S. J. Watson

The teart pastures of Somerset: I. The cause and cure of teartness

The scouring of cattle and sheep caused by the teart pastures of central Somerset is due to the presence of molybdenum in the herbage in amounts varying from about 20 to 100 parts per million in the dry matter. The scouring can be prevented and cured by feeding or drenching with copper sulphate. A daily dose of 2 g. copper sulphate for cows and 1 g. for young stock, is sufficient to cure and prevent the scouring on very teart land. Less copper sulphate may be enough on mildly teart land.

The chemical composition of grass silage

A short account is given of the main changes which take place during the ensilage process. Details are given of the methods of analysis used in examining samples of silage for p H, crude-protein, volatile base, amino acid, lactic acid, total volatile acid, acetic acid and butyric acid contents. The results of the examination of 293 samples of silage are discussed. Of these 258 were made from grassland herbage, 24 from silage crops, 9 from sugar-beet tops, and 2 from potatoes. The silages were made in towers, wood-lined pits, and a small number in stacks or clamps. The samples are divided up into those made by the ordinary process, with added molasses, with added whey, with moderate amounts of mineral acid with or without molasses, and with mineral acids added in amounts sufficient to bring the mass rapidly to a p H of 3·0–4·0—the A.I.V. process. For comparative purposes the silages made by these processes have been divided, within each process, into groups of varying p H. reaction.

Composition, digestibility and nutritive value of samples of grassland products.

The composition, digestibility coefficients and digestible nutrients of a large number of samples of fresh grass, silage, hay and artificially dried grass are tabulated. Curves have been prepared from these figures which enable the starch equivalent and protein equivalent to be obtained, by interpolation, from the value for crude protein determined by analysis. The method of calculating the starch equivalent of artificially dried grass from the data for digestibility and composition is discussed with particular reference to the fibre correction factor. It is considered that this should be the same as that used for the fresh grass prior to drying. A number of miscellaneous samples—mostly of home-grown foods—are included in the tables.

The losses of dry matter and digestible nutrients in low-temperature silage, with and without added molasses or mineral acids.

A series of experiments designed to measure the losses in dry matter and nutrients in different types of silage are described. These extend over a period of 4 years. The ordinary or low-temperature process (maximum temperature 80–100° F.) is described either with or without added molasses or whey solutions, and is compared with processes in which solutions of mineral acids are added. The A.I.V. process of Virtanen, in which the acidity of the mass is reduced rapidly to p H. 3·0–4·0 by the addition of a mineral acid solution, is considered in detail.

The time of cutting hay, and the losses entailed during haymaking

Experiments have been carried out from 1930 to 1935, to investigate the composition, digestibility and yield of meadow hay cut at a normal time, and also of hay cut some 3–5 weeks earlier. Due consideration has been given to the “aftermath” growth occurring on the areas cut for the early hay between the times of cutting of the early and ordinary hay. As was expected, the early hay, being less mature, was of better composition and digestibility than the ordinary hay. The average crude protein contents were 12·2 and 7·9 per cent of the dry matter respectively. The yield data, average of 5 years, are summarized below, stated as lb. per acre, the early hay values including the aftermath yields.