West Africa Dwarf sheep management systems and exposure to potential stressors in the savannah agroecological zone of Ghana

This study was conducted in the savannah agroecological zone of Ghana to assess the different sheep management systems and identify potential stressors that compromise sheep productivity under these systems. A questionnaire and on-farm observations were used to obtain data from 176 farms on management system types, resources, husbandry practices and productivity. Four management systems were identified in the study area, namely extensive (41.5%), semi-intensive (38.1%), intensive (6.3%) and tethering (14.2%). Feeding systems used were free grazing/scavenging (24.43%), herded grazing (17.05%), zero-grazing/intensive feeding (6.25%), grazing plus supplementation (38.07%) and restricted grazing in the rainy season (14.2%). Most (87%) farmers under the extensive system did not house their sheep at all, but 88.1% of farmers using the semi-intensive system housed their sheep year round. Floor spacing per sheep was 1.06, 2.31, 2.17 and 1.47 sheep/m2 for the intensive, semi-intensive, extensive, and tethering, respectively. Preweaning mortality was significantly higher (40%) than post-weaning to yearling (34.9%) and adult mortality rates (14.3%) (ꭓ2 = 292, P <0.001). The extensive system has the highest (32.8%) mortality rate and the intensive system the least (14.9%) (ꭓ2 = 151, P <0.001). Reproductive indices (lambing percentage, age at first lambing, lambing intervals, and abortion rates) were all significantly influenced by the management system, with sheep managed under the semi-intensive and intensive systems performing better than sheep managed under the extensive system and tethering. Extensive management and tethering of sheep may expose Djallonké sheep to disease stress, chronic undernutrition, heat stress and walking stress compared to sheep under more intensive systems

Postembryonic developmental changes in ovarian histology and associated 17β-oestradiol and progesterone profiles in guinea hens (Numida meleagris)

There is a paucity of information on the reproductive biology of guinea hens. A study was conducted to document postembryonic developmental changes in the ovarian histology and associated progesterone and 17β-oestradiol profiles until 32 weeks of age (WOA). Highly significant increases (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Post-hatch changes in the histological structure of the oviduct and associated 17β-estradiol profiles in guinea hens (Numida meleagris)

There is a limited data available on the biology of guinea fowls. The objective of this study was to document post-hatch histological and stereological changes in the oviducts of 56 guinea hens and associated 17β-estradiol profiles until 32 wk of age and to explore changes in the oviducal mucosal fold as an index of oviducal growth. Mucosal folds in all regions of the oviduct increased significantly (P < 0.0001) from 4 to 28 wk of age. Concentrations of plasma 17β-estradiol increased from 20 to 28 wk of age, when it stabilized. Mucosal folds in the oviducts of sexually active hens were highest in the uterine region and lowest in the infundibular lip. Intercorrelations among 17β-estradiol concentration, height of mucosal folds, and oviducal weight were strong and positive in these birds. Most of the oviduct epithelium consisted of pseudostratified columnar ciliated epithelium. Both the height of oviducal folds and peripheral estradiol concentrations increased significantly from 20 to 28 wk of age, which confirms the role of estradiol in oviducal growth in the avian species. The height of oviducal mucosal folds appears to be a good measure of oviducal growth

Histological structure and age-related changes in the luminal diameter of the excurrent duct system of guinea cocks (Numida meleagris) and associated changes in testosterone concentrations

As little information is available on the reproductive system of guinea fowl (Numida meleagris), a study was conducted on 49 male guinea fowl to document the histological structure and developmental changes in the luminal diameter of the ducts within the excurrent duct system and associated changes in concentrations of testosterone. Age-related changes were analyzed using the Kruskal-Wallis test and medians separated by the Mann-Whitney U-test. Tubuli recti were clearly visible in the guinea fowl and the rete testes were both intracapsular and extracapsular. Regardless of age, the luminal diameter of the proximal ductuli efferentes was the largest, while that of the connecting duct was the smallest. The luminal diameter of all ducts within the epididymal region increased (P < 0.001) monthly until 20 wk of age, and then increased marginally every month thereafter. Peripheral testosterone concentrations also peaked at 20 wk of age and declined thereafter. In adult birds, the ductus deferens enlarged posteriorly, from an average of about 279 μm cranially to 678 μm caudally. Peripheral testosterone concentrations strongly and positively correlated with the luminal diameter of ducts within the excurrent duct system. The pattern of increase in the luminal diameter of all ducts followed the pattern of testosterone secretion in these birds, which indicates that testosterone concentrations may be closely related to the development of the excurrent duct system in male guinea fowl

