Erling Strandberg

Studying canine behavioral genetics could provide important insights for dog breeding and for understanding both canine and human behavior. To identify genetic determinants of behavior in German Shepherd Dogs, we used a cohort of 373 dogs to search for genome‐wide associations with behavioral variables and personality traits measured by the Dog Mentality Assessment (DMA), a standardized dog behavior evaluation widely used in Sweden. Multidimensional scaling using genetic data revealed two clusters identified by merits as working and show sub‐populations differing in most of their DMA scores. These behavioral differences were strongly correlated with BOLDNESS—a higher‐order trait considered a measure of the shyness‐boldness personality continuum in dogs. A region with highest allele frequency differences between sub‐populations was found on CFA24: 23.5–25.5 Mb containing genes for coat color specification and previously reported candidate regions of selection. The strongest association signals were found for traits/behavioral variables correlating with BOLDNESS as, for example, on CFA1 within a region encompassing the TCF4 gene for which, in humans, multiple associations with neuroticism (a reverse equivalent in humans of BOLDNESS in dogs) were reported. Signals of association were found in regions containing genes with important roles in the nervous system and associations with comparable personality traits, such as neuroticism, in humans. Our results indicate that within‐breed selection in GSDs has had an effect on the shyness‐boldness personality continuum, with working dogs scoring higher in all aspects of BOLDNESS—being more playful, prone to chase after toys, curious, fearless and socially interested in strangers compared with show dogs.

Background: Lameness is the most common health problem in riding horses, and insurance data have previously been used to investigate the prevalence of orthopaedic diagnoses in Swedish Warmblood (SWB) horses. Young horse performance testing is an important part of the SWB breeding programme and contributes data to the genetic evaluation. Assessed traits from these tests have been shown to be useful indicator traits of performance in show jumping and dressage, but their associations with orthopaedic health have not previously been investigated. Objectives: To study the associations between assessed traits from young horse tests and orthopaedic diagnoses, and to investigate if such traits can be useful as indicator traits of future orthopaedic health in SWB horses. Study Design: Retrospective cohort study. Methods: Insurance data from 5991 SWB horses between 4 and 14 years, born in 2010–2020, and assessed at a young horse test were included. Horses were classified as jumping or dressage horses. The data were analysed with survival analysis, using the number of days from birth to first orthopaedic diagnosis as time scale. Results: High scores for the numerically scored trait ‘trot at hand’ were significantly associated with less risk of orthopaedic diagnoses for both jumping and dressage horses ( p < 0.05 and p < 0.001, respectively). Also, horses with greater height at the withers had a significantly higher risk of having orthopaedic diagnoses. Eleven of 48 linearly scored traits were significantly associated with orthopaedic diagnoses. Main Limitations: The insurance data may have uncertainties and will not fully describe the prevalence of orthopaedic diagnoses in the SWB population. Additionally, pre‐selection of horses attending young horse tests may introduce some bias in the data on assessed traits. Conclusions: Relatively few traits were significantly associated with orthopaedic diagnoses, suggesting that traits currently assessed at young horse tests have limited value as indicator traits of orthopaedic health.

Background: Idiopathic epilepsy (IE) in Golden Retrievers (GRs) has a suspected genetic basis with several endogenous risk factors potentially affecting the disease, including sex, breed subtypes, and chronic comorbidities. A subdivision into working (W-GRs) and show (S-GRs) Golden Retrievers presents a unique opportunity to investigate possible line-related risk factors. Hypothesis/Objectives: Define prevalence and investigate risk factors for IE in a population of Swedish GRs. We hypothesized a high prevalence of IE in GRs characterized by frequent cluster seizures, with the following representing potential risk factors for IE: subtype W-GR, male, and gastrointestinal or dermatologic signs or both. Animals: Twenty-nine client-owned GRs with IE and 714 controls. Methods: Prospective questionnaire-based study exploring the dog’s health status, living conditions, and possible seizures, including questions regarding seizure characteristics, treatments, and clinical outcomes in affected dogs. Data was analyzed using descriptive and inferential statistics and a logistic regression model was used to estimate the effect of potential risk factors on the probability of IE. Results: The prevalence of IE in GRs was 3.9%, with 48.2% presenting with cluster seizures. A significant difference in prevalence of IE between W-GRs and S-GRs was not found. Being male, showing signs of gastrointestinal disease, and cereal-free diets were associated with increased risk of IE. Conclusions and clinical importance: Golden retrievers have an increased risk of IE, often presenting with cluster seizures. The association between IE and gastrointestinal disease might lead to new therapeutic strategies, but further investigations are needed.

