Multivariate characterisation of the phenotypic traits of Djallonke and Sahel sheep in Northern Ghana

The characterisation of the small ruminant populations in developing countries will play a major role in the maintenance of the genetic resources as the basis for future improvement in livestock production. The present study aimed at morphological characterisation of the two main breeds of sheep in Ghana by assessing variation within and between breed populations using principal component and discriminant analyses. The two breeds were the Sahel and the Djallonke sheep of both sexes and of two groups namely, young (1 year old, consisting of 74 animals) and mature sheep (≥2 years old, comprising 219 animals). The analysis of variance revealed significant (P?<?0.05) differences in the morphological traits of the Sahel and the Djallonke sheep breeds with higher values recorded for the former. Sexual dimorphism was in favour of male animals in all the morphological traits examined. Mature animals also had comparative advantage over the young. Two principal components were extracted to discern the structure of the two genetic groups. The most discriminating traits between the two sheep breeds were rump height, height at withers, neck girth and pin-bone width. Mahalanobis distance between the two genetic groups was 5.723 (P?<?0.0001). The developed discriminant functions clearly discriminated and classified the Sahel and the Djallonke sheep into their breeds of origin, thus yielding 100, 93.4 and 90.4 % accurate classification for the rams, ewes and the overall sheep population, respectively. The present approach would greatly help in establishing management and conservation policies for the sustainable production of the two Ghanaian sheep breeds.     

Multivariate analysis of sexual size dimorphism in local turkeys (Meleagris gallopavo) in Nigeria

Sexual size dimorphism is a key evolutionary feature that can lead to important biological insights. To improve methods of sexing live birds in the field, we assessed sexual size dimorphism in Nigerian local turkeys (Meleagris gallopavo) using multivariate techniques. Measurements were taken on 125 twenty-week-old birds reared under the intensive management system. The body parameters measured were body weight, body length, breast girth, thigh length, shank length, keel length, wing length and wing span. Univariate analysis revealed that toms (males) had significantly (P < 0.05) higher mean values than hens (females) in all the measured traits. Positive phenotypic correlations between body weight and body measurements ranged from 0.445 to 0.821 in toms and 0.053–0.660 in hens, respectively. Three principal components (PC1, PC2 and PC3) were extracted in toms, each accounting for 63.70%, 19.42% and 5.72% of the total variance, respectively. However, four principal components (PC1, PC2, PC3 and PC4) were extracted in hens, which explained 54.03%, 15.29%, 11.68% and 6.95%, respectively of the generalised variance. A stepwise discriminant function analysis of the eight morphological traits indicated that body weight, body length, tail length and wing span were the most discriminating variables in separating the sexes. The single discriminant function obtained was able to correctly classify 100% of the birds into their source population. The results obtained from the present study could aid future management decisions, ecological studies and conservation of local turkeys in a developing economy.     

Aspartic Proteinase Members Secreted by the Ruminant Placenta: Specificity of Three Radioimmunoassay Systems for the Measurement of Pregnancy-associated Glycoproteins

Pregnancy‐associated glycoproteins (PAGs) isolated from the placenta of various ruminant species are enzymatically inactive members of the aspartic proteinase family. The measurement of these proteins in the maternal blood can be a good indicator of the presence of a live embryo. As certain aspartic proteinases are present in biological fluids in physiological and pathological conditions at various concentrations, it was necessary to determine the specificity of three radioimmunoassay (RIA) systems currently used for the detection of PAG molecules. Commercially available members of the aspartic proteinase family like pepsinogen, pepsin, chymosin, rennet, cathepsin D and renin were tested in a wide concentration range (10 ng/ml – 1 mg/ml). Pepsinogen cross‐reacted in RIA 1, RIA 2 and RIA 3 over 1 mg/ml, 50 μg/ml and 500 μg/ml concentrations, respectively. In the presence of pepsin, cross‐reaction was observed in RIA 1, RIA 2 and RIA 3 over 1 mg/ml, 500 μg/ml and 1 mg/ml concentrations, respectively. Chymosin and rennet could cross‐react in RIA 2 and RIA 3, while renin and cathepsin D did not decrease the binding of the tracer to antisera more, than that of the minimal detection limit. As the plasma/serum concentrations of the examined aspartic proteinases reported in the literature were outside the concentration range where cross‐reaction was observed, it can be concluded that these RIA systems were specific for the detection of PAGs in biological fluids.     

