Factors associated with average daily gain, fever and lameness in beef bulls at the Saskatchewan Central Feed Test Station.

Data obtained from the Saskatchewan Central Feed Test Station in Saskatoon, Saskatchewan, Canada were examined for evidence of factors related to average daily gain and the diseases occurring in 326 beef bulls during the 1983-84 test. Average daily gain was found to be significantly associated with breed, pen assignment and initial test weight but was not associated with disease or age upon arrival at the test station. Lameness was associated with breed and initial weight, while fever (suspected respiratory disease) was associated with age. The predicted odds of lameness was approximately seven times greater in the animal with the heaviest as compared to the lightest initial test weight and the predicted odds of fever was approximately five times greater in the youngest as compared to the oldest animal.     

THE EFFECT OF PRIOR INFECTION WITH FASCIOLA HEPATICA ON THE RESISTANCE OF SHEEP TO THE SAME PARASITE

The development of flukes that resulted from a challenge dose of 175 F. hepatica metacercariae was compared in 4 groups of sheep that were maintained under grazing conditions on fluke-free pasture. One group had been previously uninfected and all subgroups of each of the other 3 groups had been exposed to one of a range of previous doses of metacercariae. The preliminary infections of 2 of the 3 groups had been terminated respectively after 7 and 14 weeks. The third previously infected group had received its preliminary infection as 2 doses of metacercariae, 7 weeks apart. The latter infection had been terminated after 14 weeks. No appreciable differences in the mean numbers, length, prepatent period or fecundity of flukes, established as a result of the challenge dose of metacercariae, were detected between the control group and the 3 previously infected groups. It was concluded that under the conditions of the present experiment no evidence was detected that would suggest that previous infection with F. hepatica conferred any significant resistance to a future challenge.     

Somatic cell counts, mastitis and milk production in selected Ontario dairy herds.

Somatic cell counts were performed monthly on bulk tank milk samples for all producers in the Ontario counties of Hastings, Lennox/Addington and Prince Edward throughout 1978 and 1979. Other data were obtained via a structured questionnaire and from the records of the Ontario Milk Marketing Board. Many producers have not adopted practices that have been advocated for the integrated control of mastitis. For example, 43.3% of producers surveyed used single service paper towels, 63.3% regularly used teat dip and 56.5% dry cow therapy. The mean of the average monthly somatic cell count for all producers for 1978 was 621.1 x 10(3) cells/mL. This latter value was used to divide the producers into case (higher than average) and control (lower than average) groups. Control herds averaged 95.9 liters more shipped milk per cow per month than case herds. Milk from control herds averaged 0.22 percentage points higher than case herds for each of average fat and lactose, and 0.16 percentage points higher for protein. The linear regression of monthly shipped milk on the respective monthly bulk tank somatic cell count indicated a loss of 13.26 L/cow/month for each 100,000 increase in somatic cell count.     

The interpretation of antimicrobial susceptibility patterns.

The results of a computer model designed to demonstrate the effect of antimicrobial exposure (therapy) on the likelihood of isolating putative pathogens and on the proportion of successfully isolated organisms resistant to specific antimicrobials are presented. The results indicate that the observed percentage resistant is not a reliable indicator of the actual percentage resistant in the source population. Data from the Bruce County Beef Project in 1979-80 are used to verify some of the assumptions used in the model.     

Intraocular silicone prosthesis in a horse

A 40-mm intraocular silicone prosthesis was placed in a horse's globe to control glaucoma. The glaucoma was suspected to be associated with a lens subluxation, but primary glaucoma could not be ruled out. Medical treatment and cyclocryotherapy had been attempted, but failed to decrease the intraocular pressure to a normal value. The prosthesis was placed, via a dorsal scleral incision, after removal of the intraocular contents. The size of the prosthesis was estimated from measurements of the horse's normal left globe and an enucleated, age-matched globe. Silicone prostheses offer a cosmetic alternative to enucleation of blind, sensitive globes in horses.     

The effect of early calfhood health status on survivorship and age at first calving.

Survival to maturity and age at first calving were studied in heifer calves from 34 randomly selected Holstein dairy farms in southwestern Ontario. Calves were divided into cohorts on the basis of treatment for pneumonia, scours, other diseases, or no treatments, during the first 90 days of life. An effect of pneumonia and scours together, over and above the effects of each disease alone, was assessed by means on an interaction term in the statistical analyses. Heifers which had been treated for pneumonia during the first three months of life were 2.5 times more likely to die after 90 days of age than heifers which had not been treated for pneumonia, after controlling for the farm effect. Heifers with a calfhood history of being treated for scours were 2.5 times more likely to be sold for dairy purposes than other calves. Heifers which had been treated for scours were 2.9 times more likely to calve after 900 days of age than other heifers, after controlling for the farm effect.     

Pet ownership increases human risk of encountering ticks

We examined whether pet ownership increased the risk for tick encounters and tickborne disease among residents of three Lyme disease‐endemic states as a nested cohort within a randomized controlled trial. Information about pet ownership, use of tick control for pets, property characteristics, tick encounters and human tickborne disease were captured through surveys, and associations were assessed using univariate and multivariable analyses. Pet‐owning households had 1.83 times the risk (95% CI = 1.53, 2.20) of finding ticks crawling on and 1.49 times the risk (95% CI = 1.20, 1.84) of finding ticks attached to household members compared to households without pets. This large evaluation of pet ownership, human tick encounters and tickborne diseases shows that pet owners, whether of cats or dogs, are at increased risk of encountering ticks and suggests that pet owners are at an increased risk of developing tickborne disease. Pet owners should be made aware of this risk and be reminded to conduct daily tick checks of all household members, including the pets, and to consult their veterinarian regarding effective tick control products.     

Selenium hyperaccumulation offers protection from cell disruptor herbivores

Background  

Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae).     

EFFECTS OF ANESTHETIC PROTOCOL ON NORMAL CANINE BRAIN UPTAKE OF 18F‐FDG ASSESSED BY PET/CT

The purpose of this study was to assess the effects of four anesthetic protocols on normal canine brain uptake of 2‐deoxy‐2‐[¹⁸F]fluoro‐d ‐glucose (FDG) using positron emission tomography/computed tomography (PET/CT). Five clinically normal beagle dogs were anesthetized with (1) propofol/isoflurane, (2) medetomidine/pentobarbital, (3) xylazine/ketamine, and (4) medetomidine/tiletamine–zolazepam in a randomized cross‐over design. The standard uptake value (SUV) of FDG was obtained in the frontal, parietal, temporal and occipital lobes, cerebellum, brainstem and whole brain, and compared within and between anesthetic protocols using the Friedman test with significance set at P<0.05. Significant differences in SUVs were observed in various part of the brain associated with each anesthetic protocol. The SUV for the frontal and occipital lobes was significantly higher than in the brainstem in all dogs. Dogs receiving medetomidine/tiletamine–zolazepam also had significantly higher whole brain SUVs than the propofol/isoflurane group. We concluded that each anesthetic protocol exerted a different regional brain glucose uptake pattern. As a result, when comparing brain glucose uptake using PET/CT, one should consider the effects of anesthetic protocols on different regions of the glucose uptake in the dog's brain.