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by ethological methods. The procedure still does not allow judgements to be made on the suffering of animals. However, we may reasonably assume that under conditions similar to those described above, the development of well- being for the animals is not guaranteed; for this we do not have to prove whether and how badly they suffer.

OBSERVATIONS OF LAMBS FEEDING ON TWO DIFFERENT TYPES OF FORAGE CROPS - RAPE AND STUBBLE TURNIPS

A.B. LAWRENCE and D.G.M. WOOD-GUSH

Edinburgh School of Agriculture, West Mains Road, Edinburgh (Gt. Britain)

ABSTRACT

Blackface and Suffolk growing lambs were observed for a period of 7 weeks in the two forage crops - rape and stubble turnips. Initially, qualita- tive notes were taken with the view to gaining a knowledge of sheep social behaviour. After 7 days, quantitative data were collected on the time that marked lambs (as focal animals) spent in various foraging, anti-predator and social behavioural postures. Data were also collected, by scan sampling, on the distance to nearest neighbour of the focal animal and the numbers of the two breeds of lambs within 5, 10, 15 and 20 yard radii from the focal animal.

The social behaviour of the lambs was found to match closely that described for wild and semi-wild sheep.

The two breeds showed no significant difference in their mean nearest neighbour distance, although such a difference has been recorded in adult Blackface and Suffolk sheep. Both breeds, however, showed a highly signifi- cant trend (P < 0.001) for focal animals to prefer a member of their own breed as their nearest neighbour. The Blackface, in addition, tended to have significantly more of their own breed (P < 0.005) at 15-20 yards from the focal animal than the Suffolks, indicating perhaps that they possessed the more dispersed group structure.

Qualitative and quantitative differences were recorded in the behaviour of the lambs in the two crops. After the first week, it was noted that whereas the lambs in the turnips had browsed over most, if not all, of the turnips, the lambs in the taller and denser rape crop had been unable, somehow, to make corresponding use of the crop. They had been reduced to eating the crop in a rather controlled fashion, where the line of eaten crop was advanced systematically each day in a “moving belt”, by lambs in tight groups feeding at the face of uneaten rape. These groups seldom ventured far, if at all, into the uneaten parts of the crop. It was also noted that the lambs in the rape appeared more nervous than those in the turnips.

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Quantitatively, the lambs in the rape, in the first 3 weeks when the rape stood higher and denser than the turnips, looked up more often in 15 min (P < 0.05) and showed an almost significant trend (P < 0.07) to be more tightly clumped than the lambs in the turnips.

These qualitative and quantitative results appear to indicate that the lambs in the rape were prevented from making full use of the taller, denser crop by an atavistic fear of predation. This effect appears to be mirrored in the live- weight gained by the lambs (e.g. the Suffolks put on more weight in the turnips, over the first 3 weeks, than they did in the rape (P < 0.005)).

It is, however, acknowledged that there were undoubtedly confounding nutritional and hormonal effects, in addition to the observed behavioural effects. It is therefore hard to say which, if any, of the above effects was the single most important factor in determining the liveweight gained.

THE EFFECTS OF TRANSPORTATION, THE PROXIMITY OF A BOAR AND OTHER STIMULI ON THE ATTAINMENT OF PUBERTY IN GILTS

W.H. CLOSE, D.B. STEPHENS, E.J.C. POLGE and I.B. START

A.R.C. Institute of Animal Physiology, Babraham, Cambridge and Animal Research Station, Huntingdon Road, Cambridge (Gt. Britain)

ABSTRACT

Early attainment of puberty in the gilt would appear to have both productive and economic advantages. Introduction of boars to groups of pre-pubertal gilts has been shown to advance the onset of puberty and synchronise oestrus in many instances. It has also been suggested that other stimuli, including transportation, may induce early puberty. The present ex- periments were designed to examine the effect of several management practices on the onset of puberty in gilts.

Treatments consisted of (a) exposure to real and simulated transport, (b) artificial boar odours via aerosol (“Boarmate”, Antec International, Sudbury), (c) exposure to mature breeding stock, and (d) periodic isolation. Eleven groups of animals, each consisting of 4 Large White gilts, were used. Initially, the animals were aged 141 rt 5 days and their mean body weight was 65 f 3 kg; at the end of the 9-12-week period of observation, the final mean body weight was 105 + 3 kg. Four series of observations were carried out.

Series I comprised 2 groups of animals accommodated in isolated pens. One group was left undisturbed (control), while individual animals from the experimental group were removed once weekly for a period of 1 h to an adjacent pen and held in a trolley, moved in a trolley to be near the