STTMMARY. Seven changeover experiments were conducted to examine the effect of giving restricted amounts of concentrates on the voluntary intake of different roughages by non-lactating dairy cows. The addition of up to 6 kg concentrates daily to the diet of cows receiving roughage ad lib. caused little change in the intake of hay and a small increase in the intake of barley straw. Larger amounts of concentrates of 6 and 8 kg daily reduced hay intake by between 0-2 and 0-4 kg dry matter/kg concentrate dry matter given. When concentrates were given to the cows the rate of decline in intake of hay tended to be greatest with the hays of highest digestibility. The daily addition of up to 8 kg concentrates to the diet of cows offered silage ad lib. caused only small depressions in the intake of silage. The results are discussed in relation to recent work on this subject with cattle and sheep.

The dry-matter intake of silage was increased when the silage had a higher dry-matter content and when the time of access to the silage was increased from 3 to 24 h. Concentrate supplementation had a greater influence in depressing the intake of hay than that of silage. Only a small difference was observed in the replacement of hay by concentrates when the concentrates were given with two hays of different dry-matter digestibility. Concentrates with a relatively high protein content depressed roughage intake to a lesser extent than concentrates with a low protein content.

Lucerne was ensiled at various dry matter contents, within the range of 19·8% to 39·6%. An increase was found in lactic acid production, with a consequent decrease in volatile acid and volatile base content, up to the level of 33·9% dry matter. The dry matter intake of cows was increased by feeding silage with a high dry matter content.

The value of lacerating or chopping herbage for silage has been indicated by research work in this country and overseas. NASH (1) has shown that rather better silage can be made from high-protein grass lacerated before ensiling than from similar herbage to which has been added 20 Ib. molasses per ton. WOODWARD and SHEPHERD (2) noted that the less drastic treatment of chopping the herbage also had a beneficial effect on the quality of the silage; but it has been shown in laboratory expeiiments that, while crushed grass produced a bettei silage than unchopped material, the pH ofthe crushed silage was not always lowered to the level of 4-2 (DE MAN) (3). MARTIN and BUYSSE (4) in their experiments found that silage made from chopped lucerne had a lower pH and butyric-acid content and a higher lactic-acid content than that made from unchopped herbage.Even better silages have been obtained when the herbage was chopped with the addition of a carbohydrate-rich material. The 'Hardeland' method, where crushed beet is intimately mixed with chopped grass, has proved to be a reliable ensiling technique in Holland (KAPPELLE) (5).Wilting of the herbage before ensiling has been advocated in America, and results from experiments there show that, when the crop was ensiled at a dry-matter content of above 30 per cent, a good silage was produced (WOODWARD and SHEPHERD) (2). All the herbage was chopped before ensiling in these trials and the silage was under heavy pressure in the silos and, probably due to this, there was no difficulty in controlling the rise in temperature in the silage, even when the dry-matter content ofthe herbage was as high as 40 to 60 per cent. In small silos MARTIN and BUYSSE (4) found difficulty in preventing mould formation in wilted unchopjjed silage. It was also noted that the pH of wilted silage was higher than that made from herbage of a lower drymatter content, but in spite of this the butyric-acid content of the silage was low.In the trials to be described here the quality of silage made from lacerated, chopped and unchopped herbage has been compared. Wilting of the crop has also been tried, and the wilted herbage ensiled in a chopped and unchopped state. This was done with the object of comparing wilting as it would be done in Britain (ensiled unchopped) with the American method of the combined treatment of wilting and chopping. In addition, the value of adding molasses as the crop was chopped has been investigated. EXPERIMENTAL PROCEDURE The rate of fermentation in lacerated and chopped silageAs a preliminary to the main trials, a laboratory trial was conducted in 1952 to find the influence of laceration and chopping of herbage on the formation of acids in the silage. The herbage was predominantly a mixture of ryegrass, cocksfoot and clover, and when ensiled had a dry-matter content of 19 4 per cent and a crude-protein content of 16-5 per cent. The silage was sampled at intervals of 1, 2, 4, 7 and 14 days after ensiling, and the pH, lactic-acid and total volatile-acid content were determined on each...

