Assessment of Sperm DNA Fragmentation in Stallion (Equus caballus) and Donkey (Equus asinus) Using the Sperm Chromatin Dispersion Test

Sperm DNA fragmentation (sDF) is an important parameter to assessing sperm quality. Information about sperm quality is not available for donkeys, especially in some breeds at risk of extinction. The objectives of this research were to test the four commercial variants of sperm chromatin dispersion test (SCD; sperm Halomax test), originally developed to assess sDF in boars, bulls, rams and stallions, in order to scrutinize their applicability in the study of sDF in a donkey breed at risk of extinction (Zamorano-Leonesa), for which there is no specific test available to analyze sperm at present. Only the SCD test, originally developed for stallions, produced stable and consistent results, and was deemed suitable to assess DNA fragmentation in sperm samples from donkeys. Image analysis was used to compare differences between the SCD methodology applied to stallion and donkey semen samples processed under the same experimental conditions. The extent of SCD in the SCD test was approximately 20% lower in donkey sperm than in stallion sperm. Yet, the ratio of chromatin sperm dispersion achieved in fragmented and unfragmented nuclei did not differ significantly between species. These data suggest that a similar protein depletion treatment can cause differences in protein removal in equivalent cells from different species and that sperm chromatin may be organized differently in stallions and donkeys.     

Blood culture status in mature horses with diarrhoea: A possible association with survival

Reasons for performing study: The incidence and implications of positive blood cultures in mature horses with diarrhoea is unknown. The diagnosis of bacteraemia may alter treatment and prognosis. Hypothesis: The proportion of horses with diarrhoea that are blood culture positive is higher than previously assumed and a positive blood culture has a negative impact on survival. Methods: Blood cultures were taken at admission and 24 h after admission from 31 mature horses with diarrhoea. Results: Nine (29%) horses were blood culture positive within 24 h of admission. Organisms isolated included Corynebacterium spp. (n = 6), Streptococcus spp. (n = 2), Pantoea agglomerans (n = 1), Gram‐negative rod (n = 1), Bacillus spp. (n = 1) and yeast (n = 1). Horses with positive blood cultures were significantly less likely to survive. Prior treatment with antimicrobial drugs had no significant effect on blood culture status. Horses with positive blood cultures had a significantly higher heart rate, packed cell volume (PCV) and plasma potassium concentration at admission, and a higher PCV and lower total plasma protein concentration 24 h after admission. Conclusions: Positive blood cultures occur more frequently than previously reported, and may have a negative impact on survival in horses with diarrhoea. Potential relevance: Results of blood cultures may be useful in formulating a prognosis for horses with diarrhoea. Further research is required to determine the effect of antimicrobial treatment on outcome.     

Opportunities for reducing the environmental impact of dairy farming managements: a systems approach

Dairy farming systems are important sources for the emission of a number of materials that include various forms of nitrogen (NO₃⁻, N₂O and NH₃) with potential environmental impact. The present paper is a systems synthesis study and assesses the likely impact of changes in management on N flows and losses. These include tactical fertilizer adjustment, slurry injection, maize silage production and the use of white clover as an alternative to fertilizer N. Implications for greenhouse gases (N₂O and CH₄) and support energy have also been considered. Substantial reductions in inputs and total and proportional losses by all die options considered were predicted by this study. Thus, using a tactical approach to fertilizer application and injecting slurry or using 50% maize silage reduced overall N losses from 160 (under conventional management) to 86 and 109kg Nha⁻¹ respectively. Combining both possibilities reduced losses further to 69 kg ha⁻¹. Although use of white clover, especially at low contents in the sward, was the most effective regime to reduce losses, this was at some cost to production so that losses per livestock unit (LU) did not always differ from those under other managements. Changing the N management had consequences for greenhouse gas emission with an estimated maximum 70% reduction in N₂O release. The effects on CH₄ emissions were relatively small. Substantial reductions in support energy costs were also obtained: these arose mainly from the reduction in fertilizer N use, which represented 66% of the total support energy in the original system.     

