Sheep numbers required for dry matter digestibility evaluations when fed fresh perennial ryegrass or forage rape

Abstract

Research trials with fresh forages often require accurate and precise measurement of digestibility and variation in digestion between individuals, and the duration of measurement periods needs to be established to ensure reliable data are obtained. The variation is likely to be greater when freshly harvested feeds are given, such as perennial ryegrass (Lolium perenne L.) and forage rape (Brassica napus L.), because the nutrient composition changes over time and in response to weather conditions. Daily feed intake and faeces output data from a digestibility trial with these forages were used to calculate the effects of differing lengths of the measurement period and differing numbers of sheep, on the precision of digestibility, with a view towards development of a protocol. Sixteen lambs aged 8 months and weighing 33 kg at the commencement of the trial were fed either perennial ryegrass or forage rape (8/treatment group) over 2 periods with 35 d between measurements. They had been acclimatised to the diets, having grazed them for 42 d prior to 11 days of indoor measurements. The sheep numbers required for a digestibility trial with different combinations of acclimatisation and measurement period lengths were subsequently calculated for 3 levels of imposed precision upon the estimate of mean dry matter (DM) digestibility. It is recommended that if the standard error of the mean for digestibility is equal to or higher than 5 g/kg DM, and if sheep are already used to a fresh perennial ryegrass or forage rape diet, then a minimum of 6 animals are needed and 4 acclimatisation days being fed individually in metabolic crates followed by 7 days of measurement.

Pelleting of a Total Mixed Ration Affects Growth Performance of Fattening Lambs

“…Total faeces collection was used to determine the apparent total tract digestibility of nutrients ( 28 ). One day before the start of the total collection, the lambs were fitted with the collection harnesses to allow adaptation to the equipment.…”

Dietary Supplementation of Yeast Culture Into Pelleted Total Mixed Rations Improves the Growth Performance of Fattening Lambs

“…Lambs were given 6 days for adaption and 6 days for sample collection. Feed offered and refused, and the outputs of faeces and urine were collected and quantified daily using the total faeces collection technique ( 29 ). One-fifth of faeces was subsampled each day with half acidified for CP analysis only and another half not acidified for the analysis of other nutrients.…”

Effects of forage rape at various levels on growth performance, carcass traits, meat quality, rumen fermentation and rumen microbiota of Hu lambs

“…Forage rape (Brassica napus) is an oil crop grown worldwide. Apart from being used as an oil crop, forage rape has become part of the forage system for ruminants grazing on pasture in Europe, Australia and New Zealand [1]. In southern China, there is a longterm shortage of high-quality forage, which challenges the development of ruminant breeding.…”