Abstract: Like most large grazing herbivores, horses select their food based on visual cues, odour, taste, texture, availability and variety. There is relatively little published information about the role of flavour in diet selection by domestic horses in comparison with other domestic and companion animals. However, previous trials investigating effects of diet flavour in stabled horses indicated significant effects on foraging behaviour and selection. In this series of three trials we aimed to determine relative acceptance by presenting flavour preference tests to eight horses. Horses were stabled and fed hay ad lib on trial data collection days plus a standard unflavoured concentrate ration at 7:30 a.m. In Trial 1, 15 flavours were separately presented in standard 100 g cereal by-product meals and the trial was replicated. Quantity consumed, time of completion, partial rejection or refusal were recorded. Order of presentation was determined by a Latin Square design. Trial data were collected on five sampling days, separated by a minimum of 1 day. Horses were presented with six flavoured meals daily; minimum 1 h between the meals. Twelve flavours were universally accepted and of these the eight flavours with fastest mean consumption times (banana, carrot, cherry, cumin, fenugreek, oregano, peppermint and rosemary) were presented in paired preference tests in Trial 2. In Trial 2, all paired combinations of the eight flavours were presented, in two tests per day at noon and 4 p.m. Presentations of the same flavour were separated by at least 1 day. Paired presentations were in 300 g cereal by-product. Presentations were terminated when approximately half of the total amount presented had been consumed. Flavour preferences were expressed as a ratio from 0 (rejection) to 1 (exclusive consumption). Paired flavour preferences produced the following rank order: fenugreek, banana, cherry, rosemary, cumin, carrot, peppermint, oregano. In Trial 3, relative consumption times of mineral pellets flavoured with fenugreek and banana were significantly reduced in comparison with unflavoured pellets. In these short-term trials, flavour had significant effects on diet acceptance, selection and consumption times.

Abstract: Genetic parameters of eventing horse competitions were estimated. About 13 000 horses, 30 000 annual results during 17 years and 110 000 starts in eventing competitions during 8 years were recorded. The measures of performance were logarithmic transformations of annual earnings, annual earnings per start, and annual earnings per place, and underlying variables responsible for ranks in each competition. Heritabilities were low (0.11 / 0.17 for annual results, 0.07 for ranks). Genetic correlations between criteria were high (greater than 0.90) except between ranks and earnings per place (0.58) or per start (0.67). Genetic correlations between ages (from 5 to 10 years old) were also high (more than 0.85) and allow selection on early performances. The genetic correlation between the results in different levels of competition (high/international and low/amateur) was near 1. Genetic correlations of eventing with other disciplines, which included partial aptitude needed for eventing, were very low for steeplechase races (0.18) and moderate with sport: jumping (0.45), dressage (0.58). The results suggest that selection on jumping performance will lead to some positive correlated response for eventing performance, but much more response could be obtained if a specific breeding objective and selection criteria were developed for eventing.

Abstract: A selection scheme for jumping sport horses is modelled with four stages of selection for males and one stage for females. The selection objective included three traits: conformation and gaits (CG, weighted 20%), competition jumping (CJ, weighted 60%) and a third trait (TT, weighted 20%) such as sperm quality or orthopaedic status. The first selection stage is based on knowledge of the pedigree with the aim of selecting horses suitable for CG test (at 3 years old) and CJ test (at 5 years old). The second stage includes the horse's own performance with respect to CG and CJ with the aim of selecting horses suitable for the TT test. The third stage is the selection of a limited number of males who are allowed to reproduce. The fourth stage (at 12 years old) takes into account the results of the horse's progeny. Females are selected in one step, whatever the number of performances measured at 5 years old. The annual genetic response was 9.4% genetic standard deviation of the objective, 2.6% for CG, 9.0% for CJ and 1.5% for TT. Results showed that selection by progeny testing did not contribute much to genetic response (12% of progeny issued from proven sires), the female pathway represented 26% of genetic response, TT was difficult to improve when the genetic correlation was unfavourable (- 0.6% genetic standard deviation for - 0.20 genetic correlation), and should consequently be directed towards the use of molecular markers. When compared with a selection scheme involving a station test, genetic response was the same if the breeding values used for selection before entering the station test took into account the results of the relatives for CJ and CG. This revealed the importance of an extensive performance test (like for competition performance) when designing breeding schemes for sport horses.

Abstract: In recent years evidence has been accumulating that personalities are not only found in humans but also in a wide range of other animal species. Individuals differ consistently in their behavioural tendencies and the behaviour in one context is correlated with the behaviour in multiple other contexts. From an adaptive perspective, the evolution of animal personalities is still a mystery, because a more flexible structure of behaviour should provide a selective advantage. Accordingly, many researchers view personalities as resulting from constraints imposed by the architecture of behaviour (but see ref. 12). In contrast, we show here that animal personalities can be given an adaptive explanation. Our argument is based on the insight that the trade-off between current and future reproduction often results in polymorphic populations in which some individuals put more emphasis on future fitness returns than others. Life-history theory predicts that such differences in fitness expectations should result in systematic differences in risk-taking behaviour. Individuals with high future expectations (who have much to lose) should be more risk-averse than individuals with low expectations. This applies to all kinds of risky situations, so individuals should consistently differ in their behaviour. By means of an evolutionary model we demonstrate that this basic principle results in the evolution of animal personalities. It simultaneously explains the coexistence of behavioural types, the consistency of behaviour through time and the structure of behavioural correlations across contexts. Moreover, it explains the common finding that explorative behaviour and risk-related traits like boldness and aggressiveness are common characteristics of animal personalities.

Abstract: PENN, D. AND W. K. POTTS. Untrained mice distinguish MHC-determined odors. PHYSIOL BEHAV 64(3) 235-243, 1998.--Immune recognition occurs when foreign antigens are presented to T-lymphocytes by molecules encoded by the highly polymorphic genes of the major histocompatibility complex (MHC). House mice (Mus musculus) prefer to mate with individuals that have dissimilar MHC genes. Numerous studies indicate that mice recognize MHC identity through chemosensory cues; however, it is unclear whether odor is determined by classical, antigen-presenting MHC loci or closely linked genes. Previous studies have relied on training laboratory mice and rats to distinguish MHC-associated odors, but there are several reasons why training experiments may be inappropriate assays for testing if MHC genes affect odor. The aim of this study was to determine whether classical MHC genes affect individual odors and whether wild-derived mice can detect MHC-associated odors without training. In the first experiment, we found that wild-derived mice can be trained in a Y-maze to detect the odors of mice that differ genetically only in the MHC region. In the second and third experiments, we used a naturalistic habituation assay and found that wild-derived mice can, without training, distinguish the odors of mice that differ genetically only at one classical MHC locus (dm2 mutants).