THE USE OF SODIUM METABISULPHITE IN SILAGE MAKING

Three trials in which metabisulphite was used as a silage additive are described and the results discussed.
The data from two small-scale trials suggests that metabisulphite and molasses each have a similar effect on the quality of the silage produced, and that wilting appeared to be more effective than either of these two additives.
A comparison of silages in two large-scale trials indicates the necessity for uniform distribution of the metabisulphite.     

A COMBINATION OF NITRITE AND HEXAMINE AS AN ADDITIVE IN THE ENSILING OF HERBAGE

The development and testing of a new silage additive consisting of sodium nitrite and hexamine (hexamethylenetetramine) are described. The investigation was conducted over 8 years and consisted of 15 separate experiments with small steel cylinders and 13 with plastic sacks. The former were carried out with freshly cut blue lucerne and a storage temperature of 25°. When a mixture of sodium nitrite and hexamine was applied at the rate of 0.4% of fresh herbage weight, the quality of the resulting silage was superior to that made with commercial additives marketed in Sweden and the losses were considerably reduced.     

THE POTENTIAL VALUE OF SILAGE EFFLUENT AS A FERTILIZER

Results of the analysis for dry-matter, nitrogen and major base content of 9 silage effluents obtained from farm silos and 3 effluents from experimental tower silos are presented. The mean values obtained for the principal plant nutrients in the 12 effluents examined were 0·19% N, 0·037% P and 0·38% K. The results indicate that effluents may be a useful source of plant nutrients, particularly when undiluted with rainwater, and that, in general, silage effluents appear to be superior to liquid manure in manurial value.     

A COMPARISON OF THE YIELDS OF FORAGE MAIZE GROWN FOR SILAGE IN 1972 AND 1973 AT THE NATIONAL INSTITUTE FOR RESEARCH IN DAIRYING

The DM production from INRA 200, an early maturing hybrid maize grown for silage, was 10±6 and 14 5 t/ha in mid-October 1972 and 1973 (4±2 and 5±8 tons/ac). The plant population in both years was approximately 112,000/ha (45,320/ac). Whole-crop and cob DM percentages were 18±2 and 21±3 for 1972 and 39±9 and 53±0 for 1973, respectively. The cob yields were 49 and 10±4 t/ha (2±0 and 4±1 tons/ac) in 1972 and 1973 and cob in the two years accounted for 46 and 72% of total yield. At harvest the 1973 crop was 4–6 weeks more mature than the 1972 crop. These differences were attributed to the difference in accumulated temperature recorded from May till October, which was 567°C days in 1972 and 817 in 1973. Whole-crop DM content, yield of cob and yield of cob as a percentage of total yield were studied against seasonal temperature accumulation. In the case of DM percentage there was a highly significant linear regression which showed that 627°C days were needed to mature maize to 24% DM content.     

THE USE OF BARN-DRIED HAY AND SILAGE IN FATTENING YOUNG BEEF CATTLE

A series of trials was carried out in which barn-dried hay and silage were fed to young fattening cattle with or without supplementary barley. Liveweight-gains on silage and barn-dried hay alone were too low to provide an adequate finish during winter feeding. Liveweight-gains on hay alone were always higher than those obtained on silage alone, the difference being more marked in lighter animals. There was a marked response to supplements of 3 and 4 lb (1.4 and 1.8 kg) of barley, the response being significantly greater in silage-fed cattle than in those fed on barn-dried hay. There was some evidence of growth compensation with the introduction of a barley supplement to cattle on silage diets, but there was no such response in those fed on hay. Compensatory growth was not accompanied by improved digestibility or N retention.     

THE INFLUENCE OF SUPPLEMENTS OF FLAKED MAIZE ON THE DIGESTIBILITY BY STEERS OF SILAGE, FRESH LUCERNE AND LUCERNE HAY

Three experiments examine the effects of giving small supplements of flaked maize to steers on the digestibility and retention of nutrients from rations of grass silage, lucerne hay and fresh lucerne. The digestibility of the dry matter, crude fibre and crude protein of the silage ration was depressed by the successive additions of 1, 2 or 3 Ib flaked maize per day. There was a tendency for the steers to retain more nitrogen as the level of starch supplementation increased, in spite of a lowered crude-protein digestibility. The digestibilities of the constituents of lucerne hay and fresh lucerne were slightly increased by the addition of 2 and 4 Ib flaked maize per day. The reasons are discussed for the different effect of the supplemental starch on the digestibility of the crude fibre from grass silage and from fresh or cured lucerne. Attention is drawn to the increase in the retention of N following the supplementation of silage with starch.     

