of grain feeding on total dry matter and energy intake. Silage 1 (early heading) was fed to milking cows, Silages 2 (early heading), 3 (milk stage), and 4 (dough stage) were fed to dairy heifers. Intake of the early cut silages was superior to the late cut silages when fed as the only feed. This superiority was retained when 20, 35, and 50% of the silage dry matter was replaced with a grain mixture.

Comparative Feeding Value of Oat-Pea Forages Ensiled at Two Stages of Maturity1,2

Oat-pea forages were ensiled directly from the field at either early-head or late-milk stages of oat maturity during 1963, 1964, and 1965. Each year the silages were fed to two groups of five lactating dairy cows in a switchback design based on three 28- to 35-day periods. Ad lib. silage intake, significantly greater for early-cut silage on an as-fed basis (p<1%), was not significantly different for the two silages on a dry matter basis. Although daily FCM was significantly greater on the early-cut silage during the 1964-65 feeding trial (p<5%), differences were never greater than 0.3 kg/cow/day during any one of the three trials. Live weight changes were more favorable for late-cut silage during the first and third feeding trials and for early-cut silage during the second. Analytical values, which were more propitious for early-cut silage, were not reflected unequivocally in the feeding trials.