SummaryIn a series of 3 trials there was little or no difference in milk yield when cows were fed the same quantity of dry matter in the form of well-preserved hay or silage from the same sward.A higher milk yield was obtained from silage made from grass at an early stage of maturity than from silage or hay made from the same crop 5 weeks later.In 2 trials when hay or silage was fed ad lib. the dry-matter intakes of the cows were higher with hay than with silage, and there was a consequent increase in milk yield and S.N.F. content in favour of hay.Some of the results indicated that with certain silages a depression in the S.N.F. content of the milk, due to a decrease in the casein content, could occur, although this was not associated with an inadequate energy intake.

Experiments with cows and sheep are described in which the voluntary intakes of hay and silage of differing digestibility were determined. The voluntary intake of hay increased consistently with increasing digestibility, but the relationship was not as well defined for silage. The addition of concentrates depressed the intake of hay, and this effect was more marked for hay with a high digestibility than with poorer quality hay. Concentrates appeared to depress the intake of hay by sheep more than by cows, an effect which was again more marked when the hay had a high digestibility value.

The roe deer belong to the markedly selective type of free-living ruminants and thus it is important to know the intake of individual feeds mainly in relation to the their quality. Little is known about the neurohumoral regulation of feed intake as well as about the passage of digesta in the guts. In the red deer the mean passage speed of digesta is twice as fast as that observed in domestic ruminants and it can only be supposed that this process is even faster in the red deer. Lochman (1975) stated the digestibility of organic matter, crude protein, fibre and nitrogen-free extract in meadow hay to be 56 and 38%, 37 and 31%, 57 and 31% and 57and 35% in roe does and bucks, respectively. At a body weight of 20 kg the daily dry matter consumption in the roe deer ranges from 0.4 to 0.8 kg. Dittrich and Groppel (1980) reported the weight of the rumen contents to be 8.71% of the body weight. Based on the analysis of the rumen contents Onderscheka (1976) found the nutrition of roe deer to be particularly rich in crude protein, with the proportion of sugar and starch being lower. According to Eisfeld (1974) the intake of 5 363 KJ of digestible energy was sufficient for a roe doe with the live weight of 20 kg. As for the available scientific literature it can be stated that very few experimental papers deal with the need and digestion of nutrients and exact experiments are missing at all. We can agree with Ellenberg (1978) that data on the need of nutrients so far obtained are very diverse and seem to be influenced by several known as well as unknown factors. The aim of our study was to determine apparent digestibility of nutrients in lucerne hay of different quality and in meadow hay from different high-quality sites. MATERIAL AND METHODS Metabolic experiments were carried out with 4 individuals of roe deer (Capreolus capreolus L.; 2 bucks and 2 does) in each group; the animals had a mean live weight of 19.4 kg (bucks = 20.8 kg, does 17.9 kg). The animals were weighed prior to the morning feeding at the start of the preparatory period and at the start and end of the experimental period. ABSTRACT: It was confirmed in metabolic experiments with 4 individuals of roe deer (2 males and 2 females with the live weight of 20.8 and 17.9 kg, respectively) that due to the animals' selective choice of a part of feeds there was no significant difference in the intake of lucerne hay of different quality and high-quality meadow hay (515.86 ± 66.97 and 597.82 ± 94.87 g, respectively). However, different quality of lucerne hay influenced the ani-mals' intake of crude protein and crude fibre. When the animals were fed meadow hay, they took in significantly less crude protein and fibre and significantly more nitrogen-free extract, fat and ash. Digestibility of crude protein was observed to be significantly decreased in hay of lower quality (by 10.1%). Digestibility coefficients for crude protein, crude fibre, organic matter and fat were significantly lower in grass hay compared to lucerne hay. Based on the coefficients of nutrient digesti...

Grass swards were cut at intervals of 2, 3, 4, 5, 6 and 8 weeks and received 336 or 673 kg ha "' nitrogen the higher level being applied as a single or as split dressings. Reducing cutting interval from 8 to 2 weeks reduced mean DM yield by 37X from 14 2 to90 t ha"'anddigestible DM yield by 24% from 9 4 to 7 2 t ha"'. The response to the extra N at the highest level of application was greatest under the most frequent cutting regimes. Application of N did not affect the digestibility of DM. Results are discussed in relation to the comparative effects of frequency of cutting at different seasons of the year and at different levels of N.