THE GROWTH OF BEEF CATTLE FED ON MAIZE SILAGE SUPPLEMENTED WITH DRIED LUCERNE, FISHMEAL OR UREA

Two experiments are reported in which 119 steers were fed ad lib. on maize silage, supplemented with different proportions of dried lucerne. In addition, the effect of including white fishmeal with the silage at levels up to 13% of the total diet was studied in one experiment. In another, the effect of adding urea to the silage (at 0.9% of the DM) was investigated. In hoth experiments the response in liveweight gain to increasing amounts of lucerne was curvilinear. The highest mean level of daily gain (1.5 kg/head per day) in the first experiment was achieved when the diet contained 62% lucerne or 13% fishmeal. In the second experiment the highest mean daily gain (1.1 kg/head per day) was achieved when the diet contained 71% lucerne. Daily liveweight gains were simOar for the cattle fed 25% of the diet as lucerne with sQage to which urea had heen added, and for those fed higher proportions of lucerne with untreated silage.     

PARTIAL WILTING OF GRASS CROPS FOR SILAGE

The possibilities of the wilting process have been investigated, with the ultimate object of determining its effect on the quality of farm silage. Attention has been confined mainly to mild or partial wilting, rather than severe wilting, since the danger of ensiling excessively dry material, especially when it is not chopped, is well recognised.
Preliminary field tests were conducted to determine the rate and extent of the fall in moisture content in long and in bruised herbage, wilted for periods not exceeding 24 hours. Subsequently the wilted silages were made in experimental silos and, finally, in trench silos on a farm scale. This first paper deals with the field trials. Results show that important reductions in moisture content can be obtained in all but very poor weather. In good weather, moisture content may easily fall from the 80% to the 70% level; in poor weather (cool, overcast, with occasional showers) moisture loss still occurs.     

THE RELATIONSHIP BETWEEN THE DM CONTENT OF HERBAGE FOR SILAGE MAKING AND EFFLUENT PRODUCTION

A study of 16 silages made at the Hannah Research Institute and 22 silages made at the Grassland Research Institute showed highly significant positive relationships hetween the DM percentages of the material ensiled and the resultant silage. Using regression equations derived from this data, and from a record of the presence or absence of effluent, it was calculated that the average minimum DM content of herbage for ensiling which would produce no effluent was 22.9%. To ensure a margin of safety against production of effluent, a minimum DM content of 24.7% in the herbage was calculated from the confidence limits. To obtain this DM content, herhage will normally require wilting; effluent production should then be negligible.     

PARTIAL WILTING OF GRASS CROPS FOR SILAGE

The aim of this part of the investigation was to test in practice, on a small scale, the partial-wilting method of making silage and to obtain data on quality, losses and digestibility of the wilted and un-wilted products. Wilting of grass/clover herbage was carried out for periods of up to about 24 hours and, on average, the moisture content was lowered by 6–4%, from 80–4 to 74.0%. All silages were well preserved, there was no overheating, the wilted products showed considerably lower nutrient losses than the unwilted silages and were not lower in digestibility. Mould formation was much more extensive in the top layers of the wilted silages, except when the wilted material had been bruised.     

PARTIAL WILTING OF GRASS CROPS FOR SILAGE

The aim of this, the final stage of the investigation, was to test the partial wilting process on a farm scale and to draw practical conclusions which might help farmers wishing to try it. Three important conclusions are drawn: (1) filling should be performed rapidly, (2) consolidation should be applied continuously, (3) sealing should be done immediately. Some overheating, a reduction in digestibility and considerable spoiling are likely to occur if herbage, wilted for much more than one day, is ensiled spasmodically with insufficient consolidation.
The wilting process is not foolproof and cannot be practised properly without giving great attention to detail, both in the field and at the silo. The method becomes a very much safer one when wilted and bruised, rather than wilted, long herbage is employed.     

AN INEXPENSIVE SEED CLEANER FOR USE WITH SINGLE HEADS OF TIMOTHY

Constructional details are given of an inexpensive seed cleaner capable of handling material from single heads of timothy, yielding cleaned seed of over 98% purity by weight. The conditions within the cleaner are reproducible and running costs negligible.     

THE USE OF LIGHT INTERCEPTION, GROSS MORPHOLOGY AND TIME AS CRITERIA FOR THE HARVESTING OF TIMOTHY, SMOOTH BROME AND COCKSFOOT

An experiment was designed to compare morphological development, light interception and time interval as possible criteria for the defoliation of timothy, brome-grass and cocksfoot. The morphological criterion included: (a) a first harvest before stem elongation and a second harvest after initiation of axillary bud development at the base of each tiller (b) a harvest immediately after stem elongation. Light was compared on the basis of 95 % and 80 % interception of the incident radiation by the foliage. Two-, 4- and 6-week intervals were used in the time series. Increased yields of up to 2600 lb DM/ac were obtained in timothy and bromegrass fertilized at 275 lb N/ac/yr when morphological treatment (a) was used in preference to (b); cocksfoot yields were not influenced. The greater the time interval between harvests or the greater the light interception before harvest, the greater was the yield. Advantages and disadvantages of the 3 criteria are discussed.     

