Methods to determine forage intake by lambs on Italian ryegrass

ABSTRACT. This study was conducted to evaluate the use of chromium oxide and the content of fecal nitrogen to estimate forage intake by female lambs on Italian ryegrass pasture. The pasture was managed under different forage allowances (FA): 6, 9 and 12% BW. The experiment was a randomized split-split plot design, in which the forage allowances were considered as main plots, the phenological stages as subplots and methods to determine intake as sub-subplots. Forage intake, in the ryegrass vegetative stage, is independent of forage allowance. Lower allowances limit forage intake from the pre-flowering stage, while at the reproductive stage, intake was lower in FA6, intermediate in FA9 and higher in FA12. The estimation of organic matter intake by lambs on Italian ryegrass is similar when chromium oxide and fecal nitrogen are used as markers. The forage intake according to forage allowances depends on the sward structure and is limited by high stem mass at the end of the phenological cycle. Keywords: Lolium multiflorum Lam., fecal nitrogen, lambs, chromium oxide, intermittent grazing. Métodos para determinação do consumo de forragem por cordeiras em pastagem de azevém RESUMO. Este experimento foi realizado para mensurar a ingestão de forragem por cordeiras, em pastagem de azevém, utilizando o óxido de cromo e o teor de nitrogênio fecal. A pastagem foi manejada sob distintas ofertas de forragem (OF): 6, 9 e 12% do PC. O delineamento experimental foi inteiramente casualizado, com estrutura de parcelas sub subdivididas, sendo as ofertas de forragem as parcelas principais, os estádios fenológicos, as subparcelas e os métodos de determinação da ingestão as sub sub-parcelas. A ingestão nos estádios vegetativo do azevém independe da oferta de forragem. As menores ofertas limitam a ingestão de forragem a partir do pré-florescimento enquanto no estádio reprodutivo do azevém a ingestão é menor na OF6, intermediária na OF9 e maior OF12. A estimativa da ingestão de matéria orgânica por cordeiras em pastagem de azevém é similar quando são utilizados o óxido de cromo e o nitrogênio fecal como marcadores. A ingestão de forragem em função das ofertas de forragem é dependente da estrutura do dossel e é limitada no final do ciclo do pasto em função da elevada massa de colmos. Palavras-chave: Lolium multiflorum Lam., nitrogênio fecal, ovinos, óxido de cromo, pastejo intermitente

Patterns of use of time by heifers with or without supplementation at different phenological stages of winter grasses

A joint data analysis was performed to characterize forage intake rate and patterns of use of time by grazing heifers in cold season pastures. Heifers received or not energetic supplementation at different phenological stages of grasses (vegetative, pre-flowering and flowering). Experiments involved 360 heifers with initial age of eight months and average body weight of 145 ± 17 kg, on continuous grazing method and variable number of animals.  Supplementaed heifers consumed 17.0% less forage and 22.2% less leaf blades than heifers exclusively on pasture. Grazing activity was concentrated in the afternoon shift, regardless of the feeding system and phenological stages evaluated, with the longest event of rumination during the night. Forage intake rate is similar, regardless of supplement intake and phenological stages of grasses.

Methods to determine forage intake by lambs on Italian ryegrass

ABSTRACT. This study was conducted to evaluate the use of chromium oxide and the content of fecal nitrogen to estimate forage intake by female lambs on Italian ryegrass pasture. The pasture was managed under different forage allowances (FA): 6, 9 and 12% BW. The experiment was a randomized split-split plot design, in which the forage allowances were considered as main plots, the phenological stages as subplots and methods to determine intake as sub-subplots. Forage intake, in the ryegrass vegetative stage, is independent of forage allowance. Lower allowances limit forage intake from the pre-flowering stage, while at the reproductive stage, intake was lower in FA6, intermediate in FA9 and higher in FA12. The estimation of organic matter intake by lambs on Italian ryegrass is similar when chromium oxide and fecal nitrogen are used as markers. The forage intake according to forage allowances depends on the sward structure and is limited by high stem mass at the end of the phenological cycle