Additive genetic relationships between heifer pregnancy and scrotal circumference in Nellore cattle

To estimate heritability (h2) for yearling heifer pregnancy and to estimate the genetic correlation between heifer pregnancy and scrotal circumference, 18,145 records of Nellore heifers exposed to breeding at an age of approximately 14 mo and 25,466 records of contemporary young bulls were analyzed. Heifer pregnancy was considered as a categorical trait, with the value 1 (success) assigned to heifers that were pregnant after rectal palpation approximately 60 d after the end of a 90-d breeding season and the value 0 (failure) otherwise. A single-trait animal model for heifer pregnancy and a two-trait animal model including heifer pregnancy and scrotal circumference were used. Contemporary groups were defined in two ways: including (CG2) or not including (CG1) weaning management of the heifer. Heritability estimates obtained by Method R in single-trait analyses were 0.68 +/- 0.09 and 0.61 +/- 0.10 using CG1 and CG2 definitions, respectively. Heritability estimates for two-trait analyses were 0.69 +/- 0.09 (CG1) and 0.63 +/- 0.08 (CG2) for heifer pregnancy and 0.57 +/- 0.03 (both CG) for scrotal circumference. The genetic correlation estimates between the two traits were 0.20 +/- 0.12 (CG1) and 0.20 +/- 0.13 (CG2). Based on the results of this study, EPD for heifer pregnancy can be used to select bulls for the production of precocious daughters and will be more effective than selecting on scrotal circumference EPD in Nellore cattle. However, scrotal circumference can be incorporated in a two-trait analysis to increase the accuracy of prediction for heifer pregnancy EPD for young bulls. Using contemporary group without heifer weaning management gave higher h2 and, for two-trait analysis, converged more quickly.     

Effect of metoclopramide on gastro-esophageal reflux in anesthetized dogs

Administration of morphine before anesthesia leads to gastro-esophageal reflux (GER) in over 50% of dogs during the subsequent anesthetic. This GER is clinically silent but can lead to aspiration pneumonitis, esophagitis and esophageal stricture. In this prospective clinical study we aimed to determine the effect of metoclopramide on gastro-esophageal reflux (GER) in dogs undergoing elective orthopedic surgery. Dogs were admitted to the study if they were healthy, and had no history of vomiting or dysphagia. Dogs were fasted for an average of 18.2 ± 4.3 (mean ± SD) hours prior to induction of anesthesia. Anesthesia in all dogs included acepromazine, morphine, thiopental and isoflurane in oxygen. By random allocation, half the dogs received metoclopramide (M) as an IV bolus (0.4 mg kg^–1) and then infusion (0.3 mg kg^–1hour^–1), the others received equivalent volumes of saline (S). To measure esophageal pH a sensor-tipped catheter was placed with the tip 5–7 cm cranial to the lower esophageal sphincter, and connected to a computer for continual data collection. The pH of any fluid running from the mouth or nose was measured. Gastro-esophageal reflux was defined as a decrease in esophageal pH below 4 or an increase above 7.5. Fisher's Exact test was used to test significance of differences in incidence between groups. Separate multivariable logistic regression models were created for each outcome to assess the effects of risk factors on outcome. There were seven cases of GER in 16 dogs receiving M and 8/14 in those receiving S. There were no significant differences between M and S treated dogs in age, weight, duration of anesthesia and fasting, thiopental dose or incidence of vomiting. The administration of metoclopramide at this dose did not significantly reduce the incidence of GER in these anesthetized dogs.     

Retrospective analysis of detomidine infusion for standing chemical restraint in 51 horses

Objective To assess the effectiveness of a detomidine infusion technique to provide standing chemical restraint in the horse. Design Retrospective study. Animals Fifty‐one adult horses aged 9.5 ± 6.9 years (range 1–23 years) and weighing 575 ± 290.3 kg. Methods Records of horses presented to our clinic over a 3‐year period in which a detomidine infusion was used to provide standing chemical restraint were reviewed. Information relating to the types of procedure performed, duration of infusion, drug dosages and adjunct drugs administered was retrieved. Results Detomidine was administered as an initial bolus loading dose (mean ± SD) of 7.5 ± 1.87 µg kg^?1. The initial infusion rate was 0.6 µg kg^?1 minute^?1, and this was halved every 15 minutes. The duration of the infusion ranged from 20 to 135 minutes. Twenty horses received additional detomidine or butorphanol during the procedure. All horses undergoing surgery received local anesthesia or epidural analgesia in addition to the detomidine infusion. A wide variety of procedures were performed in these horses. Conclusions Detomidine administered by infusion provides prolonged periods of chemical restraint in standing horses. Supplemental sedatives or analgesics may be needed in horses undergoing surgery. Clinical relevance An effective method that provides prolonged periods of chemical restraint in standing horses is described. The infusion alone did not provide sufficient analgesia for surgery and a significant proportion of animals required supplemental sedatives and analgesics.     