Histological structure and age-related changes in the luminal diameter of the excurrent duct system of guinea cocks (Numida meleagris) and associated changes in testosterone concentrations

As little information is available on the reproductive system of guinea fowl (Numida meleagris), a study was conducted on 49 male guinea fowl to document the histological structure and developmental changes in the luminal diameter of the ducts within the excurrent duct system and associated changes in concentrations of testosterone. Age-related changes were analyzed using the Kruskal-Wallis test and medians separated by the Mann-Whitney U-test. Tubuli recti were clearly visible in the guinea fowl and the rete testes were both intracapsular and extracapsular. Regardless of age, the luminal diameter of the proximal ductuli efferentes was the largest, while that of the connecting duct was the smallest. The luminal diameter of all ducts within the epididymal region increased (P < 0.001) monthly until 20 wk of age, and then increased marginally every month thereafter. Peripheral testosterone concentrations also peaked at 20 wk of age and declined thereafter. In adult birds, the ductus deferens enlarged posteriorly, from an average of about 279 μm cranially to 678 μm caudally. Peripheral testosterone concentrations strongly and positively correlated with the luminal diameter of ducts within the excurrent duct system. The pattern of increase in the luminal diameter of all ducts followed the pattern of testosterone secretion in these birds, which indicates that testosterone concentrations may be closely related to the development of the excurrent duct system in male guinea fowl

Spermatogenesis and cellular associations in the seminiferous epithelium of Guinea cock (Numida meleagris)

The study describes the steps of spermiogenesis and stages of seminiferous epithelial cycle in breeding guinea cocks. Epoxy resin embedded sections were employed for the determination of the stages of seminiferous epithelial cycle in the guinea fowl. Acrosomic granules aided in identifying the initial steps of spermiogenesis, while nuclear morphological changes facilitated the identification of subsequent stages. Eleven steps of spermiogenesis and 9 stages of seminiferous epithelium were recognised in the guinea fowl testis. Three spermatogonial types, namely, spermatogonial A, B and intermediate types were identified in the guinea fowl seminiferous epithelium. Spermatogonial A and preleptotene spermatocytes had the largest (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Age-related changes in the gross anatomy of the reproductive organs, and associated steroid hormone profiles in male and female guinea fowls (Numida meleagris)

Owing to the paucity of information on the reproductive biology of guinea fowls, a study involving a total of 132 birds was conducted, and this documented the developmental changes in the gross anatomy of the reproductive organs of males and females from hatching until 32 weeks of age (WOA), and associated steroid hormone changes. Testicular anatomical biometric traits increased significantly (p < 0.0001) from 8 WOA, and stabilised between 16 and 20 WOA, while peripheral testosterone concentration peaked at 20 WOA. Correlations among all testicular biometric characteristics were strong and positive (p < 0.0001). Similarly peripheral testosterone concentrations strongly (p < 0.01) and positively correlated with all the testicular anatomical biometric traits. In the female guinea fowl, the ovary and oviduct were discernible and measurable at hatching. Significant (p < 0.0001) increases were seen in ovarian and relative ovarian weights, and oviducal weights and lengths between 24 and 28 WOA. Plasma 17β-oestradiol decreased gradually to a very minimum at 16 WOA, and then began to increase gradually until 28 WOA when it plateaued. Peripheral progesterone concentrations on the other hand increased gradually from 4 WOA and peaked at 12 WOA, and then fluctuated considerably thereafter. Correlations among ovarian/oviducal anatomical parameters were strong (p < 0.0001) and positive. Similarly, peripheral oestradiol concentrations strongly (p < 0.0001) and positively correlated with all ovarian/oviducal anatomical parameters. Testicular anatomical biometric traits stabilised between 16 and 20 WOA, coinciding with peak peripheral testosterone concentrations, while ovarian/oviducal parameters recorded huge increases between 24 and 28 WOA, and may be under the influence of oestradiol