In several European countries, racing without shoes, ie barefoot, is a common strategy in trotting races to improve the speed of the horse. Why some trotters can race barefoot without damage to the hoof from excessive wear and others cannot has been shown to partly be explained by differences in hoof composition. In particular, durable hind hooves are believed to be important to sustain racing without shoes. Also, variation in the proportion of the races the horse races with barefoot hind hooves has been shown to be affected by genetic differences in Swedish Standardbred trotters (SB) and Swedish-Norwegian Coldblooded trotters (CB). When racing barefoot, the protective properties of the shoe, which prevent the hoof from excessive wear and tear, are absent. If the hoof cannot withstand wear and tear, the damage of the hoof may pose a risk to animal welfare. The question of how barefoot racing should be regulated, especially for young horses, is under discussion in Sweden and elsewhere in Europe. Regulations regarding barefoot racing in young horses differ between countries, and there is a lack of published studies to base regulations on. Therefore, this study aimed to analyze the effect of racing with barefoot hind hooves in young SB and CB on career length. Datasets including shoeing information from 3-year-old SB, and 3- and 4-year-old CB were analyzed, including up to 12,161 horses. Cox proportional hazard models were fitted to analyze the effect of proportion of barefoot races at a young age on the hazard of ending the career at a given time point. Other effects such as sex, year of birth, started as a 2-year-old or not (SB only), early earnings, best racing time, and number of early starts were also included in the models. For SB, horses that raced more than 30% barefoot had a 14% higher hazard of ending their career at a given time point compared to the reference group that raced 5% or less barefoot. In CB, the hazard of ending the career at a given time point was 67% higher in the group with the highest proportion of barefoot races compared with the reference group. Although for SB, the reduction of the career length in days was minor. For CB, the effect was larger and verified the negative effect in SB but estimated based on fewer observations. Further studies of voluntary as well as involuntary reasons why Swedish trotters end their careers are needed to better understand the possible impact of racing barefoot as a young horse.

Customized voluntary waiting period (VWP) before first insemination was tested in 18 commercial dairy herds in Sweden, to assess milk production, fertility and health in primiparous cows expected to be suited for extended VWP. Cow selection for extended VWP was based on 3 criteria in early lactation: 1) the 10% of cows with highest genomic persistency index, 2) cows with a difficult calving or disease during the first month of lactation, and 3) cows with higher yield during d 4-33 after calving than the herd average for primiparous cows. Cows meeting at least one of these criteria were randomly assigned to either the ExtExt treatment (extended VWP of at least 175 d, n = 174; calving interval (CInt) = 16.3 mo) or the ExtConv treatment (conventional VWP of maximum 100 d n = 173; CInt = 12.4 mo). Cows not meeting any of the criteria were assigned to the ConvConv treatment (conventional VWP, n = 183; CInt = 12.0 mo). There were no differences in milk yield per day in the CInt between treatments, although 305-d and whole-lactation (WL) milk yields were higher for ExtExt cows (10,371 and 13,803 kg) than ExtConv cows (9,812 and 10,257 kg). Milk yield at the last test milking before dry-off was lower in ExtExt compared with ExtConv cows (24.9 vs 28.3), however the results showed no difference in dry period length between the treatments. Regarding reproductive performance, the ExtExt cows had higher first service conception rate (FSCR; 60% vs. 45%) and lower number of inseminations per conception (NINS; 1.67 vs. 2.19), compared with the ExtConv cows. As expected, ConvConv cows had the lowest milk yield in 305-d, in WL, and per day in the CInt, however, FSCR and NINS did not differ between ConvConv cows and cows in the other 2 VWP treatments. Disease incidence was higher for cows in the ExtConv compared with the ConvConv treatment, but there was no difference between ExtExt and the 2 other VWP treatments. Further, no difference in proportion of cows with good udder health or culling rate was detected between any of the treatments, though due to low prevalence the study lacked power to draw major conclusions on these results. Thus prolonging VWP for suitable primiparous cows can produce benefits such as improved fertility in the form of higher FSCR and lower NINS, as well as lower dry-off yield, without compromising milk yield or prolonging dry period length.

Introduction: The use of dairy x dairy crossbreeding has increased in Sweden. This study aimed to compare crosses between Swedish Red (R), Holstein (H), Jersey (J), and Montbéliarde (M) to purebred R, H, and J for fertility, calving, production, and survival traits. The focus was on F1 crosses between either H or R on the one hand and J or M on the other hand, but three-breed crosses were also studied. Material and methods: There were 2,154,241 observations collected from the official cattle recording database for cows that calved between 2005 and 2020 in 7,390 herds. The dataset was separated into first and second parity and analyzed using a mixed linear model including fixed effects of breed group, herd, and year-season and a random effect of herd-year. Results and discussion: Fertility traits were improved in the F1 crosses with J or M compared with R or H (i.e., JR and MR vs. R; JH and MH vs. H), especially in the first parity. In parity 2, the difference was often not significant. Crossing R or H with Jersey gave lower calving difficulty than in the pure breeds in the first parity. However, crossing with Montbéliarde rather tended to give slightly more calving difficulties, albeit not significantly so. Generally, there was no significant change in stillbirths when crossing purebred R or H with J or M. There was a general tendency for better survival in the F₁-crosses, however, only significantly so for Jersey crosses in parity 2 with respect to R or H. F₁ between J and H (JH) had a higher 305-day fat yield than H, but lower milk and protein yields. MH had higher fat and protein yields than H and MR had higher 305-d milk and protein yields than R. In conclusion, crossing R or H with either Jersey or Montbéliarde can be expected to improve fertility and probably also survival. Depending on the current situation, one could choose to improve fat yield (crossing with J) or protein yield (crossing with M), however, depending on the breed, there could be a trade-off, e.g., in milk yield. For other traits, one would not expect any deterioration.