Prediction of intake by cattle from degradation characteristics of roughages

Abstract

Five different straws consisting of two varieties of winter barley, two varieties of spring barley and one variety of winter wheat were chosen due to differences in degradation characteristics determined by using nylon bags incubated in the rumen of cattle and describing the straw using the equation: p = a + b (1 – e–ct). To increase variation in degradability, batches of the same straws were also treated with anhydrous ammonia in a sealed oven.The straws were subsequently offered ad libitum to groups of steers given a daily supplement of 1·5 kg concentrate and untreated straws were supplemented with urea. The dry-matter intake (DMI) of the straws varied from 3·4 to 5·7 kg/day, the digestible DMI from 1·4 to 3·5 kg/day and growth rate from 106 to 608 g/day.By using multiple regression of a, b, c from the exponential equations characterizing degradability of the straw, the correlation coefficients with DMI, digestible DMI and growth rate were 0·88, 0·96 and 0·95 respectively.

Determining Nutritive Value of Cereal Crop Residues and Lentil (<i>Lens esculanta</i>) Straw for Ruminants

“…Since the cell-wall carbohydrates are the most important components of the straws, an efficient microbial digestion in the rumen is crucial for their utilization in ruminant feeding. In recent years, a number of studies have suggested that degradation characteristics of these types of feeds in the rumen will provide a useful basis for the evaluation of their nutritive value [13] …”

On the suitability of Illius and Gordon\'s model for simulating the intake and digestibility of roughage diets by ruminants

“…These models are state-specific and thus only valid under similar circumstances under which they have been developed. Some of these models rely entirely on animal characteristics (ARC, 1980) while others are based on feed properties such as degradability (Ørskov et al, 1988;Blumel & Ørskov, 1993;Kibon & Ørskov, 1993) or on urinary excretion products (Nsahlai et al, 2002). Since the relationship between roughage intake and degradability is a positive one, this only strengthens the view that roughage intake by ruminant animals is limited by rumen (gut) "fill".…”

Predição do Consumo Voluntário do Capim-Tanzânia (Panicum maximum, J. cv. tanzânia), sob Pastejo, por Vacas em Lactação, a partir das Características de Degradação

“…Sabe-se ainda que outras características da forragem possam ter influenciado a predição da ingestão, como a taxa de redução de partículas maiores, o tempo de colonização destas, assim como a taxa constante de saída de digesta ruminal (∅RSKOV et al, 1988) e que não estão presentes como variáveis nestas equações.…”