Spermatic and oxidative profile of domestic cat (Felis catus) epididymal sperm subjected to different cooling times (24, 48 and 72 hours)

Cooling stored epididymal samples for several days allows facilities to transport and process genetic material post‐mortem. Improvements to this practice allow the preservation of sperm from domestic cats, which are the ideal study model for wild felids. However, the modifications in spermatic features and the oxidative profile are not fully understood in cats. This information is necessary for the development of biotechniques, such as new extenders for cryopreservation. Therefore, the purpose of this study was to evaluate the spermatic and oxidative profile in samples from the epididymal cauda of domestic cats cooled at 5°C for 24, 48 and 72 hr. Spermatozoa were collected from the epididymis cauda. Evaluations consisted of computer‐assisted sperm analysis (CASA), plasma membrane integrity (eosin/nigrosin), acrosome integrity (fast green/rose bengal), sperm morphology, sperm DNA integrity (toluidine blue), mitochondrial activity (3′3 diaminobenzidine), activity of the antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), measurement of lipid peroxidation (TBARS) and protein oxidation. A decrease in sperm motility parameters was observed after 72 hr of cooling (i.e. total and progressive) with a higher percentage of minor (37.7 ± 6.3%) and total defects (53.4 ± 6.3%). Additionally, a decrease in high mitochondrial activity (Class I: 16.6 ± 2.2%) occurred after 72 hr. The decrease in motility rates after a long cooling time probably was caused by the increase in sperm abnormalities. A long cooling time causes cold shock and mitochondrial exhaustion, but there was no observed change with the oxidative stress condition. Therefore, cat epididymal sperm stored at 5°C appear to maintain a high quality for up to 48 hr of cooling time.     

A fast,low‐cost and efficient method for the diagnosis of sperm DNA fragmentation in several species

Sperm DNA fragmentation is a condition that interferes directly in the reproductive efficiency. Currently, there are several methods for assessing the sperm DNA integrity, such as Alkaline Comet, TUNEL and Sperm Chromatin Structure Assay. However, many of these techniques are laborious and require high‐precision equipment. Thus, the development of new techniques can optimize the evaluation of sperm DNA damage. Therefore, the aim of this study was to standardize the toluidine blue (TB) stain technique for the analysis of DNA fragmentation of dog, cat, bull, stallion and ram spermatozoa. For this purpose, we used six animals of each specie (n = 30), in reproductive age. Sperm was collected by different methods according to the particularities of each species, and such samples were divided into two aliquots: a sperm sample was kept at 5°C (considered as intact sperm DNA), and the remaining samples were submitted to the induction of DNA fragmentation by exposure to ultraviolet light for 4 hr. Samples were then mixed with the intact sample to obtain known and progressive proportions of sperm with fragmented DNA (0%, 25%, 50%, 75% and 100%). Semen smears were performed and subjected to staining with TB. Blue‐stained spermatozoa were considered to have DNA fragmentation. We observed high linear regression coefficients between the expected proportion of damaged DNA and the results of TB for dog, cat, ram, bull and stallion samples. In conclusion, TB stain was considered a fast and effective technique for the study of spermatozoa DNA in several species.     

Equine conidiobolomycosis: A review and case study

Conidiobolus coronatus is one of the most commonly identified upper respiratory fungal pathogens in horses. This article includes a review of clinical signs, diagnostics, treatment and outcomes in previously reported cases of equine conidiobolomycosis, as well as six additional cases seen at our hospital. Each of the six horses presented with a complaint of serosanguinous or haemorrhagic nasal discharge and conidiobolomycosis was confirmed by histopathology and fungal culture. Five horses recovered after administration of antifungal drugs alone (n = 4) or in combination with extensive nasal septum resection (n = 1). Surgical treatment alone was ineffective. One horse was euthanised without treatment because of the extent of the disease.     

Impact of a sustained-release ivermectin bolus on weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Québec.

