Breed differences in behavioural response to challenging situations in kittens.

In a previous experiment, the behaviour of Oriental/Siamese/Abyssinian (OSA) kittens was compared with that of Norwegian Forest kittens (NFO) in a repeated Open Field Test (OFT), and significant differences emerged. To further investigate such variations, we analyzed kittens' responses to a potentially threatening object (TO) during the OFT. It was a metal spring enveloped in a cotton case suddenly bouncing out of the cylinder after the first 6 min of OFT exposure, and the test lasted 6 more minutes. From the 4th to the 10th week of age, during each test, the response of 43 OSA kittens and 39 NFO kittens to the TO was analyzed. Heart rate (HR) before and after the test was recorded. Behaviours were recorded and analyzed by focal animal sampling. Behavioural modifications recorded after TO exposure confirmed our suggestions on slow limbic system development in NFO kittens, as previously suggested by poor habituation and poor memory retention of repeated OFT exposure. The evident avoiding response to the TO confirmed the adoption in NFO kittens of an active-coping strategy towards challenge, as indicated also by their high scores for exploration and escape attempts. Otherwise, poor TO influence on exploration observed in OSA kittens suggested the adoption of a passive coping strategy, as previously shown by low levels of exploration and intra-session reduction in the number of vocalizations. Nevertheless, some of the behaviours observed, and the evidence of emotional tachycardia in OSA kittens, suggested also that the low level of activity recorded could have been due to a low arousability predisposition in this breed. The perception of a poorly arousing potential in the experimental setting might have influenced the perception of danger and the behaviour adopted in OSA kittens.

Association of dopamine- and serotonin-related genes with canine aggression.

Human-directed canine aggression was studied using 50 aggressive and 81 non-aggressive dogs. We examined 62 single nucleotide polymorphisms (SNPs) occurring in or in the close vicinity of 16 neurotransmitter-related genes. Allelic associations with aggression were identified for DRD1, HTR1D, HTR2C and SLC6A1. Risk or protective haplotypes for aggressive behaviour based on 2-5 SNPs were identified. The frequency of aggressive dogs varied significantly between the haplotypes within loci and the odds ratios of aggression in dogs with risk haplotypes compared with protective haplotypes varied from 4.4 (HTR2C) to 9.0 (SLC6A1). A risk haplotype across the neurotransmitter receptor gene HTR1D harboured a non-synonymous SNP with a potential effect on protein function. We identified no haplotypes in complete association with the recorded phenotypes, supporting a complex inheritance of aggression.

Breed differences in behavioural development in kittens.

Differences in behaviour of pure breed cats have been suggested but not wholly investigated. Oriental/Siamese/Abyssinian (OSA) kittens (n=43) were weekly compared with Norwegian Forest (NFO) kittens (n=39) from the 4th to the 10th week of age in a repeated Open Field Test (OFT) paradigm. Heart rate (HR) and rectal temperature (RT) before and after the test, and behavioural responses during the OFT were recorded. Behaviours registered were analysed by focal animal sampling. Significant breed differences were found; cats of the northern zones (NFO) seem to develop earlier thermoregulatory abilities. Precocious opening of eyes, higher locomotion scores and longer time spent standing, observed in OSA kittens may indicate an earlier neurological development. Inter breed differences recorded for exploration and locomotion seem to indicate coping style divergences: in the OFT challenging situation OSA kittens presented higher emotional tachycardia and performed more passively, with a faster decline in exploration and locomotion scores. NFO kittens exerted a more active behaviour as they spent more time exploring the arena and in escape attempts. Notwithstanding OSA and NFO cat selection was mainly aimed to improve divergent morphological traits, some different behavioural and physiological traits seem to have been maintained or co-selected within each breed.