Automated activity monitoring and visual observation of estrus in a herd of loose housed Hereford cattle: Diagnostic accuracy and time to ovulation.

A prospective cohort study was performed in the purebred Hereford herd at Götala Beef and Lamb Research Centre, Sweden. The study's first objective was to assess the ability of an automatic activity monitoring system (AAMS) to detect estrus in beef suckler cows, and its second objective was to estimate the time from estrus to ovulation. The study sample (n = 38) consisted of 14 Hereford heifers and 24 Hereford cows. Standardized visual observation of estrus was performed for 20 minutes thrice daily, and animal activity was recorded with an AAMS system, Heatime (SCR Engineers Ltd., Israel). Cows in estrus underwent transrectal ultrasonography every 8 hours, to estimate the time of ovulation. Blood samples for progesterone analysis were collected thrice weekly throughout the study period. A cutoff value of 1-ng progesterone/mL of serum was used to define luteal activity. The AAMS had a 90% (95% confidence interval [CI] 77%-97%) sensitivity and 100% specificity (95% CI 94%-100%), and visual detection of estrus had a 77% sensitivity (95% CI 62%-88%) and a 89% specificity (95% CI 79%-95%) for identifying estrus when compared to the gold standard defined by temporal pattern of serum progesterone concentration. When both methods were used in parallel, the sensitivity increased to 96% (95% CI 86%-99%), and the specificity increased to 90% (95% CI 80%-96%). The time of ovulation after estrus was determined on 50 occasions. The median estrus (AAMS detected) to ovulation interval was 25 hours for heifers and 23 hours for cows (interquartile range 11-29 hours and 19-25 hours, respectively). The median estrus (visually detected) to ovulation interval was 28 hours for heifers and 21 hours for cows (interquartile range 13-29 hours for both categories). In conclusion, the AAMS had both a higher sensitivity and specificity for estrus detection than thrice-daily visual observation. The time from detection of estrus to ovulation observed in this study indicates that reproductive performance might be improved if Hereford cattle are inseminated sooner after detection of estrus than is currently recommended.

Effects of litter provision during early rearing and environmental enrichment during the production phase on feather pecking and feather damage in laying hens.

Feather pecking is a multi-factorial behavioral disorder and a serious welfare issue in the poultry industry. Several studies report early life experience with litter to be a major determinant in the development of feather pecking. The current study aimed to test the large-scale on-farm efficiency of a simple and cheap husbandry procedure applied during the rearing period with the ultimate goal of reducing the incidence of feather pecking and plumage damage during the production stage in laying hens. Five laying hen-rearing farmers from across Norway participated in the study. These farmers were asked to create divisions within their hen rearing houses and to separate their chicks into 2 groups: one reared with access to a paper substrate from the first d of age, the other a control group without access to paper substrate during rearing. All flocks were visited at the production farms at 30 wk of age and observed for pecking behavior and feather damage. Birds in the control group had higher odds of having more feather damage compared to the birds from the treatment group. In addition, flocks provided with environmental enrichment at the production farms had a reduced incidence of feather pecking, irrespective of the treatment. These results indicate that husbandry procedures during both rearing and production stages have the potential to alleviate feather pecking and increase laying hen welfare.

Comparison of the blood supply to the articular-epiphyseal growth complex in horse vs. pony foals.

REASONS FOR PERFORMING STUDY: To increase understanding of why the prevalence of clinical/radiographic osteochondrosis (OC) dissecans is high in horses and low in ponies. OBJECTIVES: To investigate whether the clinical difference in OC occurrence between horses and ponies could partly be explained by a difference in: 1) number of patent vessels in the epiphyseal growth cartilage; 2) duration of the presence of patent cartilage canals; or 3) growth cartilage thickness at predilection sites for OC. The hypothesis was that pony foals would have fewer cartilage canals, shorter duration of blood supply and thinner growth cartilage than horse foals. STUDY DESIGN: Observational, cross-sectional study. METHODS: Nine Standardbred foals (horse group) 1-49 days old and 11 Norwegian Fjord foals (pony group) 1-62 days old were included. A total of 15 anatomical locations in the tarsocrural and metatarsophalangeal joints were examined by one or more of the following techniques: arterial perfusion; photography of cleared specimens; microcomputed tomography; radiography; and histology. The number of cartilage canals was counted. Cartilage thickness was measured. Duration of blood supply was assessed in histological sections. RESULTS: Of the 3 common predilection sites for OC investigated, there were significantly fewer vessels (P = 0.003) and thinner cartilage (P = 0.002) at the distal lateral trochlear ridge of the talus in the pony group. There was no difference in the duration of presence of cartilage canals between the groups. CONCLUSION: The hypothesis that pony foals would have fewer cartilage canals and thinner growth cartilage than horse foals was confirmed for the lateral trochlear ridge of the talus. The current results may contribute towards an explanation for the low prevalence of OC at the distal lateral trochlear ridge of the talus in pony foals.

