摘要:

Two silages of contrasting protein content were compared in a 16‐week winter‐feeding experiment with 12 Ayrshire cows. One silage contained 8.2% DCP in its DM and the other 15.9% DCP. The silages were fedad lib. with a supplement of either barley or barley plus groundnut cake. The DM digestibilities of the low and high protein silages were 74 and 67%, respectively, and the calculated S.E.s 56 and 47. Silage and total DM intakes were highest in the treatments containing low protein silage and in those containing groundnut. The mean daily milk yields for the treatments with and without groundnut were 35.4 and 32.s5 Ib (16.1 and 14.8 kg), respectively, with the high‐protein silage, and 38.1 and 35.0 Ib (17.3 and 15.9 kg) with the low‐protein silage. The S.N.F. contents of the milk were low and averaged 8.26 and 8.34% on the high‐ and low‐protein silage treatments, respectively, and were not affected significantly by the supplements. It is concluded that the low‐protein silage was superior to the high‐protein silage as a feed for cows, and that the digestibility of the silage DM was a truer indication of quality than

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01068.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

A report is presented on studies on the relationship betweenin vitrodigestibility of 18 silage samples and theirin vivodigestibilities. Various analytical techniques are compared and the method adopted, on grounds of suitability for routine operation and accuracy of prediction ofin vivodata, 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 ofin vitrol in vivorelationships is considered and a bivariate regression plane is proposed.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01069.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Silage was made from wilted and unwilted grass in May 1965, 1966 and 1967. The silage was made in sealed silos, but these were not evacuated and additives were not used.The silages were fed as follows: in 1965 to milking dairy cows and 1‐year‐old beef steers; in 1966 to steers coming into the experiment at 3, 9 and 15 months of age; in 1967 to weaned steer calves, with or without rolled barley (1 or 2 kg/head per day). In all years the silages were of highin vivodigestibility. The intake of wilted silage was higher than that of unwilted silage. There was no significant difference between the milk yields of cows fed on wilted and unwilted silage only. Liveweight gains were higher with wilted silage in 1965 and 1966, but not in 1967. In 1966 gains increased with age of animal and in 1967 gains were higher at successively higher levels of concentrate feed

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01070.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

The data from all published results of grazing trials in which three or more rates of stocking were compared for one or more years were examined. Where possible regression equations and correlation coefficients were calculated. In many cases, a significant negative correlation was found between stocking rate per acre and live‐weight gain per animal per day. In no case was the relationship positive, and no point of discontinuity was found in the linear relationship. The slope of the line appeared to be related to the length of the grazing season; the longer the season, the steeper the slope. The application of these results in practice is discussed in agronomic and economic term

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01071.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Production of dry matter by swards of ryegrass and cocksfoot varieties in winter and spring is dependent on a number of growth processes, each with different environmental requirements. Growth in the strict sense with the production of new leaves has been found to continue throughout the winter in Aberystwyth, although the rate of production fell very low during periods when the mean air temperature approached freezing, especially in cocksfoot varieties.Because of the ceiling set by the natural balance between leaf death and leaf formation, net increases in weight of above–ground parts in undefoliated plants may not occur for extended periods during winter. When, however, tiller numbers start to increase, or the ceiling is raised by an increase in size of tillers, dry–weight increases can come about. The extension of leaves and intern odes in spring, measured in terms of sward height, seems to be largely governed by flower initiation. A certain degree of extension was found to be present before this in an Algerian type.Practical distinctions between early and late types, which are based on flowering dates or sward height, or on parameters influenced by these characters, are not associated with similar differences in production of above–ground parts. These distinctions do not, therefore, permit a completely full and accurate picture to be obtained of winter– and spring–growth potentials in different

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01072.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Individual tillers of S23 ryegrass, in three paddocks set‐stocked with sheep at widely differing grazing pressures, were marked and studied from 11 July to 19 August, 1966, and observations were made on the frequency and severity of grazing.The uprooting of tillers, and the destruction of others, were major sources of loss of records. It was found that an acceptable measure of the frequency of defoliation could be made by recording three times a week. In a subsidiary experiment it was shown that repeated handling did not affect the DM yield, the number of tillers or the length of green leaf (G.L.L.) of single plants.Despite the extreme differences in grazing pressure, there were no significant differences between paddocks in the daily increase in the G.L.L. of tillers which were not grazed during a short period of intensive recording. In all three paddocks the sheep tended to graze the tillers with the greatest G.L.L. at any one time, and there was evidence of patchy grazing only at the lowest grazing pressure.An increase in grazing pressure resulted in increases in both the frequency and severity of defoliation. Comparisons were made between the product of the frequency X severity of defoliation of individual tillers, and the stocking rate, grazing pressure and herbage consumption on the three paddock

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01073.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

A simple test is described for screening lucerne seedlings for resistance toVerticilliumwilt. The test is sufficiently precise to distinguish the most resistant plants within a population possessing a fairly high level of resistance. Some results are presented illustrating the progress in breeding for resistance.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01074.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

In vitrodigestion of grass samples has shown that the amount of digestible cellulose, hexosan or pentosan is not greatly affected by species or by stage of maturity. A survey of published data on crude fibre and cellulose digestibility has confirmed these findings. Marked differences between grasses and legumes were observed. The rate of digestion has also been shown to be independent of the total amount of structural material present. The relevance of these observations to the selection of herbage varieties with greater intake by ruminants is discussed.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01075.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Thein vitroDM digestibility of four tropical pasture species,Cenchrus ciliaris, Chloris gayana, Digitariaspp.,Setariaspp. and one temperate grass,Lolium perenne, were studied, using the method described by Tilley and Terry (13).In vitrodigestibility was affected by fineness of grinding, sample size, pH of original rumen fluid and size of rumen fluid inoculum. Different relations were found between thein vivoandin vitroresults for the five species, with a maximum predicted difference of 3–5 digestibility units.It was considered that thein vivodigestibility of tropical grasses could be accurately predicted by this method, provided that the procedure was standardized and samples of knownin vivodigestibility similar to those being tested are included in each ru

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01076.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Herbage of very low quality forms the main diet of ruminants on the semi‐arid grasslands in the tropics for several months of the year. The grasses available have a high content of dry matter and crude fibre, a low digestibility and a very low crudeprotein content. Ruminants are unable to eat enough herbage to supply the nutrients required for their body functions and it is this inadequacy which is the major factor limiting animal production from semi‐arid grasslands in the trop

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1969.tb01077.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY