https://www.esf.edu/EFB/faculty/documents/Forkmanetal2007reviewoffeartestsinanimals_000.pdf

A critical review of fear tests used on cattle, pigs, sheep, poultry and horses

1. A cornerstone concept of ecological immunology is that immune function, interacting with various aspects of individual health state, plays a central role in the life-history trade-offs between conflicting demands of survival and reproduction. In order to develop this research, more knowledge about the applicability and usefulness of different health state assays is needed.

2. Eleven, mostly hemato-serological, health state indices are described and their suitability for sensing the condition of breeding Great Tits (Parus major L.) in terms of measurement precision, constancy in time, diurnal variation, and sex- and site-related differences, is examined.

3. Measurement errors for the plasma albumin content, residual body mass, heterophile/lymphocyte ratio and total plasma protein content were relatively small compared with the total variation, suggesting these indices to be most adequate for ecological research. Measurement precision was lowest for the heterophile count and ‘buffy coat’ layer height (relative amount of leucocytes in total blood volume). Buffy coat layer height correlated weakly (r=0·21) with total leucocyte count estimated from blood smears and therefore appeared inappropriate for estimation of the leucocyte number.

4. Body mass (residual in respect to size) and intensity of Haemoproteus blood parasite infection were the least variable state indices during the nestling period (for both, the correlation between the values measured on the 8th and 15th days of the nestling period=0·71). Haematocrit, heterophile count and albumin/globulin ratio showed no individual constancy across the nestling period, while other traits revealed moderate but statistically significant correlations between 8th- and 15th-day values.

5. Leucocyte (both lymphocyte and heterophile) counts were higher among females captured at night compared with those captured during the day.

6. Females had higher intensities of Haemoproteus infection, higher heterophile counts and higher heterophile/lymphocyte ratios than males. Contrary to published information, females had higher haematocrits than males.

7. Haematocrit values in both sexes, as well as total plasma protein and albumin concentrations in males, differed significantly between Great Tits breeding in urban habitat and rural woodlands, respectively.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2435.1998.00219.x

Haematological health state indices of reproducing Great Tits: methodology and sources of natural variation

Molecular genetic studies of personality began with two high impact papers in 1996 that showed provisional associations between the dopamine DRD4 exon III repeat region and Novelty Seeking/Extraversion. These first two reports were shortly followed by an investigation linking Neuroticism/Harm Avoidance with the serotonin transporter (SLC6A4) promoter region polymorphism (5-HTTLPR). In the ensuing decade, thousands of subjects have been studied for association between these genes and personality, assessed by using self-report questionnaires, with erratic success in replication of the first findings for Novelty Seeking (DRD4) and Harm Avoidance (5-HTTLPR). Small effect sizes characteristic of non-Mendelian traits, polygenic patterns of inheritance and true heterogeneity between studies confound attempts to reach a consensus regarding the role of common polymorphisms in contributing to personality domains. Nevertheless, the current state of personality genetics is far from being bleak. Several new paradigms especially functional neuroimaging or 'imaging genomics' have strengthened the connection between 5-HTTLPR and anxiety-related personality traits. The demonstrations that early environmental information can considerably strengthen and even uncover associations between genes and behavior (Caspi's seminal studies and more recently the demonstration that early environment impacts on DRD4 and Novelty Seeking) are notable and herald a new era of personality genetics. Finally, consideration of the broader phenotypic expression of common polymorphisms (e.g. the 'social brain', altruism, etc.) and the use of new experimental paradigms including neurophysiological, neuropsychological and computer games that go beyond the narrow self-report questionnaire design will enable a deeper understanding of how common genetic polymorphisms modulate human behavior. Human personality, defined by Webster as the quality or state of being a person or the complex of characteristics that distinguishes an individual, surely requires a more encompassing view towards understanding its complex molecular genetic architecture.

