Availability and issues of 3D-printed skull models for veterinary anatomy laboratories from students' perspective before and during the COVID-19 pandemic.

Three-dimensional (3D)-printed models of bones are a convenient and durable alternative to real bone specimens, and they have been used in anatomy laboratories. It is necessary to identify the precise advantages of 3D-printed models from all perspectives; not only the improvement in students' knowledge of anatomy but also the students' assessment of such models. Here, students of veterinary medicine and animal science evaluated the reproducibility and effectiveness of 3D-printed models as a learning tool by completing our questionnaires, with a focus on their understanding of the skull-morphological differences among dog breeds. With the COVID-19 pandemic having obliged veterinary universities to provide courses online, we also investigated how the pandemic affected the students' evaluation of the 3D-printed models. The questionnaire results revealed that the animal science students were satisfied with the reproducibility of the 3D-printed models, but the veterinary students were not (they preferred to use real specimens). The skull differences were well understood by both types of students, indicating that 3D-printed models are effective for learning about rare skeletal specimens. The veterinary students who experienced the COVID-19 pandemic tended to choose real specimens more often than those who did not have this experience. Our results suggest that the use of 3D-printed models as an introduction and the use of real specimens in anatomy laboratory courses can be adequate for veterinary students. Together our findings suggest ways to improve the educational performance of 3D-printed models for veterinary students who need to understand the anatomy of many species.

Epigenomic features associated with body temperature stabilize tissues during cold exposure in cold-resistant pigs.

Cold stress in low-temperature environments can trigger changes in gene expression, but epigenomics regulation of temperature stability in vital tissues, including the fat and diencephalon, is still unclear. Here, we explore the cold-induced changes in epigenomic features in the diencephalon and fat tissues of two cold-resistant Chinese pig breeds, Min and Enshi black (ES) pigs, utilizing H3K27ac CUT&Tag, RNA-seq, and selective signature analysis. Our results show significant alterations in H3K27ac modifications in the diencephalon of Min pigs and the fat of ES pigs after cold exposure. Dramatic changes in H3K27ac modifications in the diencephalon of Min pig are primarily associated with genes involved in energy metabolism and hormone regulation, whereas those in the fat of ES pig are primarily associated with immunity-related genes. Moreover, transcription factors PRDM1 and HSF1, which show evidence of selection, are enriched in genomic regions presenting cold-responsive alterations in H3K27ac modification in the Min pig diencephalon and ES pig fat, respectively. Our results indicate the diversity of epigenomic response mechanisms to cold exposure between Min and ES pigs, providing unique epigenetic resources for studies of low-temperature adaptation in large mammals.

Breed Differences in Serum Testosterone Levels of Male Pigs Are Highly Correlated with Differences in Testicular mRNA Levels of Enzymes and Proteins Involved in Testosterone Biosynthesis Process.

To clarify the causes of breed differences in serum testosterone levels of male pigs, which affect the mRNA expression of drug metabolizing enzymes and drug transporters in the liver and kidney, we focused on testicular enzymes and proteins involved in testosterone biosynthesis process and comparatively examined their mRNA levels by real time RT-PCR among low serum testosterone-type Landrace pigs and high serum testosterone-type Meishan and Landrace/Meishan-crossbreed (LM and ML) pigs. Testicular mRNA levels of the enzymes (3-hydroxy-3-methylglutaryl-CoA synthase 1 and 3-hydroxy-3-methylglutaryl-CoA reductase) and proteins (low density lipoprotein receptor and scavenger receptor class B member 1) affecting intracellular levels of cholesterol, a precursor of testosterone, were 2-5-fold higher in Meishan, LM and ML pigs than in Landrace pigs. Likewise, the mRNA levels of steroidogenic acute regulatory protein, which imports cholesterol to the inner mitochondrial membrane, and of testosterone biosynthesis enzymes (CYP11A1 and CYP17A1) were over 10-fold and approximately 3-fold higher, respectively, in Meishan, LM and ML pigs than in Landrace pigs. Furthermore, positive correlations between those mRNA levels and serum testosterone levels were observed. Despite large breed differences in testicular mRNA levels described above, no significant breed differences in intratesticular testosterone levels were observed. The present findings strongly suggest that breed differences in serum testosterone levels of male pigs are probably, at least in part, caused by differences in testicular mRNA levels of enzymes and proteins involved in testosterone biosynthesis process and by differences in the levels of testosterone released from testes.

