Linkage disequilibrium and effective population size in Gir cattle selected for yearling weight

Linkage disequilibrium (LD) plays an important role in genomic selection and mapping of quantitative trait loci (QTL). This study investigated the pattern of LD and effective population size (N_e) in Gir cattle selected for yearling weight. For this purpose, 173 animals with imputed genotypes (from 18 animals genotyped with the Illumina BovineHD BeadChip and 155 animals genotyped with the Bovine LDv4 panel) were analysed. The LD was evaluated at distances of 25–50 kb, 50–100 kb, 100–500 kb and 0.5–1 Mb. The N_e was estimated based on 5 past generations. The r² values (a measure of LD) were, respectively, .35, .29, .18 and .032 for the distances evaluated. The LD estimates decreased with increasing distance of SNP pairs and LD persisted up to a distance of 100 kb (r² = .29). The N_e was greater in generations 4 and 5 (24 and 30 animals, respectively) and declined drastically after the last generation (12 animals). The results showed high levels of LD and low N_e, which were probably due to the loss of genetic variability as a consequence of the structure of the Gir population studied.     

Differences in body temperature, cell viability, and HSP-70 concentrations between Pelibuey and Suffolk sheep under heat stress

Pelibuey and Suffolk sheep were compared as to their capacity to regulate body temperature under environmental hyperthermia by measuring their differences in cellular response to heat stress (HS). In a first experiment, seven Pelibuey and seven Suffolk ewes were kept in a climatic chamber for 6 h daily during 10 days (temperatures within the 18 to 39.5 °C range). As chamber temperature rose, sheep rectal temperature increased in both groups, but to a lesser extent in Pelibuey (0.3 °C) than in Suffolk sheep (0.7 °C) (P?<?0.05). In a second experiment, cellular viability was assessed using cultured blood mononuclear cells from 15 Pelibuey and 15 Suffolk sheep. They were incubated at 37 °C for 24 h (control) or 43 °C for 6 h followed by 18 h at 37 °C (HS). In a third experiment, another blood mononuclear cells culture from eight Pelibuey and eight Suffolk sheep was kept at 37 °C for 15 h; these were subsequently cultured for 6 h at 37 °C (controls) or 43 °C (HS). Next, HSP-70 concentration was determined. HS reduced the percentage of viable cells to a greater extent in Suffolk [37 °C (73.7 %) vs. 43 °C (61.9 %); P?<?0.05] than in Pelibuey sheep [37 °C (74.9 %) vs. 43 °C (66.7 %); P?>?0.05]. HS significantly increased HSP-70 average concentrations for both breeds at 43 °C. A significant effect was observed for the breed by temperature interaction (P?<?0.05) caused by a greater difference between Pelibuey and Suffolk at 43 °C (2.85 vs. 0.53 ng/mL, respectively; P?<?0.05) than at 37 °C (0.05 vs. 0.03 ng/mL, respectively; P?>?0.05). In conclusion, Pelibuey sheep show more effective body temperature regulation under conditions of environmental hyperthermia. Also, cell viability after HS was higher in Pelibuey than in Suffolk, an effect that could be mediated by an HSP-70-related mechanism.     

Reduction and stabilization of hip luxation by the transposition of the ligamentum sacrotuberale in dogs: an in vivo study

OBJECTIVES: To evaluate the effectiveness of transposition of the sacrotuberous ligament (LST) for the treatment of coxofemoral luxation in the dog. STUDY DESIGN: In vivo experimental study. SAMPLE POPULATION: Ten mixed-breed dogs (weighing 12 to 26 kg). METHODS: After general anesthesia, the LST was exposed and released from the sacrum with a sacral bone fragment. Coxofemoral luxation was created by capsulotomy and transection of the ligament of the head of the femur. Suture was passed through 2 small holes in the bone fragment to guide transposition of the LST through a tunnel drilled through the acetabulum and femoral head and neck. The suture material was pulled tight and an interference screw was placed into the femoral tunnel to lock the sacral bone fragment and LST securely in the tunnel. Butorphanol was administered for pain relief and dogs were allowed unrestricted activity. Coxofemoral radiographs were obtained at 15-day intervals. Two dogs were euthanatized for macroscopic and histopathologic examinations at 3 months. RESULTS: Release of the sacral bone was moderately difficult. The transposed ligament and bone fragment were of an appropriate length and were easily and securely fixed by a interference screw method. Visible severe lameness, during the first 7 to 10 days improved to mild lameness within 10 to 21 days. Gait was subjectively normal after 5 weeks. No radiographic abnormalities were observed at any time point. Grossly, the LST was intact and apparently viable and functional. On histopathology, the space in the bone tunnel was filled with new tissue and a hyaline-like layer surrounded the LST. The sacral bone fragment attached to the LST was united with the femoral bone. CONCLUSIONS: Transposition of the LST reduced and stabilized experimentally induced coxofemoral luxation in 10 dogs. Survival of the LST up to 3 months and its adaptation to transposition suggest that this surgical technique could be considered as a permanent treatment option for hip luxations. Transposition and fixation of the LST was easy, but releasing the sacral edge of the LST was difficult because of its deep location and division of the origin into 2 branches in some dogs. CLINICAL RELEVANCE: Results of this experimental study suggest that the technique may be satisfactorily used in dogs with coxofemoral luxation.     

