Classification of low-resource livestock producers in the North West Province

(South African J of Animal Science, 2000, 30, Supplement 1: 109-110

The potential of legume pods as supplements to low quality roughages

(South African J of Animal Science, 2000, 30, Supplement 1: 107-108

Reproductive indices of Merino rams fed sun-cured Leucaena leucocephala forage

(South African J of Animal Science, 2000, 30, Supplement 1: 111-112

Feed evaluation

This manual has been produced to standardise some analytical procedures at ILCA and among those NARS scientists who may be interested in the aspects of feed evaluation which the manual attempts to address. The first part of the manual is on determination of voluntary intake, digestion and retention coefficients. It lists feed-intake measurement and collection of faeces and urine and presents procedures on preparing samples for chemical analysis. The second part examines special methods for measuring digestibility. This includes the indicator method, the nylon-bag technique, the nylon-bag procedure, handling nylon-bag data, and the Menke in vitro gas-production technique. The third part summarises the kinetics of digestion and of passage. Flow rates, rumen-evacuation technique, the use of markers to estimate passage rates, and continuous dosing with chromium-mordanted straw are discussed in this part. The fourth part is on the estimation of microbial protein supply using total urine excretion of purine derivatives. This includes sample preparation and mathematical procedure

Prediction of solid digesta passage rate using liquid passage rate as one of the input variables in ruminants

This study ascertained the influence of liquid passage rates on solid digesta passage rates and the possibilities of simultaneous prediction of solid and liquid passage rates in ruminants. Artificial neural networks were used to develop models of solid and solid-plus-liquid passage rates. Studies that reported fractional passage rates, class and body mass of ruminants were included in the dataset. Animal and feed factors that affect the rate of passage were identified. The database had observations of domestic and wild ruminants of variable body mass from 74 (solid using predicted liquid passage rate) and 31 (solid using observed liquid passage rate) studies. Observations were randomly divided into two data subsets: 75% for training and 25% for validation. Developed models accounted for 76% and 77% of the variation in prediction of solid passage rates using predicted and observed liquid passage rate as inputs, respectively. Simultaneous prediction accounted for 83% and 89% of the variation of solid and liquid passage rates, respectively. On validation using an independent dataset, these models attained 45% (solid using predicted liquid), 66% (solid using observed liquid), 50% (solid predicted with liquid) and 69% (liquid predicted with solid) of precision in predicting passage rates. Simultaneous prediction of solid and liquid passage rate yielded better predictions compared with independent predictions of solid passage rate. Simultaneous prediction of solid and liquid passage rates accounted for more variation compared with independent predictions of solid rates. Inclusion of liquid passage rate as an input variable gave better predictions of solid passage rates.Keywords: Fractional passage rate, prediction model, simultaneous prediction

Ruminal degradability and intestinal digestion of eight plant protein supplements used in ruminant diets

(South African J of Animal Science, 2000, 30, Supplement 1: 51-52

The reproductive performance of South African indigenous goats grazing Leucaena leucocephala pasture and natural veld during gestation

(South African J of Animal Science: 2000, 30, Supplement 1: 4-6