Effect of lameness on feeding behavior of zero grazed Jersey dairy cows.

The dairy industry faces major challenges with high levels of lameness, in parallel to an increased consumer focus on animal welfare. This encourages farmers to consider more robust breeds, such as Jersey cows. As little is known about the behavior of this breed under loose housing conditions, the present study sought to describe the feeding behavior of lame and non-lame Jersey cows in different parities. Such breed-specific information of behavioral changes is needed for breed-specific herd management decisions and may contribute to identifying animals that are susceptible to developing lameness in the future, thus reducing impacts on the welfare and production of cows. Feeding data from 116 Danish Jersey cows were collected using automatic feeders, and lameness status was assessed by technicians every second week. The cows were kept in a loose housing system, with cubicles, a slatted concrete floor, and automatic milking robots. Eating time per visit and per day, the number of visits per day, and intervals between meals were analyzed using generalized linear mixed effects models. The effect of lameness was not significant for any variable. Primiparous Jersey cows had significantly longer eating times per day, shorter meal intervals, and a lower number of visits per day than older Jersey cows. Week in lactation affected the eating time per visit and per day, the number of visits, and between-meal intervals. In conclusion, we found no differences between lame and non-lame Jersey cows but between parities, which disagree with previous research on other breeds, suggesting that Jersey cows not just differ in size and looks but also in their behavioral reaction when lame. Although data from only one herd of a research center were used, this study has demonstrated the need for further research about breed-specific differences and their implications for the health and welfare of the animals.

Effects of High Heat Load Conditions on Blood Constituent Concentrations in Dorper, Katahdin, and St. Croix Sheep from Different Regions of the USA.

Forty-six Dorper (DOR), 46 Katahdin (KAT), and 43 St. Croix (STC) female sheep (initial body weight of 58, 59, and 46 kg, respectively, SEM = 1.75; 3.3 ± 0.18 years of age, 2.6−3.7), derived from 45 commercial farms in four regions of the USA (Midwest, Northwest, Southeast, and central Texas), were used to evaluate responses in blood constituent concentrations to increasing heat load index (HLI) conditions. There were four sequential 2 weeks periods with target HLI during day/nighttime of 70/70 (thermoneutral zone conditions), 85/70, 90/77, and 95/81 in period 1, 2, 3 and 4, respectively. A 50% concentrate pelletized diet was fed at 53.3 g dry matter/kg body weight0.75. The analysis of most constituents was for samples collected on the last day of the second week of each period at 13:00 h; samples for cortisol, thyroxine, and heat shock protein were collected in week 2 and 8. Previously, it was noted that resilience to high HLI conditions was greatest for STC, lowest for DOR, and intermediate for KAT. There were few effects of region. Other than hemoglobin concentration, there were no interactions between breed and period. Blood oxygen concentration was greatest (p < 0.05) among breeds for STC (5.07, 5.20, and 5.53 mmol/L for DOR, KAT, and STC, respectively; SEM = 0.114) and differed among periods (4.92, 5.26, 5.36, and 5.52 mmol/L for period 1, 2, 3, and 4, respectively; SEM = 0.093). There were breed differences (i.e., main effects; p < 0.05) in glucose (50.0, 52.6, and 52.1 mg/dL; SEM = 0.76), urea nitrogen (17.2, 17.3, and 19.4 mg/dL; SEM = 0.33), creatinine (0.991, 0.862, and 0.802 mg/dL; SEM = 0.0151), total protein (6.50, 6.68, and 6.95 g/l; SEM = 0.017), triglycerides (28.4, 29.1, and 23.5 mg/dL; SEM = 0.87), and cortisol (6.30, 8.79, and 6.22 ng/mL for DOR, KAT, and STC, respectively; SEM = 0.596). Differences among periods (p < 0.05) were observed for lactate (27.9, 25.3, 27.8, and 24.0 mg/dL; SEM = 0.99), creatinine (0.839, 0.913, 0.871, and 0.917 mg/dL; SEM = 0.0128), total protein (6.94, 6.66, 6.60, and 6.65 g/l; SEM = 0.094), and cholesterol (60.2, 56.5, 58.3, and 57.6 mg/dL for period 1, 2, 3, and 4, respectively; SEM = 1.26). In addition, the concentration of cortisol (7.62 and 6.59 ng/mL; SEM = 0.404), thyroxine (5.83 and 5.00 µg/dL; SEM = 0.140), and heat shock protein (136 and 146 ng/mL for week 2 and 8, respectively; SEM = 4.0) differed between weeks (p < 0.05). In conclusion, the lack of interaction between breed and period with different HLI conditions suggests that levels of these blood constituents were not highly related to resilience to high HLI.