The molecular genetic architecture of human personality: beyond self-report questionnaires

https://cyberleninka.org/article/n/1103450.pdf

A review of the human-horse relationship

Polymorphisms in several neurotransmitter-associated genes have been associated with variation in human personality traits. Among the more promising of such associations is that between the human dopamine receptor D4 gene (Drd4) variants and novelty-seeking behaviour. However, genetic epistasis, genotype– environment interactions and confounding environmental factors all act to obscure genotype–personality relationships. Such problems can be addressed by measuring personality under standardized conditions and by selection experiments, with both approaches only feasible with non-human animals. Looking for similar Drd4 genotype–personality associations in a free-living bird, the great tit (Parus major), we detected 73 polymorphisms (66 SNPs, 7 indels) in the P. major Drd4 orthologue. Two of the P. major Drd4 gene polymorphisms were investigated for evidence of association with novelty-seeking behaviour: a coding region synonymous single nucleotide polymorphism (SNP830) and a 15 bp indel (ID15) located 5 0 to the putative transcription initiation site. Frequencies of the three Drd4 SNP830 genotypes, but not the ID15 genotypes, differed significantly between two P. major lines selected over four generations for divergent levels of ‘early exploratory behaviour’ (EEB). Strong corroborating evidence for the significance of this finding comes from the analysis of free-living, unselected birds where we found a significant association between SNP830 genotypes and differing mean EEB levels. These findings suggest that an association between Drd4 gene polymorphisms and animal personality variation predates the divergence of the avian and mammalian lineages. Furthermore, this work heralds the possibility of following microevolutionary changes in frequencies of behaviourally relevant Drd4 polymorphisms within populations where natural selection acts differentially on different personality types.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2007.0337

Drd4 gene polymorphisms are associated with personality variation in a passerine bird.

Assessment of equine temperament by a questionnaire survey to caretakers and evaluation of its reliability by simultaneous behavior test

The variable number of tandem repeats (VNTR) polymorphism of the dopamine D4 receptor (DRD4) gene has been reported to be associated with the personality trait of novelty-seeking in humans. In the genus Equus, this region includes an 18-bp repeat unit and there are inter- and intraspecies differences in the number of repetitions. Because horses are unique among livestock species in that their temperament is considered important, we investigated the possible role of this region on equine temperament in thoroughbred horses. We simultaneously determined the sequences of this polymorphic region and administered a questionnaire survey to horse caretakers with questions about 20 different traits of their horses' temperament. Although there was no difference in the number of repeats among the 136 thoroughbred horses studied, two single nucleotide polymorphisms (SNPs), one of which might cause an amino acid change (A-G substitution), existed. By analyzing the association between these SNPs and temperament scores, a significant association was revealed between two temperament traits (Curiosity and Vigilance) and the A-G substitution. Horses without the A allele had significantly higher Curiosity and lower Vigilance scores than those with the A allele at the A-G substitution. In addition, similar associations between both temperament scores and each genotype of the A-G substitution were observed in two subgroups divided according to the time of their introduction to the farm. These results suggested that the SNP in the VNTR region of the equine DRD4 gene might be related to individual differences in equine temperament.

Association between equine temperament and polymorphisms in dopamine D4 receptor gene.

Assessment of equine temperament questionnaire by comparing factor structure between two separate surveys

This paper introduces an application of iris recognition technology, using the iris pattern for horse identification. There are several problems to be solved in horse iris recognition: (1) It is very difficult for horses to remain motionless, which leads to mislocation and loss of focus during image acquisition, so that the images often have poor quality. (2) Pupil size varies significantly between the conditions of dilation (mydriasis) and contraction (miosis). (3) Horse iris patterns are not clear. As a solution for issue (1), we used the reflection of the illumination sources employed for image acquisition and chose adequate images suitable for recognition. For issues (2) and (3), we propose region extraction appropriate to the equine eye structure, a stable coordinate model for pupil variation, and recognition using orthogonal wrinkles in the iris pattern. Recognition experiments based on 100 sets of horse iris data show that highly accurate horse identification is possible. © 2001 Scripta Technica, Syst Comp Jpn, 32(14): 12–23, 2001

Ryo Kusunose

Papers

Assessment of equine temperament by a questionnaire survey to caretakers and evaluation of its reliability by simultaneous behavior test

Association between equine temperament and polymorphisms in dopamine D4 receptor gene.

Assessment of equine temperament questionnaire by comparing factor structure between two separate surveys

A horse identification system using biometrics

A note on a behavioural indicator of satisfaction in stabled horses