A cohort study of epilepsy among 665,000 insured dogs: incidence, mortality and survival after diagnosis.

The main objective of this study was to estimate the incidence and mortality rates of epilepsy in a large population of insured dogs and to evaluate the importance of a variety of risk factors. Survival time after a diagnosis of epilepsy was also investigated. The Swedish animal insurance database used in this study has previously been helpful in canine epidemiological investigations. More than 2,000,000 dog-years at-risk (DYAR) were available in the insurance database. In total, 5013 dogs had at least one veterinary care claim for epilepsy, and 2327 dogs were euthanased or died because of epilepsy. Based on veterinary care claims the incidence rate of epilepsy (including both idiopathic and symptomatic cases) was estimated to be 18 per 10,000 DYAR. Dogs were followed up until they were 10 (for life insurance claims) or 12 years of age (veterinary care claims). Among the 35 most common breeds in Sweden, the Boxer was at the highest risk of epilepsy with 60.3 cases per 10,000 DYAR, and also had the highest mortality rate of 46.7 per 10,000 DYAR (based on life insurance claims). Overall, males were at a higher risk than females (1.4:1). Median survival time (including euthanasia and death) after diagnosis was 1.5 years. In general, breeds kept solely for companionship lived longer after diagnosis than those kept for dual-purposes, such as hunting and shepherd and working breeds. The study demonstrates marked breed differences in incidence and mortality rates, which are assumed to reflect genetic predisposition to epilepsy.

The effect of vaccination, ploidy and smolt production regime on pathological melanin depositions in muscle tissue of Atlantic salmon, Salmo salar L.

The presence of melanin in muscle fillets of farmed salmon represents a considerable quality problem for the salmon industry with major economic concerns. In this study, we have examined the presence of abnormal pigmentation in vaccinated versus unvaccinated Atlantic salmon, Salmo salar L., and evaluated possible differences between diploid and triploid fish. Furthermore, the impact of the smolt production regime at ambient (4.5 °C) versus elevated temperature (16 °C) was investigated. Pigmented muscle spots were analysed for the expression of genes involved in melanization (tyrosinase gene family) and immune-related response in addition to morphological investigations. The proportion of fish with intramuscular melanin deposits was not significantly different between vaccinated and unvaccinated fish, regardless of ploidy. However, an interaction between vaccination and smolt regime was shown, where smoltification at elevated temperature after vaccination increased the number of affected individuals compared with vaccination followed by simulated natural smoltification. Furthermore, there were overall more fish with melanin spots amongst the triploids compared with their diploid counterparts. Transcription of the tyrosinase gene family confirmed an onsite melanogenesis in all pigment spots. The histological examination and the expression of the immune-related genes revealed a chronic polyphasic myopathy that was not affected by vaccination, ploidy or smolt production regime.

Effect of ovariohysterectomy at the time of tumor removal in dogs with benign mammary tumors and hyperplastic lesions: a randomized controlled clinical trial.