Sex, Organ, and Breed Differences in the mRNA Expression of Drug Transporters in the Liver and Kidney of Pigs.

Domestic pigs are attractive as an animal model for humans because of their anatomical and physiological similarities to humans. In this study, sex, organ, and breed differences in the mRNA expression of drug transporters such as breast cancer resistance protein (BCRP), multidrug resistance protein 1 (MDR1), multidrug resistance associated protein 2 (MRP2), organic anion porting polypeptide 1B3 (OATP1B3), organic anion transporters (OAT1, OAT2, and OAT3), and organic cation transporters (OCT1 and OCT2) were examined by RT-PCR in the liver and kidney of 5-month-old Meishan and Landrace pigs. No sex differences in the amount of BCRP mRNA were observed in both breeds. In Meishan pigs, sex differences (male < female) in the mRNA amounts of MDR1, OATP1B3, and OCT1 were observed in the liver. Similarly, sex differences in the mRNA amounts of MRP2, OAT1, OAT2, OAT3, and OCT2 were observed in the kidney of Meishan pigs: male > female for MRP2, OAT3, and OCT2, and male < female for OAT1 and OAT2. However, no such sex differences were observed in Landrace pigs. In addition, regardless of breed, hepatic OAT1, OAT3, and OCT2 mRNAs and renal OATP1B3 mRNA were not detected. Thus, organ and breed differences in the expression of drug transporters suggest the existence of genetically controlled organ-selective factors. Furthermore, additional experiments in castrated and/or testosterone propionate-treated pigs strongly suggested that sex and breed differences in the gene expression of drug transporters, especially hepatic OCT1 and renal OAT1, were primarily due to the difference in serum testosterone concentration.

Comparison of the feeding behaviour of primiparous and multiparous Jersey and Holstein cows kept under equal conditions throughout lactation.

The objective of the study was to describe the feeding behaviour of primiparous and multiparous Jersey cows compared to Holstein cows housed in separate groups in the same barn. Such information could help farmers to optimise management with respect to welfare and production. Yet, it remains limited for Jersey cows over the entire period of lactation. Feeding data of 116 Danish Jersey (mean parity 2.14 ± 1.32) and 218 Danish Holstein cows (mean parity 1.90 ± 1.16) were assessed using automatic feeders from day 15 to 252 of lactation. Total eating duration, duration of eating per visit, intervals between meals, number of visits per day and the eating rate were analysed using linear mixed effects models. The cows were kept in a loose-housing system, with cubicles and automatic milking robots, and the group composition was dynamic. Compared to Holstein cows, Jersey cows visited the feeder significantly more often with shorter between meal intervals. However, the visit duration and total daily eating time and eating rates were significantly shorter for Jersey cows. There was no difference between breeds in the daily eating time and eating rate of older cows. Younger Jersey cows had significantly lower eating rates than older Jersey cows. No other difference in parity was found within Jersey cows. Weeks in milk significantly affected the eating time per day, number of visits per day and eating rate. The trajectories of outcome variables during lactation did not differ between the two breeds. In conclusion, we found substantial differences in the feeding behaviour of Jersey and Holstein cows, however, these differences could also be related to a group effect.

Androgen-Dependent Differences in the Amounts of CYP mRNAs in the Pig Kidney.

