Abstract: The purpose of this paper is to give a short survey of the present problems concerning the genetic improvement of horse breeds. The evolution of these populations in Europe, characterized by a deep change from production of draught horses towards that of leisure horses, is described and the influence of the demographical parameters on the selection of these horse populations, is discussed. The generation interval represents an important handicap only surmounted in the case of racing breeds where a high selection intensity can be practised since all animals are subjected to performance testing. In the other cases, the farmer usually does not use modern breeding techniques, but uses crosses instead, which lead more easily to visible results. The available selection criteria are also dealt with. A distinction is made between direct estimates evaluating the abilities of the animals in practice and the indirect estimates measuring a character in correlation to previous ones. For the former estimates, a distinction is made between those resulting from competitions (handicap, records or earnings) and those resulting from direct in-station measurements (saddle, jumping, dressage abilities, draught power). For the indirect estimates, often used especially for the selection of mares, the most important analysis is obviously that of the conformation. However, in the future early selection criteria according to more physiological data should be sought and developed. Estimation of the breeding value according to a given ability is thereafter pointed out. There are two situations: “the panmictic case” concerning sport and draught horses and “the non-panmictic case” corresponding to racing horses, which give rise to some problems. The setting up of breeding plans is discussed. Due to the different economic situations and various objectives of horse production, conclusions are drawn about the role played by geneticists in the present development of this sector.

Abstract: Members of the genus Equus are large, nonruminant herbivores. These animals utilize the products of both enzymatic digestion in the small intestine and bacterial fermentation (volatile fatty acids) in the cecum and large colon as sources of metabolizable energy. Equine animals rely primarily upon oropharyngeal and external stimuli to control the size and duration of an isolated meal. Meal frequency, however, is regulated by stimuli generated by the presence and (or) absorption of nutrients (sugars, fatty acids, protein) in both the large and small intestine plus metabolic cues reflecting body energy stores. The control of feeding in this species reflects its evolutionary development in an environment which selected for consumption of small, frequent meals of a variety of forages.

Abstract: Social licking patterns of heifer and steer herds were observed and recorded during periods of resting and intermittent feeding. The results revealed the following features: (1) heifers and steers had 15.0 and 15.2 social licking interactions per hour which lasted for 37.8 and 41.0 s on average, respectively. The average time an animal spent licking was about 25 s per hour; (2) all the animals in the herds were licked by others, but only 72.3% of the animals licked other animals; (3) the animals close in the social hierarchy tended to lick each other for a longer time than did remote animals; (4) the time receiving l licking and weight gain tended to be positively correlated. The observations suggest that (1) the motivation of giving licking may be individual-specific and may be influenced by genetic factors, while that of receiving licking appears to be general, and that (2) social licking may mean not only cleaning the skin and hair of a passive partner, but also leading it to psychological stability.

Abstract: The feeding and drinking behavior of 11 mares and 15 foals living on pasture with free access to water was recorded during 2,340 15-min focal samples taken over 2 yr. Lactating mares on pasture spent about 70% of the day feeding. Foals began feeding on their first day of life. As they grew older, they spent progressively more time feeding, but still spent only 47 +/- 6% of the time feeding by 21 wk of age. Foals fed primarily during the early morning and evening. While grass formed the major proportion of the diet of both foals and mares, they also ate clay, humus, feces, bark, leaves and twigs. Almost all feeding by foals was done while their mothers were feeding. Movement to water sources was frequently, but not invariably, carried out by an entire herd. Frequency (P = .005) but not duration (P greater than .05) of drinking bouts by mares increased as the temperature increased. Frequency was greatest at 30 to 35 C, at which temperature mares drank once every 1.8 h. Frequency of drinking varied with the time of day (P less than .01), being rarest during the early morning (0500 to 0900 h eastern daylight time) and most frequent during the afternoon (1300 to 1700 h). Drinking by foals was very rare. The youngest age at which a foal was observed to drink was 3 wk, and 8 of 15 foals were never observed to drink before weaning.