This field trial was designed to test the effect of treatment with a sustained-release ivermectin bolus on average daily and total weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Quebec. One hundred and twelve heifers from 12 herds were randomly assigned at turnout either to treatment with a commercially-available ivermectin bolus or to remain as untreated controls. Ninety-six heifers, 49 treated animals and 47 controls, completed the trial. Animals were weighed at turnout, midseason, and at the end of the grazing season. Fecal samples were collected at each of these times and nematode eggs counted. Nematode egg excretion was relatively low throughout the pasture season, which was abnormally warm and dry until midsummer. Over the entire pasture season, average daily weight gain was higher in treated than in control animals (difference = 0.08 kg/day, P = 0.010). Total weight gain was also higher in treated animals than in control animals (difference = 12.82 kg, P = 0.013). The results of this study suggest that preventive treatment of breeding age, grazing dairy heifers with a sustained-release ivermectin bolus provides a significant weight gain advantage, in situations with moderate utilization of moderately contaminated pastures.     

Kisspeptin,c‐Fos and CRFR Type 2 Co‐expression in the Hypothalamus after Insulin‐Induced Hypoglycaemia

Normal reproductive function is dependent upon availability of glucose and insulin‐induced hypoglycaemia is a metabolic stressor known to disrupt the ovine oestrous cycle. We have recently shown that IIH has the ability to delay the LH surge of intact ewes. In the present study, we examined brain tissue to determine: (i) which hypothalamic regions are activated with respect to IIH and (ii) the effect of IIH on kisspeptin cell activation and CRFR type 2 immunoreactivity, all of which may be involved in disruptive mechanisms. Follicular phases were synchronized with progesterone vaginal pessaries and at 28 h after progesterone withdrawal (PW), animals received saline (n = 6) or insulin (4 IU/kg; n = 5) and were subsequently killed at 31 h after PW (i.e., 3 h after insulin administration). Peripheral hormone concentrations were evaluated, and hypothalamic sections were immunostained for either kisspeptin and c‐Fos (a marker of neuronal activation) or CRFR type 2. Within 3 h of treatment, cortisol concentrations had increased whereas plasma oestradiol concentrations decreased in peripheral plasma (p < 0.05 for both). In the arcuate nucleus (ARC), insulin‐treated ewes had an increased expression of c‐Fos. Furthermore, the percentage of kisspeptin cells co‐expressing c‐Fos increased in the ARC (from 11 to 51%; p < 0.05), but there was no change in the medial pre‐optic area (mPOA; 14 vs 19%). CRFR type 2 expression in the lower part of the ARC and the median eminence was not altered by insulin treatment. Thus, disruption of the LH surge after IIH in the follicular phase is not associated with decreased kisspeptin cell activation or an increase in CRFR type 2 in the ARC but may involve other cell types located in the ARC nucleus which are activated in response to IIH.     

DISTAL BORDER FRAGMENTS OF THE EQUINE NAVICULAR BONE: ASSOCIATION BETWEEN MAGNETIC RESONANCE IMAGING CHARACTERISTICS AND CLINICAL LAMENESS

Distal border fragments of the navicular bone are increasingly being detected due to the improved capabilities of magnetic resonance imaging (MRI), but their clinical significance remains unclear. The purpose of this retrospective study was to describe the location, size, and frequency of fragments in a cohort of horses presented for MRI of the foot and to compare MRI findings with severity of lameness. Archived MRI studies and medical records were searched from March 2006 to June 2008. Horses were included if a distal border fragment of the navicular bone was visible in MRI scans. Confidence interval comparisons and linear regression analyses were used to test hypotheses that fragments were associated with lameness and lameness severity was positively correlated with fragment volume and biaxial location. A total of 453 horses (874 limbs) were included. Fragments were identified in 60 horses (13.25%) and 90 limbs (10.3%). Fifty percent of the horses had unilateral fragments and 50% had bilateral fragments. Fragments were located at the lateral (62.2%), medial (8.89%), or medial and lateral (28.9%) angles of the distal border of the navicular bone. There was no increased probability of being categorized as lame if a fragment was present. There was no significant difference in fragment volume across lameness severity categorizations. Confidence intervals indicated a slightly increased probability of being classified as lame if both medial and lateral fragments were present. Findings indicated that distal border fragments of the navicular bone in equine MRI studies are unlikely to be related to existing lameness.     

