Animal production evaluation of herbage varieties. 1. Comparison of Aurora with Frances, Talbot and Melle perennial ryegrasses when grown alone and with clover

Abstract

Comparative herbage characteristics and sheep production (ewes and lambs until weaning and lambs thereafter) from swards of Aurora (very early flowering), Frances (early flowering), Talbot (intermediate flowering) and Melle (late flowering) varieties of perennial ryegrass {LoUum perenne) were studied under a continuous variable stocking management based on sward surface height guidelines. The varieties were assessed as grass-only (215 kg N ha""' fertilizer) and grass/clover (83 kg N ha"' fertilizer) pastures.Over 2 years (1985-86) total annual lamb production per hectare from grass-only swards of Aurora was 19% more than that from Frances despite similar herbage productivity. Differences between the varieties in lamb output were more pronounced as grass/clover swards, with Aurora producing 29 and X^'^n more Iamb than Melle and Talbot respectively and with Frances also giving 16% more than Melle. Overall lamb production from grass/clover swards was 10% more than that from the grassonly pastures, mainly due to 69% advantage in individual Iamb growth rates after weaning. Herbage organic matter digestibility, during the post-weaning period, was higher on grass/clover than on grass-only swards, and similarly with Aurora versus the other varieties. Under a frequent cut simulated grazing regime the relative herbage productivity of the four Correspondence: Mr J. M. M. Munro, IGER, Bronydd Mawr Research Centre, Trecastlc, Brecon, Powys, LD3 8RD, UK.varieties differed, with Aurora 13% less productive than Frances.The results are discussed in relation to the limitations of assessing performance under cutting, and the significance of the interaction in animal productivity between the two sward types.

Características Estruturais De Cultivares De Azevém Perene Como Critério De Seleção Para Maximizar O Consumo De Vacas Leiteiras Em Pastejo

“…A seleção feita pelo aumento da digestibilidade na amostragem de plantas em um determinado dia, ignorando-se o estádio de maturidade, pode conduzir a seleção a um retardamento na data de florescimento (Munro et al, 1992).…”

Cultivar Effects of Perennial Ryegrass on Herbage Intake by Grazing Dairy Cows

“…Early heading cultivars start their heading stage half May, but very early cultivars heading in the beginning of May have been reported (Munro et al 1992). Late heading cultivars start heading in June (Bonthuis et al 2004).…”

“…The cultivar effects on digestibility affect herbage intake and herbage utilization (Munro et al 1992). In vitro digestibility is considered by some breeders to be not important in perennial ryegrass (Boller et al 1994), because the level already is rather high (>75%), whereas others (Ingram and Beerepoot 1994) consider digestibility of great value.…”

“…In several studies in the last decade, the effect of perennial-ryegrass cultivars on herbage intake characteristics has been investigated (Munro et al 1992;Hazard et al 1998;Casey and Brereton 1999;Gowen et al 2003;Orr et al 2003;Barrett et al 2003;Orr et al 2005;Smit et al 2005b;Tas et al 2005). The intake of herbage by grazing herbivores could be divided into several characteristics that are important: daily intake, intake rate, bite mass, bite number or biting time and bite volume.…”

“…Studies with sheep (Munro et al 1992;Hazard et al 1998;Orr et al 2003) have shown that perennial-ryegrass cultivars can have effects on sheep. Munro et al (1992) showed a large effect of one cultivar (cv.…”