BACKGROUND: Nonmalignant mammary tumors (NMT) are common in intact female dogs. Little is known about the clinical significance of these tumors, and the effect of ovariohysterectomy (OHE) on their development. HYPOTHESIS: Ovarian hormone ablation through OHE decreases the risk of new tumors and thereby improves long-term prognosis for dogs with NMT. ANIMALS: Eighty-four sexually intact bitches with NMT. METHODS: Dogs were allocated to undergo OHE (n = 42) or not (n = 42) at the time of NMT removal in a randomized clinical trial. Tumor diagnosis was confirmed histologically in all subjects. Information about new tumor development was collected via follow-up phone calls and recheck examinations. Separate survival analyses were performed with the endpoints new tumor development and death. Cause of death was classified as related or unrelated to mammary tumor. In addition to OHE status, the influence of age, body weight, breed, tumor size, tumor number, tumor duration, type of surgery, and tumor histology was investigated. RESULTS: New mammary tumor(s) developed in 27 of 42 (64%) intact dogs and 15 of 42 (36%) ovariohysterectomized dogs (hazard ratio 0.47, P = .022). Nine of the 42 dogs (21%) which developed new tumors were euthanized because of mammary tumor. Survival was not significantly different between the 2 treatment groups. In the intact group, nine dogs subsequently developed ovarian-uterine diseases. CONCLUSION: Ovariohysterectomy performed at the time of mammary tumor excision reduced the risk of new tumors by about 50% among dogs with NMT. Survival was not significantly affected. Adjuvant OHE should be considered in adult dogs with mammary tumors.

The relationship between post-thaw sperm DNA integrity and non-return rate among Norwegian cross-bred rams.

With the aim of investigating the relationship between sperm DNA integrity and non-return rate (NRR) among Norwegian cross-bred rams, semen from 15 individuals was examined by flow cytometry. Sperm Chromatin Structure Assay (SCSA) quantifies the proportion of spermatozoa with denatured DNA after in situ acid treatment, and the four parameters % DFI, % HDS, MEAN DFI and SD DFI are all different measures of DNA denaturation and maturation. Field fertility, reported as NRR 25 days after insemination was based on all inseminations from a large-scale breeding programme and supplied by the Norwegian Association of Sheep and Goat Farmers. From each ram, four straws from four different weeks of the breeding season were analysed, and the associations between 25-day NRR and the mean of the four SCSA parameters were tested using a logistic regression model. The results revealed no association between fertility and % DFI or % HDS, while SD DFI and MEAN DFI showed a significant negative association with NRR. Further, the SCSA values varied significantly between ejaculates within ram among some of the rams in the study. However, no significant association was seen between these intra-individual differences in sperm DNA integrity and NRR. In conclusion, this study suggests an association between sperm DNA integrity and NRR for rams. However, further research must be conducted to confirm these findings and determine whether sperm DNA assessments can be applied to predict ram fertility.

Canine perinatal mortality: a cohort study of 224 breeds.

Canine perinatal mortality is known to be relatively high. However, the literature on perinatal mortality in dogs is still sparse and often refers to a single or only a few breeds. The aim of this large-scale observational study was to describe the perinatal mortality in purebred dogs of various breeds at both puppy and litter level. In addition, the influence of breed, breed size, litter size, age of the bitch, litter number and season for whelping on the risk of perinatal mortality at litter level was studied and the mean litter size at eight days and eight wks after birth was calculated. A retrospective cohort study was performed by studying 10,810 litters of 224 breeds registered in the Norwegian Kennel Club in 2006 and 2007. Perinatal mortality was defined as the sum of stillborn puppies and puppies that died during the first wk after birth (early neonatal mortality) and was present in 24.6% of the litters. Eight percent of the puppies died before eight days after birth, with 4.3% as stillbirth and 3.7% as early neonatal mortality. For most breeds the perinatal mortality was low, but for some breeds a higher perinatal mortality was found. The mean litter size at eight days and eight wks after birth was 4.97 (±0.02) and 4.92 (±0.02) puppies, respectively. Of all puppies born, only 1% died during the period from eight days to eight wks after birth. Random effects logistic regression analysis indicated that increasing litter size and age of the bitch were associated with an increased risk of stillbirth, early neonatal mortality and total perinatal mortality at the litter level (P < 0.001). The random breed effect was significant for all outcomes. Litter number also had a significant effect on stillbirth, early neonatal mortality and total perinatal mortality at the litter level, with the highest risk of perinatal mortality found in the first litter (P < 0.001). Further, the risk of early neonatal mortality was doubled in litters with stillborn puppies. No significant effect of whelping season on perinatal mortality at litter level was found. An interaction existed between the age of the bitch and litter number and the risk of stillbirth was three times as high (odds ratio = 3.00) in litters from bitches having their first litter after the age of six y. Breed was a more important determinant of perinatal mortality in litters than breed size. However, more than 90% of the variation in perinatal mortality was found at the individual litter level and efforts to minimize puppy mortality should be targeted at the management of the individual litter rather than at the breed level.

