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Biomedical subjects

G Trillat

Publications and source records attributed to G Trillat.

3 recordsLinked to original sources

Individual differences in docility in Limousin cattle.

Docility tests were performed over 3 yr on 906 Limousin heifers sired by 34 males. The heifers were tested individually when they were 10 to 11 mo old in a pen with a handler who had 2 min to lead the animal to a corner, keep it there for 30 consecutive seconds, and then to stroke it. Behaviours of the animals were recorded and scores calculated. The first score (docility score) was a continuous variable combining the greatest possible information. The second score (docility criterion) was a categorical trait with four classes. Tests were performed by seven different handlers. The effects of handler, year, birth period, dam parity, birth region, husbandry system, and sire were estimated. Handlers, birth period, husbandry system, and sire had significant effects. In particular, animals that were managed indoors were more docile than those reared out-of-doors at least part of the time. Heritability estimates of the docility score (.22) and docility criterion (.18) seem sufficient to select for docility traits.

Aggression↗

Importance of the characteristics of the young in the manifestation and establishment of maternal behaviour in sheep.

The role played by the lamb in the regulation of maternal behaviour of the ewe around parturition was investigated in three experiments. In the first, the spontaneous manifestation of that behaviour was observed in parturient ewes when their lambs were swapped with either newborn or 12 to 24-hr old alien lambs. The ewes were undisturbed, or only slightly so, when their lambs were exchanged for alien newborn. In contrast, very obvious and significant differences were observed when swapping involved 12 to 24-hr old lambs. In the second experiment, ewes totally separated from their lambs at birth and for 12 hrs accepted a newborn alien lamb more readily than their own 12-hr old lamb at the time of reunion. In the third experiment, ewes were maintained in partial contact with their lambs for 12 hrs and maternal behaviour was tested at that time. The ewes remained maternal up to the time of testing only if they could smell their lambs. It was concluded that some characteristics of the newborn lamb are necessary for the development of adequate maternal behaviour.

Animals↗

Colostrum immunoglobulin concentration in cows: relationship with their calf mortality and with the colostrum quality of their female offspring.

Samples of colostrum were taken from 180 suckling cows (beef cows) from the same herd, during the 3 hours immediately after calving over a period of 4 consecutive years. Total proteins in colostrum-whey were estimated by the biuret method, and concentrations of gamma-globulins determined by electrophoresis. The significance of the close relationship between calf mortality and gamma-globulin levels in the maternal colostrum was studied. An attempt was made to define levels suitable for the health of the calves. Twin birth, age at calving and food intake towards the end of the gestation period, whatever their effect on calf mortality rate, did not bring about any significant variation in the levels of colostral gamma-globulins. On the other hand, however, cows suffering from various infections had lower levels of colostral gamma-globulins, and produced a higher calf mortality rate. A high degree of repeatability in gamma-globulin levels was observed in colostrums produced by the same cow during successive calvings. A correlation between colostral gamma-globulin levels of a particular cow and those of her female offspring was also found. This result, which should be controlled on a larger number of animals, suggests the possibility of an approach of the problem of calf mortality, using a sanitary and genetic selection designed to reduce the number of cows producing colostrum with low levels of gamma-globulins.

Animals↗