THE NUTRITIVE VALUE OF WEEPING LOVEGRASS DURING THE SPRING SEASON

Faecal samples from a continuous digestibility trial with Eragrostis curvula were analyzed for cell-wall contents, acid-detergent fibre, lignin, asb and N. DM digestibility was regressed on all these fractions and organic-matter digestibility was also regressed on faecal organic-matter N. The best predictions of digestibility were obtained by the use of faecal lignin as a percentage of acid-detergent fibre, and by cell-wall contents. N was a comparatively poor predictor and it is shown that its relationship with organic-matter digestibility varies with the level of N in the diet. It is concluded that both lignin and cell-wall contents could serve as useful internal indicators since their use is unlikely to be biassed by metabolic and microbial contamination.     

THE RELATIVE PALATABILITY OF VARIOUS VARIETIES OF WEEPING LOVEGRASS (ERAGROSTIS CURVULA (SCHRAD) NEES)

It has been found for pasture purposes that the numerous varieties belonging to the species Eragrostis curvula can be grouped into types for which the names curvula, robusta blue, robusta green, robusta intermediate and chloromelas are proposed.
The relative palatability of 20 varieties of E. curvula , and 1 variety of E. plana, Chloris gayana and Digitaria smutsii were compared with one another. Chloris and Digitaria were found to be the most palatable. Of the Eragrostis varieties studied, the robusta green, robusta intermediate and robusta blue were the most palatable, chloromelas varieties and E. plana being intermediate and the curvula varieties the least palatable.
The grasses with the highest phosphate and potash contents were also those most acceptable to livestock. Results obtained from analyses suggested that crude fibre had little bearing on palatability.
The more acceptable grasses were also the more succulent.
No relationship between leaf structure and livestock preference could be demonstrated.     

THE NUTRITIVE VALUE AND AGRONOMIC ASPECTS OF SOME FODDERS IN NORTHERN NIGERIA

The results of digestibility trials are presented on Andropogon gayanus, Brachiaria brizantha, Chloris gayana (Rhodes grass), Cynodon dactylon (Bermuda grass), Hyparrhenia rufa (Janagua grass), Panicum maximum (Guinea grass), Pennisetum pedicellatum, P. purpureum (Elephant grass), unimproved bush grass, Centrasema pubescens (Centro), Desmodium scorpuris and Stylosanthes gracilis (Stylo). The nutritive values are discussed, together with agronomic aspects important in relation to the growth of these species in Northern Nigeria.     

THE NUTRITIVE VALUE AND AGRONOMIC ASPECTS OF SOME FODDERS IN NORTHERN NIGERIA

Digestibility data are presented on the following; Andropogon gayanus hay and bush foggage, Arachis hypogoea (groundnut) haulms, Glycine max (soya-bean) hay. Sorghum vulgare (sorghum) leaves and hay, Stizolobium sp. (velvet bean) hay, Vigna sinensis (cowpea) hay and haulms, and S. vnlgare/Stizolobium sp. mixture. The results are discussed from the agronomic aspect.     

THE NUTRITIVE VALUE AND AGRONOMIC ASPECTS OF SOME FODDERS IN NORTHERN NIGERIA

The results are presented of digestibility trials on silage samples made from the following materials: Andropogon gay anus, Chloris gayana (Rhodes grass), Hyparrhenia rufa (Jaragua grass), Panicum maximum (Guinea grass), Pennisetum pedicellatum, P. purpureum (Elephant grass). Sorghum vulgare (sorghum), Acanthospermum hispidum, Helianthus annuus (sunflower), Stizolobium sp. (velvet bean), Zea mays (maize) and mixtures of A. gayanus/P. pedicellatum, Arachis hypogoea (groundnut haulms)/ P, pedicellatum. Sorghum vtdgare/Stizolobium sp., Z. mays/Vigna sinensis (cowpea). The results obtained, also the agronomic aspects of the subject and the use of the materials as fodder for cattle during the dry season are discussed.     

A NOTE ON THE EVALUATION OF THE NUTRITIVE VALUE OF FORAGE CROPS BY THE ACETYL BROMIDE TECHNIQUE

It has been shown in the past that in vitro digestibility of forage crops could be accurately predicted by the acetyl bromide absorption technique. This note demonstrates that in vivo digestibility values can be accurately predicted by this method and that in this respect the method is comparable in accuracy with the in vitro digestibility technique.     

