THE NUTRITIVE VALUE AND AGRONOMIC ASPECTS OF SOME FODDERS IN NORTHERN NIGERIA

Digestibility data are presented on the following; Andropogon gayanus hay and bush foggage, Arachis hypogoea (groundnut) haulms, Glycine max (soya-bean) hay. Sorghum vulgare (sorghum) leaves and hay, Stizolobium sp. (velvet bean) hay, Vigna sinensis (cowpea) hay and haulms, and S. vnlgare/Stizolobium sp. mixture. The results are discussed from the agronomic aspect.     

Treatment of rupture of suspensory ligament and superficial flexor tendon in a bull

Rupture of the suspensory ligament at the insertions on the proximal sesamoid bones, and of the superficial flexor tendon of the left fore limb, occurred in an adult Angus bull as a result of fighting. There was severe hyperextension of the metacarpophalangeal (MCP) joint with the dewclaws almost touching the ground. Radiographs revealed severe hyper-extension of the MCP joint with the sesamoid bones aligned directly distal to the metacarpus. Initially, a full length fiberglass cast was applied with the limb partially flexed within the cast and the heels elevated. The cast was replaced twice. The cast was removed after 136 days and the bull was bearing full weight on the limb. Prolonged immobilisation of the limb produced new bone in the area (a normal response in cattle) to cause ankylosis of the traumatized MCP joint and partial ankylosis of the carpus. The bull was being used for pasture breeding one year after the injury.     

Effect of Supplementation of Taurine or Trehalose in Extender on Immunolocalization of Tyrosine Phosphoproteins in Buffalo and Cattle (Karan Fries) Cryopreserved Spermatozoa

The present study assessed the effects of incorporation of Taurine or Trehalose in extender on immunolocalization of tyrosine phosphoproteins, Cryocapacitation and other sperm quality parameters (motility, viability and membrane integrity) in post‐thawed sperm from Buffalo (Murrah) and Cattle (Karan Fries). Six ejaculates from six individual bulls from both species were chosen at random and split into four aliquots: one aliquot without dilution (fresh sample), another diluted in egg yolk tris‐citrate (EYTC) extender and the rest of aliquots with EYTC dilution supplemented with taurine (50 mm ) or trehalose (100 mm ), respectively, and cryopreserved. Following cryopreservation, semen were thawed and assessed for standard semen quality parameters. Extent of capacitation in cryopreserved spermatozoa was measured by inducing in vitro acrosome reaction followed by dual staining. Immunolocalization of tyrosine phosphoproteins was carried out by immunocytochemistry using primary antibody clone pT‐154 (anti‐phosphotyrosine antibody) and FITC‐conjugated secondary antibody. Immunofluorescent signals were analysed for level of protein tyrosine phosphorylation in spermatozoa. Post‐thaw semen evaluation showed supplementation of taurine or trehalose to EYTC extender significantly (p < 0.05) increased motility, viability and membrane integrity of spermatozoa in both species. Percentage of cryocapacitated spermatozoa was significantly (p < 0.05) higher in cattle as compared to buffalo and degree of cryocapacitaion of spermatozoa decreased significantly (p < 0.05) upon supplementation of additives in both the species. It was also found that tyrosine phosphoproteins were localized differentially in fresh and cryopreserved spermatozoa. Supplementation of taurine or trehalose to freezing extender changed the localization of tyrosine phosphoproteins in cryopreserved spermatozoa similar to fresh in both the species. The results obtained clearly indicated that supplementation of taurine or trehalose to EYTC prior to cryopreservation improves Buffalo and Cattle sperm quality in terms of cryocapacitation and immunolocalization of tyrosine phosphoproteins during freezing–thawing process.     