We previously reported androgen-dependent sex and breed differences in the amounts of mRNAs of CYP isoforms in the pig liver. To clarify whether there are such sex and breed differences in the kidney, we examined the amounts of several CYP mRNAs in the kidney using both sexes of 5-month-old Landrace, Meishan and/or their crossbred F1 (LM and ML) pigs. Significant sex differences in the amounts of several CYP mRNAs were found: male < female for CYP2A19 and CYP3A29; and male > female for CYP4A24/25 in all the breeds. Sex differences in the amount of CYP2B22 mRNA (male < female) and in CYP2C33 and CYP2C49 mRNAs (male > female) were also observed in all the breeds except Landrace pigs. Furthermore, a significant sex difference (male < female) in CYP3A46 mRNA was only found in LM and ML pigs. No significant sex differences were found in either Landrace or Meishan pigs for CYP1A1, CYP1A2 and CYP4B1 mRNAs. The amounts of CYP2C33 and CYP4A24/25 mRNAs in males were higher in Meishan pigs than in Landrace pigs. Additional experiments using pigs treated by castration and/or testosterone propionate indicated that sex and breed differences in the amounts of those CYP mRNAs were, at least in part, dependent on the levels of serum testosterone. Furthermore, the effects of androgen on the amounts of CYP mRNAs in the kidney did not necessarily correlate with those in the liver, suggesting that there is a tissue-selective factor responsible for the androgen-related expression of CYP genes.

Genetic analysis of orotic acid predicted with Fourier transform infrared milk spectra.

Fourier transform infrared spectral analysis is a cheap and fast method to predict milk composition. A not very well studied milk component is orotic acid. Orotic acid is an intermediate in the biosynthesis pathway of pyrimidine nucleotides and is an indicator for the metabolic cattle disorder deficiency of uridine monophosphate synthase. The function of orotic acid in milk and its effect on calf health, health of humans consuming milk or milk products, manufacturing properties of milk, and its potential as an indicator trait are largely unknown. The aims of this study were to determine if milk orotic acid can be predicted from infrared milk spectra and to perform a large-scale phenotypic and genetic analysis of infrared-predicted milk orotic acid. An infrared prediction model for orotic acid was built using a training population of 292 Danish Holstein and 299 Danish Jersey cows, and a validation population of 381 Danish Holstein cows. Milk orotic acid concentration was determined with nuclear magnetic resonance spectroscopy. For genetic analysis of infrared orotic acid, 3 study populations were used: 3,210 Danish Holstein cows, 3,360 Danish Jersey cows, and 1,349 Dutch Holstein Friesian cows. Using partial least square regression, a prediction model for orotic acid was built with 18 latent variables. The error of the prediction for the infrared model varied from 1.0 to 3.2 mg/L, and the accuracy varied from 0.68 to 0.86. Heritability of infrared orotic acid predicted with the standardized prediction model was 0.18 for Danish Holstein, 0.09 for Danish Jersey, and 0.37 for Dutch Holstein Friesian. We conclude that milk orotic acid can be predicted with moderate to good accuracy based on infrared milk spectra and that infrared-predicted orotic acid is heritable. The availability of a cheap and fast method to predict milk orotic acid opens up possibilities to study the largely unknown functions of milk orotic acid.

Genome-wide association study on Fourier transform infrared milk spectra for two Danish dairy cattle breeds.

BACKGROUND: Infrared spectral analysis of milk is cheap, fast, and accurate. Infrared light interacts with chemical bonds present inside the milk, which means that Fourier transform infrared milk spectra are a reflection of the chemical composition of milk. Heritability of Fourier transform infrared milk spectra has been analysed previously. Further genetic analysis of Fourier transform infrared milk spectra could give us a better insight in the genes underlying milk composition. Breed influences milk composition, yet not much is known about the effect of breed on Fourier transform infrared milk spectra. Improved understanding of the effect of breed on Fourier transform infrared milk spectra could enhance efficient application of Fourier transform infrared milk spectra. The aim of this study is to perform a genome wide association study on a selection of wavenumbers for Danish Holstein and Danish Jersey. This will improve our understanding of the genetics underlying milk composition in these two dairy cattle breeds. RESULTS: For each breed separately, fifteen wavenumbers were analysed. Overall, more quantitative trait loci were observed for Danish Jersey compared to Danish Holstein. For both breeds, the majority of the wavenumbers was most strongly associated to a genomic region on BTA 14 harbouring DGAT1. Furthermore, for both breeds most quantitative trait loci were observed for wavenumbers that interact with the chemical bond C-O. For Danish Jersey, wavenumbers that interact with C-H were associated to genes that are involved in fatty acid synthesis, such as AGPAT3, AGPAT6, PPARGC1A, SREBF1, and FADS1. For wavenumbers which interact with -OH, associations were observed to genomic regions that have been linked to alpha-lactalbumin. CONCLUSIONS: The current study identified many quantitative trait loci that underlie Fourier transform infrared milk spectra, and thus milk composition. Differences were observed between groups of wavenumbers that interact with different chemical bonds. Both overlapping and different QTL were observed for Danish Holstein and Danish Jersey.

