Further development and use of an automatic recording system in sheep grazing studies

Comparisons between some aspects of grazing and ruminating behaviour by sheep recorded automatically and by manual observation are reported.
Behaviour was recorded manually and automatically on four swards with surface heights of 3, 6, 9 and 12 cm. The automatic recording method gave significantly higher biting rates (78 v 67 ± 2·4 bites min^?1) than manual recording. Possible reasons for these differences are discussed. For recordings during ruminating there was no significant difference between the two recording methods.
As sward surface height increased biting rate decreased by 4·6 (± 0.65) and 2·9 (± 0·87) bites min^?1 cm^?1, and masticating rate increased by 4·5 (± 1·13) and 3·7 (± 0·95) chews min^?1 cm^?1 for the manual and automatic recording methods respectively.
It is concluded that the automatic recording system gives higher rates for jaw movements during grazing than manual recording but there is little difference between the two methods for activities recorded during ruminating.