Effects of Glucose Concentration on in vitro Fertilization in BALB/c Mice

BALB/c mice are widely used in genetic, tumour and immunological studies. However, the mice demonstrate a lower reproduction rate, low fertility and small litters, because of their highly genetic homozygoisty. Based on in vitro fertilization (IVF), a routine technique for biomedical studies, it is worth to evaluate the effects to BALB/c mice on IVF efficiency. In order to test the genetic factor affecting the IVF efficiency of BALB/c, four reciprocal IVF tests of BALB/cByJ and FVB/NCrl mice were performed. The results showed that the average fertility of IVF sponsored by FVB/NCrl spermatozoa was 69.6%, but only 12.1% was obtained from BALB/cByJ strain. Effect of glucose contained in the culture medium to the IVF efficiency of BALB/cByJ was also evaluated. The results showed that the fertility of BALB/cByJ spermatozoa incubated with 0, 2.7, 5.5, 11.1 and 22.2 mm of glucose in the TYH medium were 6.8, 9.9, 13.9, 32.7 and 22.2%, respectively. It is showed that IVF efficiency of BALB/cByJ spermatozoa could be improved depending on the concentration of glucose in the IVF medium. According to the results, it is beleived that lower IVF of BALB/cByJ mice might be due to the genetic defect in spermatozoa and increasing glucose in the IVF medium which significantly affect the IVF efficiency of BALB/cByl via activating the spermatozoa.     

The occurrence and antimicrobial susceptibility of salmonellae isolated from commercially available canine raw food diets in three Canadian cities

The purpose of the present study was to evaluate the prevalence and antimicrobial resistance patterns of Salmonella isolated from commercially available canine raw food diets in Canada. A total of 166 commercial frozen raw food diet samples were purchased from randomly selected local pet stores in three Canadian cities for a period of 8 months. All samples were evaluated for the presence of Salmonella, serotyped and tested for antimicrobial susceptibility. There was an overall Salmonella prevalence of 21%; chicken was an ingredient for 67% of the Salmonella-positive diets. Eighteen different Salmonella serotypes were recovered, and resistance was observed to 12 of the 16 antimicrobials tested, with the majority of Ontario isolates exhibiting resistance to ampicillin and Calgary isolates to tetracycline. This study demonstrates the potential risk of raw food diets, especially for immunocompromised individuals, and stresses the need for implementing regulatory guidelines for the production of these diets in order to help control and ideally eliminate the bacterial risks associated with their use and consumption.     

The occurrence and anti-microbial susceptibility of Salmonellae isolated from commercially available pig ear pet treats

In Canada, there have been reported outbreaks of human salmonellosis related to exposure to animal-derived pet treats, involving pig ear treats, beef steak patty dog treats and pet treats of seafood origin. As a follow-up to recommendations made to the pig ear treat industry in 1999, a total of 245 pig ear treats were purchased in two Canadian cities to provide evidence of adoption of the recommendations and to determine the current levels of Salmonella contamination of pig ear treats available at pet stores. An overall prevalence of 4% was observed, with isolates exhibiting resistance to up to seven anti-microbials. Serotypes recovered included S. Bovismorbificans, S. Give, S. Derby and S. Typhimurium var. Copenhagen. Although the prevalence observed during this study is lower than the prevalence observed in 1999, pig ear treats should still be considered as a possible source of Salmonella and anti-microbial resistant bacteria to humans and dogs in Canada.     

Description of recent foot and mouth disease outbreaks in nonendemic areas: exploring the relationship between early detection and epidemic size

The objective of this investigation was to describe the detection of foot and mouth disease (FMD) outbreaks in nonendemic areas, and to consider how events early in an epidemic influence the epidemic's course. We identified 24 epidemics that occurred between 1992 and 2003 in areas officially considered free of FMD. We obtained information about these epidemics from many sources, including the scientific literature, the grey (non peer-reviewed) literature, and individuals involved with the outbreaks. While most of the epidemics consisted of fewer than 150 infected premises, there were 4 extremely large epidemics, each consisting of more than 2000 infected premises. There was no direct relationship between the time to detection and either the total number of infected premises or the number of animals killed for disease control purposes. We believe that the movement of infected animals through markets was the most critical factor that contributed to the unusual magnitude of the very large epidemics.     

Effects of gelatin sponge implantation in cancellous bone defects in dogs

Reports from oral surgeons suggested that packing bone defects with cellulose or collagen stimulated cancellous bone replacement. The study reported here was designed to evaluate a similar method for augmenting the remodeling of cancellous bone defects and graft donor sites. Gelatin sponge was implanted into bony defects created in the proximal humeral metaphysis of 5 adult Beagles after collection of cancellous bone. A similar defect created in the contralateral humerus was left unpacked. Four months after creation of the defect, the dogs were euthanatized, and the surgical sites were evaluated by use of correlated microradiographic and histologic examination. Unpacked sites had filled completely with loosely woven trabecular bone. Remodeling had not taken place in sites packed with gelatin sponge. Gelatin sponge did not elicit any reaction in the surrounding bone, but remained in situ and obstructed new bone formation. Gelatin sponge blocked rather than augmented cancellous bone replacement.     

Investigating the relationship between abomasal hairballs and perforating abomasal ulcers in unweaned beef calves.