Genetic analysis of Fourier transform infrared milk spectra in Danish Holstein and Danish Jersey.

Fourier transform infrared milk spectral data are routinely used for milk quality control and have been revealed to be driven by genetics. This study aimed to (1) estimate heritability for 1,060 wavenumbers in the infrared region from 5,008 to 925 cm-1, (2) estimate genomic correlations between wavenumbers with increased heritability, and (3) compare results between Danish Holstein and Danish Jersey cows. For Danish Holstein, 3,275 cows and 19,656 milk records were available. For Danish Jersey, 3,408 cows and 20,228 milk records were available. We used a hierarchical mixed model, with a Bayesian approach. Heritability of individual wavenumbers ranged from 0.00 to 0.31 in Danish Holstein, and from 0.00 to 0.30 in Danish Jersey. Genomic correlation was calculated between 15 selected wavenumbers, and varied from weak to very strong, in both Danish Holstein and Danish Jersey (0.03 to 0.97, and -0.11 to -0.97). Within the 15 selected wavenumbers, a subdivision into 2 groups of wavenumbers was observed, where genomic correlations were negative between groups, and positive within groups. Heritability and genomic correlations were higher in Danish Holstein compared with Danish Jersey, but followed a similar pattern in both breeds. Breed differences were most pronounced in the mid-infrared region that interacts with lactose and the spectral region that interacts with protein. In conclusion, heritability for individual wavenumbers of Fourier transform milk spectra was moderate, and strong genomic correlations were observed between wavenumbers across the spectrum. Heritability and genomic correlations were higher in Danish Holstein, with the strongest breed differences showing in spectral regions interacting with protein or lactose.

Genetic heterogeneity of feed intake, energy-corrected milk, and body weight across lactation in primiparous Holstein, Nordic Red, and Jersey cows.

In this study, we aimed to estimate and compare the genetic parameters of dry matter intake (DMI), energy-corrected milk (ECM), and body weight (BW) as 3 feed efficiency-related traits across lactation in 3 dairy cattle breeds (Holstein, Nordic Red, and Jersey). The analyses were based on weekly records of DMI, ECM, and BW per cow across lactation for 842 primiparous Holstein cows, 746 primiparous Nordic Red cows, and 378 primiparous Jersey cows. A random regression model was applied to estimate variance components and genetic parameters for DMI, ECM, and BW in each lactation week within each breed. Phenotypic means of DMI, ECM, and BW observations across lactation showed to be in very similar patterns between breeds, whereas breed differences lay in the average level of DMI, ECM, and BW. Generally, for all studied breeds, the heritability for DMI ranged from 0.2 to 0.4 across lactation and was in a range similar to the heritability for ECM. The heritability for BW ranged from 0.4 to 0.6 across lactation, higher than the heritability for DMI or ECM. Among the studied breeds, the heritability estimates for DMI shared a very similar range between breeds, whereas the heritability estimates for ECM tended to be different between breeds. For BW, the heritability estimates also tended to follow a similar range between breeds. Among the studied traits, the genetic variance and heritability for DMI varied across lactation, and the genetic correlations between DMI at different lactation stages were less than unity, indicating a genetic heterogeneity of feed intake across lactation in dairy cattle. In contrast, BW was the most genetically consistent trait across lactation, where BW among all lactation weeks was highly correlated. Genetic correlations between DMI, ECM, and BW changed across lactation, especially in early lactation. Energy-corrected milk had a low genetic correlation with both DMI and BW at the beginning of lactation, whereas ECM was highly correlated with DMI in mid and late lactation. Based on our results, genetic heterogeneity of DMI, ECM, and BW across lactation generally was observed in all studied dairy breeds, especially for DMI, which should be carefully considered for the recording strategy of these traits. The genetic correlations between DMI, ECM, and BW changed across lactation and followed similar patterns between breeds.

Interbreed variation in serum serotonin (5-hydroxytryptamine) concentration in healthy dogs.