Current status of canine cancer registration - report from an international workshop.

This is a report from a workshop on canine cancer registration hosted at the Norwegian School of Veterinary Science in Oslo in August 2010. The aim is to present a summary of the current efforts to gather data on canine (and feline) cancer based on information from participants at the workshop. A definition and classification of cancer registries is provided together with an inventory of the databases presented. Particular focus is placed on the distinction between population-based and hospital-based cancer registries. Future challenges are discussed and issues relating to harmonization of diagnostic coding, defining the population-at-risk, individual animal identification and data quality are included. Finally, other groups working within the field of cancer registration in companion animals are encouraged to contact the authors for future collaboration.

Inherited polyneuropathy in Leonberger dogs.

BACKGROUND: Although reporting the same clinical phenotype, inherited polyneuropathy in Leonberger dogs (ILPN) has been attributed to various modes of inheritance. HYPOTHESIS: The ILPN is one disease with a major risk factor on chromosome X. ANIMALS: Dogs affected by ILPN (n = 104). METHODS: Pedigree analyses were performed by means of a case-control approach. Data were retrieved either from medical records of cases diagnosed by the first author (n = 13), from breeders (n = 18) or from different registries publishing data on affected dogs (n = 73). A comparison was made between the X-chromosome ancestry of fathers of affected male dogs and the ancestry of the X-chromosomes of mothers of affected dogs of either sex. A systematic random sample, obtained from an international database of registered Leonberger dogs, served as a reference population regarding ancestry. RESULTS: Having one particular female, born 1943, in the X-chromosomal lineage is a major risk factor for developing ILPN. Sex distribution among affected dogs is in favor of a risk factor on the X-chromosome and contradicts a monogenic autosomal or mitochondrial inheritance. CONCLUSIONS AND CLINICAL IMPORTANCE: The ILPN is considered most likely to be one disease, and the inheritance of ILPN is best explained by an underlying X-linked mode of transmission for the phenotype. However, age at onset and severity of signs might be determined by contributing loci. This has consequences in molecular genetic studies and for breeding strategies aimed at eliminating this disease.

Breed differences in the proportional morbidity of testicular tumours and distribution of histopathologic types in a population-based canine cancer registry.

Histologically verified tumours submitted to the Norwegian Canine Cancer Register from 1990 to 1998 were studied (n=14,401). The proportion of testicular tumours (n=345) was 2.4%, and the breakdown of histological tumour diagnoses is presented. The frequency of the most common histopathological types was 33% interstitial (Leydig), 26.4% Sertoli and 33.9% seminomas/germ cell tumours. The average age at diagnosis was 10 years, but was significantly lower for Sertoli cell tumours (8.6 years) than for the other tumour types. Following a histopathological re-evaluation, 22.5% of the original tumor diagnoses were modified. Proportional morbidity ratios were calculated and individuals from the breeds Shetland sheepdog and Collie were five times more likely to have testicular tumours than the overall average for the registry. Breed differences in the distribution of histopathologic types were observed. Shetland sheepdog and Collie were most commonly diagnosed with Sertoli cell tumours, while all tumours from Norwegian elkhound in this material were seminomas.

Mortality of life-insured Swedish cats during 1999-2006: age, breed, sex, and diagnosis.

BACKGROUND: A cat life insurance database can potentially be used to study feline mortality. HYPOTHESIS: The aim was to describe patterns of mortality in life-insured Swedish cats. Cats: All cats (<13 years of age) with life insurance during the period 1999-2006 were included. METHODS: Age-standardized mortality rates (MR) were calculated with respect to sex (males and females), age, breed, and diagnosis. Survival to various ages is presented by time period and breed. RESULTS: The total number of cats insured was 49,450 and the number of cat-years at risk (CYAR) was 142,049. During the period, 6,491 cats died and of these 4,591 cats (71%) had a diagnosis, ie, were claimed for life insurance. The average annual MR was 462 deaths per 10,000 CYAR (95% confidence interval, 431-493). Sex-specific rates did not differ significantly. The overall mortality of the Persian and the Siamese groups was higher than that of several other breeds. Overall and breed-specific (for most breeds) survival increased with time when analyzed by 2-year periods. The 6 most common diagnostic categories (ignoring cats recorded as dead with no diagnosis) were urinary, traumatic, neoplastic, infectious, cardiovascular, and gastrointestinal. The MR within diagnostic categories varied by age and breed. CONCLUSIONS AND CLINICAL IMPORTANCE: In this mainly purebred, insured cat population, the overall mortality varied with age and breed but not with sex. The increase in survival over time is likely a reflection of willingness to keep pet cats longer and increased access to and sophistication of veterinary care.