This study investigated the relationship between abomasal hairballs (trichobezoars) and perforating abomasal ulcers in unweaned beef calves <4 mo of age. The calves enrolled in the study represented routine necropsy submissions to veterinary practitioners in western Canada and to the Western College of Veterinary Medicine. Regardless of the cause of death, each calf was examined for evidence of abomasal ulcers and hairballs. Thirty-two practitioners and the Western College of Veterinary Medicine provided 166 cases for the study; 56 died of perforating ulcers (ulcer calves), and 110 died of causes unrelated to abomasum (non-ulcer calves). The calves ranged in age from 1-90 d; 154 (92.8%) were <61 d of age. Overall, ulcer calves were 2.74 (P = 0.003) times more likely to die with an abomasal hairball than were the nonulcer calves. However, stratifying the calves into 2 age groups, young (<31 d) and old (>30 d), yielded conflicting results. While the young ulcer calves were 3.81 (P = 0.003) times more likely to have a hairball than were the young nonulcer calves, there was no statistically significant relationship (OR = 0.76, P = 0.65) between ulcer and hairballs in the older calves. The authors concluded that the relationship between hairballs and ulcers in the young calves was probably spurious, created by a Berkson's bias. It is unlikely that abomasal hairballs have a significant role in the development of fatal perforating ulcers in beef calves.     

Developmental Anomalies in Farm Animals: II. Defining Etiology

Anomalous development is a function of the genetic make-up of the fetus and the environment in which it develops. The cause of anomalous development may occasionally be obvious but more often is obscure, because of its multifactorial nature. Therefore a methodological approach is often required to define the etiology. In this paper we describe a methodological approach that first defines the incident, the genotype of the individuals involved, and the environment in which the fetus has developed. This procedure can be undertaken in a stepwise fashion and need not be followed through to the end if the etiology becomes obvious. This approach highlights the necessity to characterize the defects, to use ancillary tests, and to apply basic epidemiological methods.     

Congenital spinal stenosis and dam mortality associated with feeding moldy cereal straw

We describe herein an epidemiological investigation of the cause of a syndrome of congenital spinal stenosis (CSS) in four beef herds in western Canada. Three of the herds were affected with the syndrome in 1987, the fourth was affected in 1990. The prevalence of CSS in affected groups of calves varied from 29% (16/55) to 100% (14/14). All affected calves had congenital posterior paralysis or paresis; some calves also had one or more of the following: shortened limbs, forelimb varus deformities, superior brachygnathia, and a dome-shaped cranium. Affected calves showed focal premature closure of axial and appendicular metaphyseal growth plates. At three of the four farms most of the pregnant cows were affected with alopecia with or without pruritus in January, and 25% of the cows in one herd died during the winter. The investigation indicated that CSS was associated with feeding moldy cereal straw to pregnant beef cows during the winter. At all four farms, the cereal straw bales were thoroughly soaked by rain prior to stacking, and obvious mold was present when they were broken open for feeding. Species of both Penicillium and Fusarium were abundant within the bales. The most likely cause of the disease was a fungal mycotoxicosis, although the mycotoxin responsible was not isolated.     

A field investigation of the economic impact of respiratory disease in feedlot calves

A trial involving 512 beef calves was conducted in a commercial research feedlot to determine the effect of bovine respiratory disease (BRD) on performance parameters and carcass characteristics. Two hundred and fifty-six calves that were deemed to be “sick” (S) from BRD were allocated to 16 pens and 256 calves that were considered to be “well” (W) were allocated to another 16 pens. The outcome variables that were measured included average daily gain (ADG), daily dry matter intake (DDMI), dry matter intake to gain ratio (DM:G), BRD treatment rate, death loss, carcass traits, and net profit per pen.

The data were partitioned into several time intervals including processing (P) to day −1, day 0 to day 27, day 28 to day 55, day 56 to day 83, day 84 to day 111, day 112 to day 139, day 140 to slaughter, day 0 to slaughter (0-Slaugh), and processing to slaughter (P-Slaugh). However, the most important interval was from processing to slaughter.

For the interval P-Slaugh, there were no significant (p≥0.05) differences between the S and W groups with respect to ADG and DM:G. Also, for the interval 0-Slaugh, the DDMI was similar for both groups. There were no significant (p≥0.05) differences between the S and W groups for carcass weight, average fat, grade fat, rib eye area, marbling score, cutability estimate, or carcass grade distribution.

The BRD treatment rates in the S and W groups were 6.6% and 4.7%, respectively. The mortality rates in the S and W groups were 0.78% and 0.39%, respectively. Also, there were no deaths attributable to BRD in either group.

In the economic model, there was no significant (p≥0.05) difference between the S and W groups with respect to net profit per pen.

We conclude that this trial did not validate the concept that BRD impacts performance parameters, because a sufficient disease challenge was not present. However, this study provides several observations that will enhance the experimental design of future studies that attempt to quantify the total economic impact of BRD.

     

Influence of Cysteamine on In Vitro Maturation, In Vitro and In Vivo Fertilization of Equine Oocytes

The effect of cysteamine on in vitro nuclear and cytoplasmic maturation of equine oocytes collected by transvaginal ultrasound guided follicular aspiration was assessed. Oocytes were matured in vitro with (cysteamine group) or without (control group) cysteamine. The nuclear stage after DNA Hoechst staining, penetration rates after two different in vitro fertilization (IVF) techniques (IVF media with ionophore and Hepes buffer with heparin) and the embryo yield following oocyte intra-oviductal transfer were used as a criterion for assessing nuclear and cytoplasmic maturation, respectively. Contrary to the data described in other domestic species, there was no effect of cysteamine on in vitro nuclear maturation, IVF or in vivo embryonic development under our conditions. Ovum pick up yields (52%) and maturation rates (control group: 47% and cysteamine group: 55%) were similar to those previously reported. From 57 oocytes transferred to the oviduct in each group, the number of embryos collected was 10 (17%) in the control group and five in the cysteamine group (9%). Those two percentages were not statistically different (p > 0.05). No effect of IVF technique was seen on the success rate (6%) in each group.