The effect of introducing timothy, cocksfoot and red fescue into a perennial ryegrass sward and the application of sodium fertilizer on the behaviour of male and female cattle

Abstract

The effects on cattle grazing behaviour of introducing the three novel species into a perennial ryegrass pasture were examined in a Latin Square design. Castrated male and entire female cattle of similar age were grazed on plots of perennial ryegrass only (treatment 1), perennial ryegrass and timothy (treatment 2), perennial ryegrass, timothy and cocksfoot (treatment 3) and perennial ryegrass, timothy, cocksfoot and red fescue (treatment 4). Perennial ryegrass had the greatest nutritional value, with a high crude protein and low MADF content, whereas cocksfoot and red fescue had high MADF contents. The introduction of timothy had no effects on grazing behaviour. When cocksfoot was additionally included, the cattle grazed for longest on the cocksfoot plots and total grazing time and the time spent ruminating both increased. When red fescue was additionally included with the other three species it was mostly avoided. When they did graze the red fescue, the cattle had slow biting and walking rates and reduced lateral head movement, suggesting greater selectivity. Mean treatment herbage height was increased in treatments three and four because cocksfoot and red fescue were taller than the other two species. Sodium fertilizer increased the sodium concentration of all species but particularly perennial ryegrass and cocksfoot. The grazing time was only increased by sodium for these two species, and the rates of biting and walking during grazing were also increased, suggesting that sodium reduced selectivity. Male cattle had faster biting and walking rates than female cattle and extended lateral head movement during grazing. It is concluded that perennial ryegrass, timothy and cocksfoot were more acceptable to cattle than red fescue. There was an increase in acceptability of the natrophilic species, perennial ryegrass and cocksfoot, when sodium fertilizer was applied, suggesting that sodium content partly determines herbage acceptability.