Factors Affecting Plasma Pregnancy-associated Glycoprotein 1 Concentrations Throughout Gestation in High-producing Dairy Cows

This study was designed to establish the factors, if any, which could affect plasma pregnancy-associated glycoprotein-1 (PAG-1) expression in a study population of 87 pregnant, high-producing dairy cows. The factors examined were: semen providing breed (Holstein-Friesian vs Limousin), outcome of gestation (male vs female newborn, and singleton vs twin pregnancies), lactation number, milk production at pregnancy diagnosis, plasma progesterone concentration, season of gestation (warm period, March–November vs cool period, December–February), and day of gestation (40, 90, 120, 150, 180 and 210). Pregnancy was diagnosed by transrectal ultrasound on day 40 post-insemination and by palpation per rectum on days 90, 120, 150, 180 and 210. Blood samples were collected from each animal immediately before each pregnancy diagnosis. The relative contributions of the different factors on PAG-1 concentrations were evaluated by GLM repeated measures analysis of variance. No significant effects of the herd, foetal sex, milk production, lactation number and plasma progesterone concentrations were observed. In contrast, twin pregnancy, the use of Limousin semen and conception during the cool period were correlated with significantly increased plasma PAG-1 concentrations throughout gestation. Our data indicate that both cow well-being during early placental development, determined in our conditions by reduced heat stress when conception occurred in the cool season, and crossbreed pregnancies lead to improved PAG-1 production throughout the gestation period.     

Tuberculosis in dromedary camels slaughtered in Nigeria: a documentation of lesions at postmortem

Tropical Animal Health and Production - In comparison with other livestock, tuberculosis (TB) in camels has not been extensively studied in Nigeria. Camels in the hands of Nigerian pastoralists...     

Experimental Neospora Caninum Infection in Pregnant Dairy Heifers Raises Concentrations of Pregnancy‐Associated Glycoproteins 1 and 2 in Foetal Fluids

Plasma concentrations of PAG‐1 are used for pregnancy diagnosis and as a marker of placental/foetal well‐being, while those of PAG‐2 may be an indicator of abortion risk in Neospora caninum‐infected cows. Studies have shown that N. caninum infection modifies PAG‐1 and PAG‐2 patterns in maternal blood plasma. However, no prior work has examined the effects of N. caninum infection on concentrations of PAGs in foetal fluids. In this study, PAG‐1, PAG‐2 and pH levels were determined in the amniotic and allantoic fluids of foetuses collected at 152 days of gestation from control uninfected dams and from dams experimentally infected with N. caninum on Day 110 of gestation. Foetal fluids from infected foetuses had significantly higher PAG‐2 concentrations (p = 0.026) and pH values (p = 0.02) than fluids from non‐infected foetuses. In infected foetuses, significantly higher concentrations of PAG‐1 (p < 0.001) and PAG‐2 (p < 0.001) were detected in fluid samples showing antibodies against N. caninum than those without antibodies. Moreover, pH values were significantly higher (p = 0.011) in foetal fluid samples with antibodies than in samples from non‐infected foetuses. In conclusion, this is the first report on the effect of N. caninum infection on PAG levels in foetal fluids. Our results indicate that following the experimental infection of dams with N. caninum on Day 110 of gestation, foetal fluids collected from the infected foetuses of these dams featured higher PAG‐1 and PAG‐2 levels and pH values than fluids from non‐infected controls, provided that the samples tested showed the presence of antibodies. The clinical implications of these findings are that following infection with N. caninum, most cows will experience some level of placental damage and that this injury correlates with foetal fluid PAG levels and pH.     

Biogeochemical evidence for dinoflagellate ancestors in the early cambrian

Dinoflagellates are single-celled organisms that reflect the ecological conditions in modern oceans and lakes. Ultrastructural data and molecular phylogeny suggest that they originated in the Neoproterozoic, yet dinoflagellate ancestors are classified only to the Middle Triassic ( approximately 240 million years ago). Examination of dinoflagellate-specific biological markers (dinosteranes and 4alpha-methyl-24-ethylcholestane) in concentrated microfossils with known morphology identified ancient dinoflagellate ancestors from the Early Cambrian ( approximately 520 million years ago).