Effect of the seaweed Ascophyllum nodosum on lambs during forced walking and transport

The objective of this study was to determine the effect of feeding Ascophyllum nodosum (ANOD) to lambs at 0 (control), 0.5, 1, or 2% of DMI/d for 2 wk on lamb physiology in response to forced walking and transport during hot weather. Forty-four lambs (26 kg +/- 4.3) were used, and each lamb swallowed 3 gelatin capsules filled with ANOD or their normal 16% CP, pelleted grain ration twice daily, with the amount of ANOD dependent on the treatment. The amount of ANOD did not affect ear canal temperature or cortisol concentrations during 60 min of forced walking. The range between the minimum and maximum ear canal temperature for each lamb during 12 h of transport was narrower in lambs receiving the 2% ANOD than the control group (P = 0.05), and the 2% ANOD group also had lower (P = 0.05) ear canal temperatures than the control group during hot periods of transport. After 4 (P = 0.09) and 8 h (P = 0.05) of transport, the control group tended to have greater cortisol concentrations than the 2% ANOD group. Many differences among treatments were found in plasma protein, albumin, calcium, phosphorus, glucose, blood urea nitrogen, aspartate aminotransferase, magnesium, sodium, potassium, and chloride concentrations posttransport; mainly, the control and 0.5% ANOD groups had greater (P < 0.05) concentrations than the other 2 treatments. Aldosterone concentrations were greater in the control and 0.5% ANOD group than in the 1 and 2% ANOD groups before transport, whereas the concentrations were not different after transport, suggesting pretransport concentrations were lowered by supplementation. The 1 and 2% ANOD groups lost more BW than the control group as a result of transport (P = 0.04). After transport, no differences were observed in the latency for lambs to drink, eat, or lay. There was a suppression of the IgG and IgM antibody responses at 4 and 7 d after administration of ovalbumin, with greater ANOD supplementation rates suppressing antibody response the greatest. Although ANOD decreased ear canal temperature in hot periods of transport, stabilized electrolyte concentrations, and decreased cortisol throughout transport, it also suppressed the antibody response indicating that the effect of ANOD on immune function merits further investigation.     

Effect of temperature, elevated carbon dioxide, and drought during seed development on the isoflavone content of dwarf soybean [Glycine max (L.) Merrill] grown in controlled environments

The effects of elevated temperature, carbon dioxide, and water stress on the isoflavone content of seed from a dwarf soybean line [Glycine max (L.) Merrill] were determined, using controlled environment chambers. Increasing the temperature from 18 degrees C during seed development to 23 degrees C decreased total isoflavone content by about 65%. A further 5 degrees C increase to 28 degrees C decreased the total isoflavone content by about 90%. Combining treatments at elevated temperature with elevated CO(2) (700 ppm) and water stress to determine the possible consequences of global climate change on soybean seed isoflavone content indicated that elevated CO(2) at elevated temperatures could partially reverse the effects of temperature on soybean seed isoflavone content. The addition of drought stress to plants grown at 23 degrees C and elevated CO(2) returned the total isoflavone levels to the control values obtained at 18 degrees C and 400 ppm CO(2). The promotive effects of drought and elevated CO(2) at 23 degrees C on the 6' '-O-malonygenistin and genistin levels were additive. The individual isoflavones often had different responses to the various growth conditions during seed maturation, modifying the proportions of the principal isoflavones. Therefore, subtle changes in certain environmental factors may change the isoflavone content of commercially grown soybean, altering the nutritional values of soy products.