INTRODUCTION: Serotonin (5-hydroxytryptamine [5-HT]) has several biological functions. In different species, excessive 5-HT has been linked to valvular lesions, similar to those seen in dogs with myxomatous mitral valve disease. Previous studies suggest higher 5-HT in healthy Cavalier King Charles Spaniels (CKCSs), a breed highly affected by myxomatous mitral valve disease, compared to other breeds. OBJECTIVE: To investigate potential interbreed variation in serum 5-HT in healthy dogs. ANIMALS: 483 healthy dogs of nine breeds aged 1-7 years. METHODS: Dogs were examined at five European centers. Absence of cardiovascular, organ-related, or systemic diseases was ensured by thorough clinical investigations including echocardiography. Serum was frozen and later analyzed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Median 5-HT concentration was 252.5 (interquartile range = 145.5-390.6) ng/mL. Overall breed difference was found (p<0.0001), and 42% of pairwise breed comparisons were significant. Univariate regression analysis showed association between serum 5-HT concentration and breed, center of examination, storage time, and sex, with higher 5-HT in females. In multiple regression analysis, the final model had an adjusted R2 of 0.27 with breed (p<0.0001), center (p<0.0001), and storage time (p=0.014) remaining significant. Within centers, overall breed differences were found at 3/5 centers (p≤0.028), and pairwise comparisons within those centers showed breed differences in 42% of comparisons. Among the included breeds, Newfoundlands, Belgian Shepherds and CKCSs had highest 5-HT concentrations. CONCLUSIONS: Interbreed variation in serum 5-HT concentration was found in healthy dogs aged 1-7 years. These differences should be taken into account when designing clinical studies.

Expression analyses of candidate genes related to meat quality traits in squabs from two breeds of meat-type pigeon.

In this study, meat quality traits were compared between squabs from two pigeon breeds: one Chinese indigenous breed, the Shiqi (SQ) meat-type pigeon, and an imported breed, the white king (WK) meat-type pigeon. Breed differences were detected in the content of intramuscular fat (IMF) in the breast muscle. SQ squabs had significantly higher IMF content than the WK birds. The shear force value (an objective measure of meat tenderness) of SQ birds was also relatively lower than that of the WK squabs. Further analysis of fatty acids profile revealed that SQ squabs exhibited significant advantage in the synthesis of polyunsaturated fatty acids, while WK squabs were significantly higher in the sum of monounsaturated fatty acids. Breast muscle in the SQ squabs was also significantly higher in the ratio of polyunsaturated fatty acids to saturated fatty acids, as well as the sum of omega 6 fatty acids. Variability of expression levels of functional genes in relation to fat accumulation and meat tenderness was analysed by qRT-PCR. Gene expression analyses showed that the hepatic expression of LPL (lipoprotein lipase), FABP4 (fatty acid-binding protein 4), and CAPN2 (calpain-2) were significantly higher in the SQ squabs. In the breast muscle tissue, the FABP3 (fatty acid-binding protein 3) and CAPN2mRNA abundance was significantly higher in SQ squabs. Our results suggested that these differentially expressed genes might be candidate genes used in the programmes of targeted selection for squabs with higher IMF content, tender meat, and more favourable fatty acids composition.

Polymorphisms in the canine monoamine oxidase a (MAOA) gene: identification and variation among five broad dog breed groups.

BACKGROUND: In humans, reduced activity of the enzyme monoamine oxidase type A (MAOA) due to genetic polymorphisms within the MAOA gene leads to increased brain neurotransmitter levels associated with aggression. In order to study MAOA genetic diversity in dogs, we designed a preliminary study whose objectives were to identify novel alleles in functionally important regions of the canine MAOA gene, and to investigate whether the frequencies of these polymorphisms varied between five broad breed groups (ancient, herding, mastiff, modern European, and mountain). Fifty dogs representing these five breed groups were sequenced. RESULTS: A total of eleven polymorphisms were found. Seven were single nucleotide polymorphisms (SNPs; two exonic, two intronic and three in the promoter), while four were repeat intronic variations. The most polymorphic loci were repeat regions in introns 1, 2 (7 alleles) and 10 (3 alleles), while the exonic and the promoter regions were highly conserved. Comparison of the allele frequencies of certain microsatellite polymorphisms among the breed groups indicated a decreasing or increasing trend in the number of repeats at different microsatellite loci, as well as the highest genetic diversity for the ancient breeds and the lowest for the most recent mountain breeds, perhaps attributable to canine domestication and recent breed formation. While a specific promoter SNP (-212A > G) is rare in the dog, it is the major allele in wolves. Replacement of this ancestral allele in domestic dogs may lead to the deletion of heat shock factor binding sites on the MAOA promoter. CONCLUSIONS: Dogs exhibit significant variation in certain intronic regions of the MAOA gene, while the coding and promoter regions are well-conserved. Distinct genetic differences were observed between breed groups. Further studies are now required to establish whether such polymorphisms are associated in any way with MAOA level and canine behaviour including aggression.