Characterisation of germplasm accessions of Napier grass (pennisetum purpureum and P. purpureum×P. glaucum Hybrids) and comparison with farm clones using RAPD

Fifty six germplasm accessions of the important East African fodder crop Napier grass, Pennisetum purpureum, and its hybrids with P. glaucum, were characterised using 67 random amplified polymorphic DNA (RAPD) fragments. No or very low intra-accession variation was found for 49 of the accessions examined, confirming field observations that this species is predominantly clonally propagated. Comparison of intra and inter-accession variation identified several groups of identical/similar accessions that could be targeted if the collection is to be rationalised, and also highlighted two misplantings of germplasm material during transfer to a field trial site. A neighbour joining dendrogram of Jaccard's similarity estimates, clearly separated 50 accessions of P. purpureum from three P. glaucum individuals, and placed six hybrid accessions in an intermediate position. These groupings were well supported by a nested AMOVA (P<0.001; 29.5% of total variance due to taxonomic delineation). The main group of P. purpureum individuals could be further differentiated into five sub-groups (designated East Africa, Southern Africa, USA1, USA2 and Miscellaneous, to reflect the majority membership of sub-groups) and examination of the within P. purpureum component of the nested AMOVA, found them to be significantly different (P<0.001; 18.8% of variance). Genetic diversity across all accessions was found to be fairly high (Shannon's diversity index 0.306) and thus the collection probably represents a wide genetic base for this species. In addition to germplasm accessions, 25 Kenyan farm clones were also analysed. A principal coordinate analysis found that all but one of the clones clustered with the main P. purpureum group of accessions, indicating that the majority are probably not interspecific hybrids. The origin and pedigree of clones is discussed based on genetic similarity amongst clones and to germplasm accessions.     

Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya

A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70%--suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut-cassava zone was significantly lower (57+/-8% (S.E.)) than in herded-grazing systems (79+/-3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashew nut-cassava and the drier livestock-millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock-millet zone (45+/-6%) than in the other two zones.Analysis was confined to the coconut-cassava zone for B. bigemina and to the coconut-cassava and cashew nut-cassava zones for A. marginale. Mean prevalences of B. bigemina were 40.9+/-9 and 73+/-6% for dairy cattle under stall-feeding and herded-grazing systems, respectively, and increased with age. Antigen prevalences of A. marginale were over 80% in all age groups of cattle in the coconut-cassava and cashew nut-cassava zones. Overall trypanosome prevalence in cattle was <1%. Trypanocidal treatment was uncommon. The variations in antibody prevalence associated with risk factors such as feeding system, agro-ecological zone and age of animal suggest that management system influenced exposure to tick-borne infection (particularly, T. parva infections) in small-holder dairy cattle in coastal Kenya.     

Identification of a target population for immunisation against East Coast fever in coastal Kenya

Two experiments were carried out to identify the target population of cattle for immunisation against East Coast fever (ECF) using the infection-and-treatment method. Firstly, a sentinel-calf study was used to determine the age window for ECF immunisation by determining ages at clinical detection of infection with Theileria parva. Six groups of five naive cross-bred (Bos taurus/Bos indicus) male calves, introduced at intervals of 2 months at a mean age of 26 days, were exposed to natural tick challenge on a high ECF-risk, small-holder farm in the coastal lowland, coconut-cassava agro-ecological zone of coastal Kenya. Secondly, a challenge study evaluated the relationship between the presence of T. parva antibodies and immunity. Ten indigenous adult Zebu cattle and nine Zebu young stock purchased from farmers in the same zone, and eight cross-bred calves (survivors of the sentinel-calf study) were challenged with 10 times the immunising dose of T. parva Marikebuni stock. Twenty-four of these 27 cattle had high antibody titres before challenge. Two cross-bred calves, obtained from an ECF-free area and seronegative to T. parva schizont antigen, also were challenged and used as susceptible controls. Twenty-five (83%) of the 30 sentinel calves contracted ECF over an age range of 36-116 days (mean 72 days). The remaining five calves died of other causes within 2 months of arrival on the farm. Fourteen of the 25 calves survived the infection and developed antibodies to T. parva. Despite tick control, seven of these 14 calves had a second episode of ECF and two died. In total, 13 of the 25 calves that contracted ECF died. Only one of 19 indigenous Zebu animals developed clinical ECF when challenged with T. parva Marikebuni (mild clinical signs with spontaneous recovery). Of the eight cross-bred survivors from the first experiment, only one succumbed to ECF when challenged and it died. Both susceptible cross-bred calves developed severe clinical signs of ECF and one died. The experimental studies show that in the high ECF-risk areas of the coconut-cassava zone of coastal Kenya, immunisation against ECF in cross-bred (B. taurus/B. indicus) cattle should be targeted at an early age (preferably within 1-2 months of birth).     

