Ruminal flora studies. VIII. The influence of rate and method of feeding a ration upon its digestibility, upon ruminal function, and upon the ruminal population

Abstract

A single ration made up of commercial sheep cubes (20 per cent. protein) together with oaten and lucerne chaff was fed to five sheep in five different ways. A Latin square design was used. Measurements were made on the ruminal population, the metabolism within the rumen, and the overall nitrogen balance and dry matter digestibility. Each of the different treatments resulted in a distinctive pattern in the ruminal population, pH, ammonia nitrogen, and volatile fatty acid levels. There were significant differences in dry matter digestibility and nitrogen retention. The daily ration given as a single feed gave the lowest dry matter digestibility and nitrogen retention. It also caused the greatest fall in pH values and bacterial counts, and the lowest protozoal counts. The highest ruminal ammonia nitrogen levels were also associated with this treatment. The best performance was obtained by feeding the concentrate in the morning and roughage in the afternoon, or feeding the whole ration in four equal portions at 2-hr intervals. The other two treatments – half ration morning and afternoon, or chaff in the morning and concentrates in the afternoon – gave intermediate results. Some implications of the various data are discussed, and the strong influence of feeding pattern is stressed.