Progress in breeding interspecific hybrid ryegrasses

Stable hybrids were produced between tetraploid perennial and Italian ryegrasses derived from commercial varieties and germplasm introduced from European collections. Spaced plant characteristics were used to select Fl plants for the production of F2 families which were assessed in small plots for growth and quality traits. Ten of the 19 selected hybrid families were based on perennial ryegrass collected from the Zurich Uplands. The influence of this parental material in improving vegetative growth during early spring, late summer and autumn was demonstrated. Its use in improving feeding value by increasing the water-soluble carbohydrate content of hybrids was also shown. Consequently, selected hybrid varieties based on this new genetic resource showed considerable improvements in seasonal growth and quality over the older hybrid variety Augusta and Italian ryegrass variety RvP.     

Binding characteristics of swine erythrocyte insulin receptors

Crossbred gilts (controls; n = 7) had 8.8 +/- 1.1% (mean +/- SEM) maximum binding of [125I]insulin to insulin receptors on erythrocytes. The number of insulin-binding sites per cell was 137 +/- 19, with a binding affinity ranging from 7.4 X 10(7)M-1 to 11.2 X 10(7)M-1 and mean of 8.8 X 10(7)M-1. Pregnant sows (n = 5) had a significant increase (P less than 0.01) in maximum binding due to an increase in number of receptor sites per cell. Lactating sows fed a high-fiber diet (n = 3) and a low-fiber diet (n = 4) did not develop a significant difference in maximum binding of insulin. Sows fed the low-fiber diet had a significantly higher number of binding sites and a significantly lower binding affinity than did sows fed a high-fiber diet. Receptor-binding affinity was lower in the low-fiber diet group than in cycling gilts, whereas data from sows fed the high-fiber diet did not differ from data for cycling gilts. Data from this study indicated that insulin receptors of swine erythrocytes have binding characteristics similar to those in other species. Pregnancy and diet will alter insulin receptor binding in swine.     

Concentration and prevalence of Escherichia coli O157 and Salmonella serotypes in sheep during slaughter at two Australian abattoirs

Objective This study aimed to determine the presence and concentration of Escherichia coli O157 and Salmonella spp. on fleece, faeces and carcases of sheep during slaughter. Procedure Faeces, fleece and pre-chill carcase samples were collected from 164 sheep slaughtered at two Australian abattoirs. The presence of E. coli O157 and Salmonella spp. were determined by use of automated immunomagnetic separation (AIMS) with enumeration by use of the ‘most probable number’ (MPN) method. Results Escherichia coli O157 was isolated from 5% of faeces, 3% of fleeces and 0.6% of pre-chill carcases. The mean log₁₀ count of E. coli O157 positive faecal samples was 2.32 MPN/g, but counts on fleeces and carcases were below the countable limit (−1 log₁₀ MPN/cm²). Salmonella spp. were isolated from 20% of faeces, 13% of fleeces and 1.3% of pre-chill carcases. The mean log₁₀ count of Salmonella spp. in faeces was 1.43 MPN/g and on fleece was −0.24 MPN/cm², but counts on carcases were below the countable limit (−1 log₁₀ MPN/cm²). Conclusion The prevalence and concentration of pathogens were low in the sheep tested in this study, indicating a low risk of human infection from products derived from these animals.     

规模化猪场猪支原体肺炎控制及净化技术研究

在四川蒲江某规模化８养猪场 ,对该场的猪支原体肺炎采用以监测、免疫为主,隔离、治 疗、淘汰、消毒等综合防制技术进行控制与净化,对全场有猪支原体肺炎症状的猪及可疑病猪进行隔治疗,治愈后的猪经与易感猪同居感染不发病,分离猪肺炎支原体为阴性,试验表明治愈后的猪不带菌。对全场种猪和后备健康猪群进行猪支原体肺炎疫苗的免疫接种,经抗体监测和攻毒试验,免疫后２４０天猪支原体肺炎的ＩＨＡ抗体仍可达到１：１０,保护率     

Effect of body condition score and reuse of progesterone‐releasing intravaginal devices on conception rate following timed artificial insemination in Nelore cows

This study had the aim of investigating the efficiency of timed artificial insemination (TAI) through the progesterone‐releasing intravaginal device (PRID), used in new condition and for the second and third times in Nelore cows. The effects of device reuse and body condition score (BCS) on the conception rate (CR) were evaluated in 1,122 multiparous Nelore cows (mean BCS of 2.7 ± 0.4), which were randomly distributed into three groups that received new (n = 330), once (n = 439) and twice used (n = 353) PRID. Among the 1,122 females that underwent TAI, 573 became pregnant, thus representing an overall CR of 51.06%. Cows with BCS between 2.75 and 4.0 had greater (p < .0001) CR (69.75%) than cows with BSC of 2.0–2.5 (32.98%). It was observed that the CR through using PRID was 60.00%, 51.71% and 41.93% for new, once and twice used PRID, respectively, with difference between all groups (p < .0001). Under tropical conditions, animals with BCS greater than 2.5 had a higher CR, and the CR decreased proportionally with the number of times that the PRID had been used.     

The influence of haemocyte number on the resistance of the freshwater crayfish, Pacifastacus leniusculus Dana, to the parasitic fungus Aphanomyces astaci

Abstract. The number of circulating haemocytes in crayfish, Pacifastacus leniusculus Dana, was reduced after injection of yeast cell walls (Zymosan) into the animals. Crayfish harbouring the parasitic fungus A. astaci as a 'latent' infection in melanized areas in the cuticle died due to unrestricted growth of unmelanized hyphae when they were injected with Zymosan. The β–1,3–gIucan laminaran, introduced into the haemocoel of P. leniusculus harbouring A. astaci hyphae in the cuticle, also caused a decrease in the total haemocyte counts (THC), but these animals survived the treatment and no unmelanized hyphae of A, astaci were found. The recovery of THC was found to be more rapid after laminaran injection than after Zymosan injection, which could explain why laminaran treated crayfish retained their resistance and could combat the A. astaci hyphae in the cuticle. The importance of the number of haemocytes in defence and well-being of crayfish is discussed.     

Work conditions, job preparation, and placement strategies for food-animal veterinarians

This study examines the responses of 1,047 human-resources personnel who recruit veterinarians for positions in their organizations. Work conditions in the organization, lifestyle and time-management issues, job benefits, job expectations, supervisor relations, and the physical demands of veterinary work are studied. Comparisons are made between four different occupational areas: food animals, mixed animals, companion animals, and industry positions in veterinary medicine. The findings portray a career in food animal medicine as very positive. Recruiters also make recommendations to colleges of veterinary medicine for strategies to improve the preparation and placement of their graduates.     

Morpho-molecular identification of Heterophyes heterophyes encysted metacercariae and its immunological and histopathological effects on farmed Mugil cephalus in Egypt

Aquaculture International - Molecular and immunological aspects of heterophyid infections in mullets are scanty. This study was initiated to identify heterophyid encysted metacercariae infecting...