THE ASSESSMENT OF THE NUTRITIVE VALUE OF SILAGE BY DETERMINATION OF IN VITRO DIGESTIBILITY ON HOMOGENATES PREPARED FROM FRESH UNDRIED SILAGE

A report is presented on studies on the relationship between in vitro digestibility of 18 silage samples and their in vivo digestibilities. Various analytical techniques are compared and the method adopted, on grounds of suitability for routine operation and accuracy of prediction of in vivo data, is based on analysis of homogenates of fresh silage. The homogenates, sufficiently uniform to permit of volumetric subsampling at acceptable error levels, are prepared in a new design of homogenizer. The impact of the % dry matter of the silage, as fed, on the accuracy of in vitrol in vivo relationships is considered and a bivariate regression plane is proposed.     

SILAGE AND MILK PRODUCTION. A COMPARISON BETWEEN BARLEY AND DRIED GRASS AS SUPPLEMENTS TO SILAGE OF HIGH DIGESTIBILITY

Grass silage made in late May from S23 perennial ryegrass was offered to 14 Ayrshire cows in a 16–week winter-feeding experiment. The silage had a DM content of 23.2% and contained 16–8% CP and 70.4% digestible organic matter in the DM. The silage was fed ad lib. as the sole feed in the control treatment, and supplemented with either barley or higuality dried grass cubes at the rate of 2, 3 and 4 kg/10 kg milk (2, 3 and 4 Ib/gal) in the other 6 treatments. The daily intake of silage DM was 11.6 kg/cow (25.6 lb) in the control, and significantly less in the supplement treatments. Silage intakes were higher in the dried grass than in the barley treatments. The mean daily yields of milk were 14.5 kg.cow (32.0 lb) in the control, 15.7, 16.6 and 17.0 kg (34.6.36.6 and 37.5 lb) in the barley treatments, and 17.8, 20.2 and 19.8 kg (39.2, 44.5 and 43.6 lb) in the drierass treatments, at the 2, 3 and 4 kg rates of feeding, respectively. The solidoat (SNF) content of the milk was lowest in the control treatment and highest in the drierass treatments. It is concluded that grass silage of high digestibility could be made successfully on a farm scale and that, with such a silage, a supplement of higuality dried grass was superior to a supplement of barley for milk production.     

THE EFFECT OF HISTAMINE ON SILAGE DRY-MATTER INTAKE

The oral introduction of 0·5 g histamine as the diphosphate into the rumen of sheep produced no effect on the physiological condition of the animals. The feeding of histamine, as the dihydrochloride, in levels up to 1 g/day to sheep on silage diets did not affect the dry-matter intake.     

THE INTAKE OF HAY AND SILAGE BY COWS

Three comparisons were made, with non-lactating fistulated cows, of the voluntary intake of silage and hay prepared from similar herbage. On average 28% more dry matter was eaten as hay than as silage. Silage and hay had similar digestibilities, but silage residues tended to remain in the gut longer than those of hay. The amount of digesta in the reticulo-rumen immediately after a meal ad lib . was greater with hay than with silage. The cows spent longer eating and ruminating per kg dry matter of silage than of hay. The results are discussed in relation to possible factors determining the voluntary intake of silage.     

THE USE OF GRAZING CONTROL FOR INTENSIVE FAT-LAMB PRODUCTION

Three grazing managements (set stocking, 4-paddock rotation, 8-paddock rotation), each with an undivided lateral creep area, were studied. Each of these managements carried 2 stocking rates (6 ewes and twin lambs per acre, 10 ewes and twin iambs per acre) and the sub-divided managements were grazed at 2 severities of grazing.
Stocking rate had a major effect upon the lambs' liveweights but did not significantly affect the ewes' liveweights. Lambs on set-stocking managements had a significantly higher rate of liveweiglit gain than lambs on managements with sub-divided ewe areas. Under lax grazing, for much of the experimental period, the lambs had a significantly higher rate of liveweight gain and the ewes had significantly higher liveweights than under severe grazing.     

THE USE OF GRAZING CONTROL FOR INTENSIVE FAT-LAMB PRODUCTION

A comparison of 3 systems of creep grazing, at a stocking rate of 6 ewes and 12 lambs per acre, indicated that lambs on a set-stocking management with a lateral creep area grew at a significantly ( P < 0·05) slower rate than lambs folded with a lateral creep area or those rotationally grazed with a forward creep area. A similar difference was apparent in the ability of the managements to maintain the ewes liveweights. However, it is suggested that these results were not the direct outcome of the applied treatments per se . Parasite burdens in the lambs were low on all the treatments and there were no significant differences between them.