Squamous cell carcinoma of the footpad with systemic metastasis in a captive crowned solitary eagle (Buteogallus coronatus)

Squamous cell carcinomas (SCC) are one of the most common tumors of the tegument that can have a misdiagnosis of chronic skin wounds. An adult captive crowned solitary eagle presented an indolent wound-like ulcer on the footpad and a fatal outcome. An infiltrating tumoral mass in the foot and multiple tumoral metastatic nodules in visceral organs were detected. The neoplasm was composed of atypical squamous cells with strong positivity for cytokeratin, “keratin pearl” structures, and marked invasion of tissues confirming a diagnosis of metastatic SCC. This might be the first report of an SSC with metastasis on the footpad in a captive Chaco eagle, which is one of the endangered species of birds of prey.     

Adenosine deaminase activity in serum, erythrocytes and lymphocytes of rats infected with Leptospira icterohaemorrhagiae

Leptospirosis is a systemic disease of humans and domestic animals, mainly dogs, cattle and swine. The course of human leptospirosis varies from mild to severe fatal forms and the most severe form of human leptospirosis is principally caused by Leptospira interrogans serovar icterohaemorrhagiae (L. icterohaemorrhagiae). The enzyme adenosine deaminase (ADA) plays an important role in the production and differentiation of blood cells. The aim of this study was to evaluate the activity of ADA in serum, erythrocytes and lymphocytes of rats infected with L. icterohaemorrhagiae, as compared with non-infected rats. Twenty-four adult rats, divided into two uniform groups (A and B) were used for the enzymatic assays. The animals in Group B were inoculated intraperitoneally with 2×10(8) leptospires/rat, and the rodents in Group A (control) were not-inoculated. Blood collection was performed on days 5 and 15 post-infection (PI) and the blood used to assess the ADA activity. The infection by L.icterohaemorrhagiae altered erythrocyte count, hemoglobin concentration and hematocrit, causing a decrease in all these parameters on day 15 PI. Lymphocytes decreased significantly on day 15 PI, and ADA activity in serum was inhibited in infected rats on days 5 and 15 PI and its activity in erythrocytes were increased on day 5 PI. On day 5 PI, we found an increase in ADA activity in erythrocytes of infected rats. No correlation was observed between hematocrit and erythrocyte ADA activity on days 5 and 15 PI. The ADA activity was inhibited in rats infected on day 15 PI. A positive correlation (r(2)=60) was also observed between the number of lymphocytes and ADA activity in lymphocytes on day 15 PI (P<0.05). In conclusion, our results showed that the ADA activity is altered in serum, lymphocytes and erythrocytes in experimental infection by L.icterohaemorrhagiae in rats, concomitantly with hematological parameters.     

Evaluation of the effectiveness of Duddingtonia flagrans and Monacrosporium thaumasium in the biological control of gastrointestinal nematodes in female bovines bred in the semiarid region

Brazil has a herd of 212 million cattle and 171 million hectares of pastures that produce approximately 96 % of Brazilian beef. The Brazilian production system enables animal infection by endoparasites, which are considered one of the main obstacles for the development of this industry and are responsible for considerable economic losses. The control of parasitic diseases is performed via the administration of antiparasitic drugs, but they leave residues of the products in the treated animal, affect non-target organisms and select resistant strains of the parasites. The species D. flagrans and M. thaumasium are promising and sustainable alternatives for controlling gastrointestinal helminths of ruminants and other herbivores. In this study, we evaluated the efficacy of isolates of these species, formulated in a sodium alginate matrix and administered twice a week, to reduce the number of environmental infective larvae of gastrointestinal nematodes that affect prepubescent zebu females. The treated animals presented fewer eggs and a lower number of infective larvae per gram of faeces (p?<?0.05). The pastures occupied by treated animals showed a statistically significant reduction (p?<?0.05) of the number of L₃ and, furthermore, the genera Cooperia sp., Haemonchus sp., and Oesophagostomum sp. were the most prevalent. The average weight of the animals did not differ statistically (p?>?0.05) among the treated and control groups. The use of sodium alginate pellets as vehicle for delivery of the fungus mycelia D. flagrans (isolate AC001) and M. thaumasium (isolate NF34A) proved effective in controlling trichostrongylids in prepubescent cows bred in the semi-arid region, with an effective reduction in the number of infective larvae in the pastures.