THE USE OF RUMEN-FISTULATED STEERS IN THE DIRECT DETERMINATION OF NUTRITIVE VALUE OF INGESTED HERBAGE IN GRAZING EXPERIMENTS

A rumen-fistulated steer was used for the manual collection of samples of freshly swallowed herbage, in a grazing-management experiment on a perennial ryegrass sward. Diurnal and seasonal changes in the in vitro digestibility of the herbage selected by the grazing animal were studied under both strip- and continuous-grazing methods of management.
There was no appreciable change in digestibility as the sward was grazed down from upper to lower layers under strip-grazing management in April and May. In June to October a within-day fall in digestibility was found, much of which was attributable to an increase in the amount of old dead herbage grazed from the lower regions of the sward. Dead herbage taken in by the grazing steer was considerably lower in digestibility in August than in May. The in vitro digestibility of herbage samples, cut to ground level before and after grazing in a strip-grazed treatment, fell markedly as the proportion of dead herbage in the sample increased, giving a high negative correlation.
In a continuous-grazing management there was no pattern of diurnal variation, and the seasonal variation in digestibility of the ingested herbage was less than in strip grazing. The implications of these results are discussed in relation to indirect methods of digestibility determination (faecal-index technique), the measurement of herbage intake, and to some aspects of grazing management.     

LOSSES IN THE NUTRITIVE VALUE OF HEAVILY-WILTED HERBAGE ENSILED IN EVACUATED AND NON-EVACUATED POLYTHENE CONTAINERS

A conservation experiment is described in which the losses entailed in ensiling heavily-wilted herbage of 37–43% dry-matter content either by complete sealing in polythene alone, or by complete sealing followed by evacuation of air, were investigated.
The metabolizable energy values of the grass and silages were determined, and the silage volatile-acids fraction investigated by gas chromatography. The results indicate that there are no significant fermentation differences between the two types of silage. The mean dry-matter loss for the sealed, unevacuated silos was 6.5% and for the evacuated silos 7.8%. These losses, and the individual crude- and digestible-nutrient losses, are discussed in relation to other published work.     

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.     

STUDIES ON THE EXTENSION OF THE GRAZING SEASON

In a small plot trial good yields of foggage of satisfactory botanical composition with cocksfoot dominant were produced from a mixed-species pasture after it had been cut for silage in spring and again in summer. Production in the following year was satisfactory. The advantages of using ordinary pastures for winter grazing, especially if this occurs only during their last winter before ploughing, are discussed. From a study of various autumn treatments it is concluded that the optimum management for foggage production in the north-east of Scotland is to close fields on or near 10 August when 3 cwt. nitro-chalk per ac. should be applied; a higher rate (6 cwt. per ac), though it increased yields and percentage crude protein immediately, and also during the subsequent summer, conferred no benefits of practical importance. Effects of K fertilizer applications were negligible. Closing as late as the beginning of September gave smaller but useful yields of a higher protein foggage and the sward was less cocksfoot-dominant. Autumn closing and fertilizer treatments did not affect foggage wastage during winter, which averaged 14 per cent of the initial organic-matter yield; the percentage of crude protein in standing foggage rose.     

STUDIES ON THE EXTENSION OF THE GRAZING SEASON

Foggage grazing trials with beef-store cattle and in-calf dairy heifers during four successive winters in Aberdeenshire are described. Many of the animals received only very small quantities of supplementary fodders, but their performance was satisfactory in all cases. During the last two winters, silage and oat straw contributed 40–50% of total food dry-matter intake. It is suggested that this level of supplementary feeding would be satisfactory in practice.
In a comparison of store-feeding systems, four in-wintered (housed) steers were 110 1b. per head heavier than their out-wintered monozygous twins at the end of the winter-feeding period. Live-weight differences averaged 27 1b. per head one month later and were negligible at the end of summer. From the results of a metabolism trial it was concluded that the spring weight-loss suffered by the housed cattle was due mainly to a reduction in the weight of gut contents.     

THE INTAKE AND NUTRITIVE VALUE OF FRESH, FROZEN AND DRIED SORGHUM ALMUM, DIGITARIA DECUMBENS AND PANICUM MAXIMUM

Sorghum almum, Digitaria decumbens and Panicum maximum were fed in fresh, frozen (−20 C) or dried (85° C) form to 21 wethers in metabolism cages. Neither freezing nor drying had a significant (P>0·05) effect on voluntary intake, dry-matter digestibility or organic-matter digestibility. Drying depressed the apparent digestibility of the nitrogen in all grasses but only in the case of D. decumbens was this significant (P<0·05). Freezing also depressed the apparent digestibility of N while both freezing and drying reduced N retention, compared with the fresh feed. None of these differences was significant.
Freezing and drying are thus methods of pasture preservation that can be used to study the intake and dry-matter digestibility of tropical pastures, but both methods may introduce bias into the measurement of N digestibility and retention.     

THE PRODUCTION OF EARLY SPRING GRASS

Spring nitrogen significantly increased the yields of early spring grass. The response per lb. of nitrogen applied in the early spring ranged from 9 to 28 lb. of dry matter, depending upon the weather. Autumn nitrogen significantly increased herbage yields during the autumn. The increase per lb. of nitrogen ranged from 12 to 22 lb. of dry matter.
Autumn nitrogen caused significant increases in the yield of early spring grass in 1956, but these increases were very small and not of practical importance.
The effects of autumn grazing on spring yields were not consistent and were small when compared with the effects of spring nitrogen. Both autumn grazing and autumn nitrogen tended to reduce the percentage of soluble carbohydrates in the stubble and roots of grasses in November.