Nutritive value of white clover and perennial ryegrass

Abstract

Thirty Romney wether hoggets were individually fed for 94 days at maintenance or ad lib. levels of nutrition on pure or 50 : 50 mixed diets of white clover and perennial ryegrass. Comparative slaughter and balance techniques were used to study the utilisation of dietary energy.The white clover contained higher levels of crude protein than the ryegrass, but lower levels of soluble and structural carbohydrates.Animals fed white clover grew faster than those fed ryegrass, but the growth rates of those on the mixed diet were not significantly different from the average of those on the two pure diets.The average a!)parent digestibility of the gross energy of all rations was 75%. Of the digestible energy (DE) 82% and 84% was metabolised by the maintenance and ad lib. animals, respectively. There were no significant differences between diets either in percentage digestibility or percentage metabolisability, but the metabolisable energy (ME) content of the dry matter (DM) consun;ed at the maintenance level (11.1 kJ/g) was significantly lower than for ad lib. feeding (11.4 kJ /g).Estimated fasting heat production and maintenance requirements averaged 319 and 511 kJ /kg W o . 7fi , respectively, where W is the ingesta-free body weight.For the white clover, mixed, and ryegrass diets efficiencies of utilisation of ME for maintenance were 67, 63, and 62%, and for gain 51, 40, and 33% respectively; net energy contents of the diets for maintem:nce (NEm) were 7.6, 6.7, and 6.7 kJ/g DM and for gain (NE") were 5.9,4.8, and 4.0 kJ /g DM. respectively. 401

The efficiency of energy utilization in growing cattle consuming fresh perennial ryegrass (Lolium perenne cv. Melle) or white clover (Trifolium repens cv. Blanca)

“…The results of the experiment are in agreement with those of Rattray &Joyce (1974) and confirm that C is potentially superior to G in terms of energy retention per unit MEI, but only at levels of feeding in excess of 1.65 Em/d in this experiment. The theoretical potential, in terms of RE, would appear greater for C than for G, suggesting that nutrient availability was likely to limit first retention on diet G.…”

“…voluntary intake (Ulyatt et al 1977), to an enhanced supply of absorbed protein (MacRae & Ulyatt, 1974;Ulyatt et al 1980;Beever et al 1985) and to an enhanced utilization of metabolizable energy (ME) for growth and fattening (Joyce & Newth, 1967;Rattray & Joyce, 1974).…”

Comparative energy and protein utilization in kids and lambs

“…These estimates of ME m were similar to or higher than the range of values obtained from indoor trials using the same technique for growing Iambs offered a range of diets but are lower than other reported values (Joyce et al 1972, Mitchell & Jagusch 1972Fennessy et al 1972;Rattray et al 1973 a, b,c;Rattray & Joyce 1974;Alam et al 1983). The value of 0-37 for lambs agrees with the value predicted by the Agricultural Research Council (1980) of 0-37 for diets of this mctabolizability.…”

Population differences in Trifolium repens L. response to ultraviolet-B radiation: foliar chemistry and consequences for two lepidopteran herbivores

“…The lack of pronounced effects on insect performance in our studies could also be attributed to the overall excellent nutritional quality of the white clover diet, which exhibited relatively high nutrient concentrations and low fiber levels across all treatments, compared with levels for this species under field conditions (Rattray and Joyce 1974;Wanjaiya et al 1993). Whether significant UV-Binduced changes persist in the field, where compounds of relevance to nutrition are likely to occur at more limiting levels for herbivore growth remains to be investigated.…”