Grazing Behaviour and Weight Changes in Calves Turned Out to Pasture

Abstract

Two studies are described in which the behaviour of 24 seven-month-old Friesian steer calves was observed. The first study (Gl) was undertaken at the time of turnout to pasture, and the second (G2) 5 days later. The calves appeared to adapt rapidly to the change in environment, though in study Gl grazing was frequently interrupted. In study G2 the calves showed normal behaviour patterns and spent a total of 4 25 hours grazing.There was a positive correlation between age and weight at turnout and time spent grazing in study Gl. However, this relationship was not apparent in G2, and there was no relationship between time spent grazing in Gl and G2.Mean weight loss upon turnout was 7 44% of liveweight, in spite of the feeding of hay and barley at grass. There was no relationship between weight at turnout and subsequent weight loss.The results confirmed other experimental findings which suggest that weight loss at turnout is largely a reflection of changes in the weight of alimentary tract contents, rather than an inability to adapt to the change in environment.The calves were grazed at two intensities ('low' and 'standard') during the grazing season. Growth rate in winter and weight at turnout were negatively correlated with growth rate in the first month of the grazing season. This relationship was more apparent in the 'low' intensity group which received a liberal daily herbage allowance at this stage of the season. Partial correlation analysis, in which pre-grazing growth rate was held constant, indicated that weight and age had little independent influence on growth rate at grass, though there was a positive relationship between weight for age at turnout and gain during the grazing season.The importance of a target weight at turnout is discussed in relation to the 18-month beef production system. It is concluded that younger, lighter, cattle at turnout may not be at a disadvantage when adequate amounts of herbage are on offer early in the grazing season.

The effect of age at which spring-born calves are introduced to pasture

“…This lower growth prior to turning out in 1977 seems to have led to some compensatory growth at grass since the overall gains from birth to housing were 0-63 kg/day and 0-62 kg/day for 1976 and 1977 respectively. Wilkinson & Cumberland (1970) examined the relationship between growth rate in the pre-grazing period and performance during the first month at grass and the data indicated that cattle tend to compensate for slower growth prior to turning out. A similar fact was reported by Baker & Baker (1965) and by Forbes, Raven & Robinson (1966).…”