Gross anatomy and morphometric evaluation of the canine lacrimal and third eyelid glands.

OBJECTIVE: The lacrimal gland (LG) and the third eyelid gland (TELG) are two intraorbital glands that, in dogs, secrete the aqueous component of the tear film. Despite the central importance of these structures for maintaining ocular surface health, the gross anatomy of the glands remains understudied. We investigated the macroscopic morphometric characteristics of the LG and TELG in three different dog breeds. PROCEDURES: Twenty-six dog heads were dissected to expose the LG and TELG; the length, width, thickness, and weight of each were measured. During the dissections, the relationships between the glands and adjacent ocular structures and the blood and nerve supplies to the LG were photo-documented. RESULTS: The LG had a flat and irregular shape with morphological variations among dogs. The LG was located on the dorsolateral aspect of the globe underneath the orbital ligament. The average length, width, and thickness (SEM) of the LG (mm) were 16.5 ± 0.7, 12.5 ± 0.4, and 2.7 ± 0.1 and of the TELG 10.5 ± 0.6, 11.0 ± 0.3, and 3.3 ± 0.1, respectively. The mean weights (SD) of the LG and TELG (mg) were 315.7 ± 21.1 and 263.3 ± 13.2, respectively. Beagles were observed to have significantly smaller LGs compared to pit bull terriers and pointer mixed-breed dogs. CONCLUSIONS: The present study provides detailed normative anatomical and morphometric data for the LG and TELG. These data will aid researchers investigating alterations induced by disease states and should inform strategies for the local delivery of pharmacologic and cellular therapeutics.

Individual difference in serum oxytocin concentrations of calves and the correlation with those in dams.

We examined individual differences in serum oxytocin concentrations (OT) of calves, and assessed whether these differences were correlated with their dams' milk and serum OT. Eight Holstein (H), nine Japanese Shorthorn (JS), and six Japanese Black (JB) calves were examined. Blood was collected three times during the first month in H calves, while their dams' blood was collected three times prior to parturition. Milk was collected twice after parturition from H cows. Blood from JS and JB calves were collected at 1 and 4 months old, while of their dams only once before parturition. Serum OT in H calves at 7 days old was significantly correlated with that at 30 days. Serum OT of JS calves at 1 month old was significantly correlated to that at 4 months, while of JB calves was also positively correlated (r = 0.70). Serum OT of calves showed significant individual differences in each breed. Serum OT of calves was not correlated with the milk OT of dams, except for 3-day-old calves that fed on their dams' milk. We concluded that although serum OT differed among individuals, this difference was stable within each individual and not affected by the serum OT of the dams.

Breed Differences in Dopamine Receptor D4 Gene (DRD4) in Horses.

Genetic polymorphisms in genes related to neurotransmitters or hormones affect personality or behavioral traits in many animal species including humans. In domestic animals, the allele frequency of such genes has been reported to be different among breeds and it may account for breed differences in behavior. In this study, we investigated breed differences in horses in the dopamine receptor D4 gene (DRD4), which has been reported to affect horse personality. We collected samples from seven horse breeds including those native to Japan and Korea, and compared the sequence of the DRD4 exon3 region among these breeds. We found that there were two types of polymorphisms (VNTR and SNPs) in the exon3 region, and some of them seemed to be breed-specific. In addition, we found that the allele frequency of G292A, reported to be associated with horse personality, differed greatly between native Japanese horses and Thoroughbred horses. The frequency of the A allele which is associated with low curiosity and high vigilance, was much lower in native Japanese horses (Hokkaido, 0.03; Taishu, 0.08) than in Thoroughbreds (0.62). This difference may account for breed differences in personality or behavioral traits. Further studies of the function of these polymorphisms and their effect on behavior are indicated.