Bayesian Methods for Hierarchical Distance Sampling Models

The few distance sampling studies that use Bayesian methods typically consider only line transect sampling with a half-normal detection function. We present a Bayesian approach to analyse distance sampling data applicable to line and point transects, exact and interval distance data and any detection function possibly including covariates affecting detection probabilities. We use an integrated likelihood which combines the detection and density models. For the latter, densities are related to covariates in a log-linear mixed effect Poisson model which accommodates correlated counts. We use a Metropolis-Hastings algorithm for updating parameters and a reversible jump algorithm to include model selection for both the detection function and density models. The approach is applied to a large-scale experimental design study of northern bobwhite coveys where the interest was to assess the effect of establishing herbaceous buffers around agricultural fields in several states in the US on bird densities. Results were compared with those from an existing maximum likelihood approach that analyses the detection and density models in two stages. Both methods revealed an increase of covey densities on buffered fields. Our approach gave estimates with higher precision even though it does not condition on a known detection function for the density model.     

Intracranial fusariosis: a novel cause of fungal meningoencephalitis in a dog

The Fusarium species are a group of saprophytic fungal organisms that are occasionally the cause of opportunistic infections in humans and animals. Central nervous system disease associated with a Fusarium species is most commonly described in horse, resulting in equine leukoencephalomalacia. This report describes a 2-year-old, spayed, female German Shepherd Dog with meningoencephalitis secondary to infection with Fusarium spp. Meningoencephalitis in dogs secondary to a species of Fusarium has not been previously reported. The diagnosis was made based on the histopathologic examination of brain tissues postmortem and special immunohistochemical stains specific for Fusarium solani. The clinical signs in this dog were indicative of multifocal brain disease and included seizures and a paradoxical vestibular syndrome. The clinical findings, diagnostic and histopathologic test results, and the comparative characterizations of other disseminated fungal diseases, especially aspergillosis, are described.     

Contribution of White Clover Varieties in High-Productivity Systems under Grazing and Cutting

Two medium leaf size varieties of white clover (Trifolium repens L.) were grown in mixture with a range of grass species and varieties in a field experiment conducted over 4 years. The clovers were grown singly or as a blend in swards with a tetraploid perennial ryegrass (Lolium perenne L.), a diploid Italian ryegrass (Lolium multiflorum L.) or tetraploid hybrids between these two species (Lolium x boucheanum Kunth). These grasses were also grown in monoculture. Swards were managed in a regime involving two periods of sheep grazing, two periods of cattle grazing and a silage cut in the same year for 4 years. The objectives of this experiment were 3‐fold: (1) to examine the yield and persistency of white clover in highly productive systems with modern perennial, hybrid and Italian ryegrasses; (2) to compare the performance of white clover varieties grown singly in mixture with grasses with their performance together as a blend, and (3) to examine the persistency of new Italian ryegrass varieties, exemplified by AberComo. The clover content of the sward remained high throughout the experiment, with a mean of 31 % overall. Differences in clover yield between plots were largely attributable to the effects of companion grasses. Total yields were very similar in plots containing different clover varieties and in plots where these varieties had been grown singly or as a blend. Grass yields in mixture were greater than those in monoculture but showed similar relative rankings. The diploid Italian ryegrass variety AberComo showed an unexpectedly high yield in the 4th year of the experiment. The implications of these results for strategies for productive, sustainable agriculture using modern white clover and ryegrass varieties are discussed.     

Enzymatic discoloration and phenolic content of potato tubers from cultivars resistant and susceptible to the golden nematode

Phenolic content and discoloration were determined for 13 commercial potato cultivars and 6 potato clones grown at 2 locations over a period of 5 successive years. Tubers from 6 potato cultivars and 5 potato clones resistant to the golden nematode were compared with tubers from 7 potato cultivars and 1 clone known to be susceptible to the golden nematode. Tubers from resistant plants were lower in phenols and discolored less than tubers from susceptible plants.     

The effects of within-species and between-species variation in wood density on the photodegradation depth profiles of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa)

Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight emitted by a xenon lamp (375 W/m² within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation. The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally, why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural weathering. Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

Resistance to septoria nodorum blotch in the Aegilops tauschii accession RL5271 is controlled by a single gene

Septoria nodorum blotch is the most important leaf disease of wheat in Western Australia. A potentially useful source of resistance has been identified in an accession of Aegilops tauschii. To study the genetics of resistance of this source a cross was made between the resistant Ae. tauschii accession, RL5271, and a susceptible accession, CPI110889. The resistant parent took significantly longer to develop symptoms, developed significantly fewer lesions and expressed significantly lower levels of disease than the susceptible parent. The F1 mean response for disease severity indicated there was no complete dominance. The F3 families were classified using three approaches. In the first approach the individual F3 plant response was used to classify the F3 families. In the second approach the F3 family means and standard errors were used to classify the F3 families. In the final approach Best Linear Unbiased Predictors of disease score and standard error for each F3 family derived from a REML analysis were used to classify the F3 families. The genotypic ratios generated by each of the approaches suggested that resistance is controlled by a single gene. The effectiveness of the resistance and its simple genetic control in the Ae. tauschii, accession RL5271 may be a useful resistance source for use in a bread wheat breeding program. This revised version was published online in July 2006 with corrections to the Cover Date.