Incidence of and risk factors for atopic dermatitis in a Swedish population of insured dogs.

The incidence of atopic dermatitis was estimated to be 1.7 cases per 1000 dog-years at risk in a population of insured Swedish dogs whose insurance claims for the period 1995 to 2002 were examined. Several factors were found to increase the risk of having a recorded claim, including living in a city or in central or southern Sweden, being born in the autumn, and belonging to a high-risk breed. Bull terriers had the highest risk, with 21 cases per 1000 dog-years at risk, and several other breeds including boxers and West Highland white terriers also had an above average risk. There was no difference in the incidence between the sexes. There was a slight increase in the incidence during the period. In a subset of the data that consisted only of dogs from 15 high-risk breeds, the overall survival appeared to be lower for the dogs that had had an insurance claim for the disease.

The effect of eprinomectin treatment at calving on reproduction parameters in adult dairy cows in Canada.

A clinical trial was carried out in two provinces of Canada to investigate the effect of treatment with eprinomectin at calving on production parameters in adult dairy cattle in 1999-2000. One of the objectives of this study was to evaluate the impact of treatment on reproductive performance as measured by: calving-to-conception interval, calving-to-first service interval and number of services per conception. The ability of an indirect ELISA using a crude adult Ostertagia ostertagi antigen to predict response to treatment also was evaluated. All lactating cows in 20 dairy herds were allocated randomly to receive either eprinomectin pour-on or placebo at calving. Information on reproductive parameters was obtained from computerised cow records. Survival models were used to evaluate the effect of treatment on the two intervals and a Poisson model was used to evaluate the number of services to conception. A total of 549 cows were included in these analyses. A marginally significant treatment effect on calving-to-conception interval was observed (hazard ratio=1.24, P=0.06) but not on calving-to-first service interval. A significant reduction in the number of breedings to conception for treated animals also was observed with a longer effect in cows with short interval to first service. Milk samples from a subset of 109 late-lactation cows were tested for antibodies against O. ostertagi. The ELISA optical-density ratio (ODR) values obtained between 120 days before calving and drying off were categorised as high ODR (>or=0.5) and low ODR (<0.5). Among untreated animals, the hazard of conception was lower (hazard ratio=0.38, 95% CI=[0.19,0.75]) for high-ODR cows compared to low ODR cows suggesting that higher parasite burdens had an adverse effect on reproductive performance. Treated high-ODR cows had a hazard of conception equivalent to the hazard for all cows in the low-ODR group (indicating that treatment prevented the negative effect associated with these higher parasite burdens).

[Social class and birth weight]. / Sosial klasse og fødselsvekt.

The aim of this study was to investigate whether the birthweight of Scandinavian children varies according to the social class of their parents, especially the mother. Data were taken from the Scandinavian part of an international multicentre study of fetal growth and perinatal outcome. The occupations of the pregnant woman, her spouse and her parents were registered according to the Nordic classification of occupations. This classification has been criticised for being too detailed to be suitable in epidemiological studies, and the data were recorded into the British system of five classes. The birthweight of female newborns in social class V was 301 g lower than in the other social classes (p < 0.05). A corresponding difference was not shown among male newborns. Newborns of women that had migrated downwards in the socioeconomic system, were 117 g lower than if the migration was upwards (p < 0.05). This difference among female newborns was 164 g (p < 0.05). This study demonstrated that there are differences in birthweight according to social class. This may partly be due to genetic factors and a higher prevalence of smoking and high body mass index, i.e. a less favourable lifestyle in the lower social classes.