Comparative Expression Analysis of Gametogenesis‐Associated Genes in Foetal and Adult Bubaline (Bubalus bubalis) Ovaries and Testes

This study was conducted to identify and analyse the expression of gametogenesis‐associated genes and proteins in foetal and adult buffalo gonads of both the sexes. Relative quantification of the genes was determined by qPCR and Western blotting. Immunohistochemistry was also performed for various gametogenesis‐associated proteins in foetal and adult gonads of both the sexes. We observed significantly (p < 0.05) increased expression of primordial germ cell‐specific, meiotic as well as genes associated with oocyte maturation and development in foetal ovaries as compared to the adult ones. However, significantly (p < 0.05) increased expression of proteins associated with oocyte maturation like GDF9 and ZP4 was found in adult ovaries, indicating temporal regulation of mRNA translation during oogenesis. Meiotic genes showed significantly (p < 0.05) increased expression in adult testes as compared to foetal testes and ovaries, indicating onset of meiosis at a later stage in spermatogenesis. In general, the expression of primordial germ cell‐associated as well as meiotic genes was higher in adult testes, indicating the increased biological activity in the organ. Immunohistochemistry revealed localized expression of gametogenesis‐associated proteins in ovarian follicles and seminiferous tubules of testes, while the surrounding somatic tissues were devoid of these proteins. The study gives an understanding of the sequential and temporal events of gene expression as well as mRNA translation during male and female gametogenesis. It could also be concluded that follicles and seminiferous tubules are the functional units of the female and male gonads, respectively, and their function could be enhanced by appropriate chemical and genetic intervention of the somatic tissue immediately surrounding them. This assumes importance in the context that buffalo attains sexual maturity at an older age of 2–3 years and have smaller ovaries with lesser number of primordial follicles in comparison with cattle, which is suggested to be the main reason of their poor breeding performance.     

The Effects of the Periodical Use of In-feed Chlortetracycline on the Reproductive Performance of Gilts and Sows of a Commercial Pig Farm with a History of Clinical and Subclinical Viral and Bacterial Infections

The objective of this study was to assess the effects of in‐feed chlortetracycline (CTC) as a measure of preventing or minimizing infectious problems of reproductive failure in gilts and sows. In a farm of 400 Large White × Landrace gilts and sows with a clinical history of porcine respiratory and reproductive syndrome (PRRS) virus, the animals were treated with CTC. Treatment consisted of 10 g CTC sow/day for 15 days every 3 months. It improved the health status of sows by decreasing post‐farrowing clinical mastitis and vaginal discharges, abortions, return‐to‐oestrus and irregular return‐to‐oestrus rates. These beneficial effects had a positive impact on the performance of the litter. More piglets were born live and weaned. These positive effects improved with repeated use of CTC. The serological evidence of PRRS virus, Leptospira spp. and Chlamydia spp. and the subsequent beneficial use of the antimicrobial agent indicate that reproductive failure, possibly resulting from the bacterial agents can be controlled with in‐feed use of broad spectrum antimicrobials.     

Modelling the Vertical Transport of Pollutants by Fronts

A quantitative study of the amount of air transported between the boundary layer and the free atmosphere is important for understanding air quality and upper tropospheric ozone, which is a greenhouse gas. Frontal systems are known to be an effective mechanism for the vertical transport of pollutants. Numerical experiments have been performed with a simple two-dimensional front model to simulate vertical transport of trace gases within developing cold fronts. Three different trace gases experiments have been done numerically according to the different initial fields of trace gases such as aerosol, ozone and H₂O₂. Trace gas field tilts to the east while the front tilts to the west. Aerosol simulation shows that pollutants can be transported out of the boundary to altitudes of about 10 km. The stratospheric ozone is brought downwards in a tropopause fold behind of the frontal surface. The meridional gradient in trace gas (H₂O₂) can cause a complicate structure in the trace field by the meridional advection.