Spermatogenesis and cellular associations in the seminiferous epithelium of Guinea cock (Numida meleagris)

The study describes the steps of spermiogenesis and stages of seminiferous epithelial cycle in breeding guinea cocks. Sections embedded in epoxy resin were employed for the determination of the stages of seminiferous epithelial cycle in the guinea fowl. Acrosomic granules aided in identifying the initial steps of spermiogenesis, whereas nuclear morphological changes facilitated the identification of subsequent stages. Eleven steps of spermiogenesis and nine stages of seminiferous epithelium were recognized in the guinea fowl testis. Three spermatogonial types, namely, spermatogonial A, B and intermediate were identified in the guinea fowl seminiferous epithelium. Spermatogonial A and preleptotene spermatocytes had the largest (P &lt; 0.05) nuclei diameters in the seminiferous epithelium, whereas round spermatids had the least. Within germ cells, no significant (P > 0.05) differences were found among birds in spermatogonial A and intermediate spermatogonial nuclei diameters. Spermatogonial B, preleptotene primary spermatocyte, type I spermatocyte (primary spermatocyte in prophase I), and round spermatid nuclei diameters were, however, bigger (P &lt; 0.05) in some birds than others. The classification of the seminiferous epithelial cycle in the guinea fowl was similar to that described in other birds and mammals

Testis size and asymmetry in the Guinea Fowl (Numida Meleagris): a test of the compensation hypothesis

Despite numerous studies on testicular asymmetry in birds, there are still inconsistent reports on the pattern of asymmetry in species belonging to various phylogenetic groups and exhibiting diverse lifestyles. In addition, there is a lack of clarity on whether functional differences exist between the left and right testes despite differences in size, as well as no evidence of naturally occurring compensation in testis size in terrestrial and galliform birds. A study involving 400 Guinea Fowl (Numida Meleagris) cocks was conducted to determine asymmetry and compensatory growth in the testes as well as age-related changes in absolute and relative testicular asymmetry. The left testis had significantly higher weight, volume and relative weight than the right testis. Similarly, populations of round spermatids, type I spermatocytes, total germ cell, Sertoli efficiency, actual and apparent seminiferous tubular diameters and testicular sperm production were higher in the left than the right testis. Correlations between the left and right testicular gross anatomical and histological biometric traits were strong and positive. Left biased asymmetry was recorded in the Guinea Fowl. Absolute testicular asymmetry increased with age, but tended to stabilise from 20 weeks of age, while relative testicular asymmetry remained stable throughout. Both absolute and relative testicular asymmetries were higher in breeding than non-breeding males. Compensatory growth was recorded in both testes with no difference in the degree of compensation. The left biased asymmetry observed in the Guinea Fowl was reflected in functional differences between the two testes

Seasonal changes in pasture biomass and grazing behaviour of cattle in the Guinea Savanna agroecological zone of Ghana

Spatial and temporal availability of pasture vegetation and cattle grazing behaviour in three seasons (intermediate season [IM], peak season [PS] and dry season [DS]) in the Guinea Savanna agroecological zone of Ghana was examined. The frequency of occurrence of three species groups (grass, legume and forbs) and biomass yield was estimated in 1 m² plots. The grazing behaviour of 18 cows from six herds was monitored over three days per animal. Season affected the prevalence of species groups with grasses being most dominant in all seasons. Most grazing lands were heavily grazed in IM and DS but moderately grazed in PS. Whilst harvested rice fields represented the most frequently grazed land in DS, fallowed hard pans were used in PS and IM. Biomass yield was highest in DS owing to the contribution of crop residues from harvested farmlands. Carrying capacity was linked to biomass production and averaged 0.55 in DS, 0.38 in PR and 0.21 in IM. Animals spent less time outside the kraal in PS than IM and DS. Walking time was higher in DS than in IM and PS. Less than 20% of the time on pasture was spent on resting, watering and social interaction across seasons.Keywords: carrying capacity, grazing behaviour, rangeland, savanna, tropical livestock uni