Production losses in Merino ewes and financial penalties caused by trichostrongylid infections during winter and spring

SUMMARY: The productivity of Merino ewes treated with ivermectin and a controlled-release capsule containing albendazole was compared with untreated ewes grazing the same pastures on each of 3 farms. Treated breeding ewes had significantly increased greasy fleece weights (GFW, 6.5% and 7.1%) compared with untreated breeding ewes, on 2 of 3 farms but treatment caused no significant increase in the GFW of non-breeding ewes. Other benefits of treatment on all farms were a significant increase in body weight gain (from 1.7 to 3.7 kg) and a significant decrease in the weight of dag removed at crutching (from 42 to 622 g). These benefits occurred despite the presence on each farm of worms resistant to benzimidazoles. One disadvantage of treatment was an increase in mean fibre diameter of wool from treated ewes of from 0.12 to 0.41 μm. This increase reduces the value of the wool. Partial budgets indicated a net loss of from 8 to 62 cents per ewe for treatment. However, potential benefits such as increased growth rate and wool production from lambs of treated ewes were not included in the analysis. On one farm ewes were classified as ‘susceptible’ to severe dag if they had a dag score ≥ 4 at the time of capsule treatment. Ewes classified as ‘susceptible’ were about 7 times more likely to develop severe dag than were other ewes. There was no significant difference between the GFW of untreated ‘susceptible’ ewes and untreated ewes not classified as ‘susceptible’. Additionally, the response of GFW to treatment was no different to the response seen in ewes that were not classified as ‘susceptible’. The direct cost of diarrhoea and dag formation in Merino ewes was estimated to be 18, 30, 53, 86, 98 and 145 cents per head for ewes with a dag score of 0, 1, 2, 3, 4 and 5, respectively. This cost did not include potential benefits from reduced risk of breech strike, or intangible benefits associated with the improved welfare of sheep.     

Effect of azaperone on cardiovascular responsiveness in stress-sensitive pigs

The effect of intramuscular azaperone on the cardiovascular responses to stimulation of the sympathetic nervous system was examined in thiopentone-anaesthetized stress-sensitive pigs. Sympathetic stimulation was achieved with the Valsalva-like manoeuvre, and the intravenous tyramine, isoprenaline and phenylephrine tests. The responses were monitored as the changes in heart rate and blood pressure. Azaperone exerted an alpha adrenergic blocking action and possibly a mild beta adrenergic blocking effect. It also retarded pre-adrenoreceptor activation of heart rate. It is suggested that azaperone has peripheral actions which could contribute towards its prophylactic effect in preventing stress-induced deaths in pigs.     

Studies on the biology of black mould (Aspergillus niger) on temperate and tropical onions. 2. The effect of treatments on the control of seedborne A. niger

Treatment of A. niger -inoculated onion seed with benomyl dust (1 g a.i./kg), or a foliar spray of thiram (0·4% a.i./ha) applied to plants grown from inoculated seed under temperate (UK) conditions reduced the incidence of A. niger in harvested crops. Treatment of naturally contaminated Sudanese onion seed with a benomyl + thiram mixture at a rate of 2·5 + 2·5 g a.i./kg or soaking the seed in hot water (15 min at 60°C) reduced the incidence of black mould on bulbs grown in the Sudan in field soil that had not previously been used for onion production. The seed treatments were less effective in crops produced in fields regularly used for onion production. However, incubation of harvested bulbs in moist chambers showed that damage to the internal storage tissue of onion bulbs caused by A. niger was reduced by seed treatment.     

Carcase and meat quality in ducks killed with either gas mixtures or an electric current under commercial processing conditions

1. The feasibility of killing 7-week old Peking ducks with gas mixtures and their effects on carcase and meat quality were evaluated and compared with killing in electrical waterbath under commercial conditions. 2. The prevalence of carcase appearance defects and broken bones in the carcases and haemorrhaging, pH, colour, cooking loss and texture of breast muscles were determined. 3. Ducks can be killed within 3 min by exposure to either 90% argon in air or a mixture of 30% carbon dioxide and 60% argon in air. 4. Gas or controlled-atmosphere killing of ducks, whilst they are still in their transport containers, would eliminate some of the welfare concerns associated with the conventional electrical waterbath stunning systems, without adversely affecting carcase and meat quality.