Dynamic changes of rumen microbiota and serum metabolome revealed increases in meat quality and growth performances of sheep fed bio‑fermented rice straw

Background Providing high-quality roughage is crucial for improvement of ruminant production because it is an essential component of their feed.Our previous study showed that feeding bio-fermented rice straw(BF)improved the feed intake and weight gain of sheep.However,it remains unclear why feeding BF to sheep increased their feed intake and weight gain.Therefore,the purposes of this research were to investigate how the rumen micro-biota and serum metabolome are dynamically changing after feeding BF,as well as how their changes influence the feed intake,digestibility,nutrient transport,meat quality and growth performances of sheep.Twelve growing Hu sheep were allocated into 3 groups:alfalfa hay fed group(AH:positive control),rice straw fed group(RS:negative control)and BF fed group(BF:treatment).Samples of rumen content,blood,rumen epithelium,muscle,feed offered and refusals were collected for the subsequent analysis.Results Feeding BF changed the microbial community and rumen fermentation,particularly increasing(P<0.05)relative abundance of Prevotella and propionate production,and decreasing(P<0.05)enteric methane yield.The histomorphology(height,width,area and thickness)of rumen papillae and gene expression for carbohydrate trans-port(MCT1),tight junction(claudin-1,claudin-4),and cell proliferation(CDK4,Cyclin A2,Cyclin E1)were improved(P<0.05)in sheep fed BF.Additionally,serum metabolome was also dynamically changed,which led to up-regulating(P<0.05)the primary bile acid biosynthesis and biosynthesis of unsaturated fatty acid in sheep fed BF.As a result,the higher(P<0.05)feed intake,digestibility,growth rate,feed efficiency,meat quality and mono-unsaturated fatty acid concentration in muscle,and the lower(P<0.05)feed cost per kg of live weight were achieved by feeding BF.Conclusions Feeding BF improved the growth performances and meat quality of sheep and reduced their feed cost.Therefore,bio-fermentation of rice straw could be an innovative way for improving ruminant production with mini-mizing production costs.

Animal Disease Research: Key Issues

Livestock and fish production has been growing rapidly in recent decades, driven by the increasing demand for animal-source food. In the last 25 years, the global per capita food demand for all animalsource food has increased by more than 40 kg per person per year [1]. Most of the increase in consumption and production is occurring in low- and middle-income countries (LMICs), particularly in Asia and Latin America. This demand is driven in turn by increasing populations, growing wealth, and urbanization. Much of the demand is supplied by poultry, pork, milk, and fish—sectors that can more easily respond to demand by intensification [2].

Seasonal Variations and Its Impacts on Livestock Production Systems with a Special Reference to Dairy Animals:An Appraisal

Seasonal climatic variations is one of the most important environmental issues at present,the devastating impact of which is visualized on the ecology,ecosystem,and species survival.The livestock sector,which has been the source of animal protein for ever-increasing human masses,is subjected to the increased environmental temperature and higher frequency of extreme events.The impact of a high degree of heat stress is found to have a direct bearing on the milk production,growth,feed intake,reproductive efficiency,and disease incidence of the animals.The environmental temperature above the thermo-neutral zone of the animals has not only been adversely affecting the productivity and survival in the intensive livestock production systems,but the impact is equally seen in the extensive systems.Besides reduced milk production and change in composition,the impact of heat stress on dairy animals,in general,can be seen from the reduction of sperm quantity and quality in case of male and a marked decline in fertility and embryo quality in the case of females.The paper analyses varied aspects of climate change impacts on production,productivity,reproduction,and health of livestock,with a special focus on dairy animals.

Prevalence of Salmonella in Fresh Produce Tomatoes Sold in Open Market in Ouagadougou, Burkina Faso

Tomato is a widely consumed vegetable in Burkina Faso and throughout the world. However, when handled improperly, it can serve as a vector of pathogen transmission to human if ingested raw or through cross-contamination with cooked food. This study aimed to determine the prevalence of Salmonella spp from tomatoes sold in the markets of Ouagadougou, Burkina Faso and characteristics of vending conditions. One hundred and ninety-eight (198) different tomato samples were randomly purchased from one hundred and thirteen (113) different vendors in the markets of Ouagadougou. The samples were examined and classified into three categories according to their texture and the level of deterioration. The prevalence of Salmonella spp identification was determined using standard microbiological methods. A survey was conducted using a questionnaire on transport and vending conditions for tomatoes. In total, Salmonella prevalence was 19.19% in all tomato’s samples analyzed and was 18.18% for intact category, 22.73% in D2 category and 16.67% in category D4. The survey revealed poor transport and sales conditions for the majority of tomato sellers. The present study revealed the presence of Salmonella in tomatoes samples. These results highlight the risk associated with the consumption of tomatoes if hygienic practices are not respected during tomatoes handling and preparation. The results of the study also show the need to wash tomatoes systematically after purchase with a disinfectant, especially tomatoes sold in open markets in developing countries.

Effects of urea plus nitrate pretreated rice straw and corn oil supplementation on fiber digestibility,nitrogen balance,rumen fermentation,microbiota and methane emissions in goats

Background: Urea pretreatment is an efficient strategy to improve fiber digestibility of low quality roughages for ruminants. Nitrate and oil are usually used to inhibit enteric methane(CH4) emissions from ruminants. The objective of this study was to examine the combined effects of urea plus nitrate pretreated rice straw and corn oil supplementation to the diet on nutrient digestibility, nitrogen(N) balance, CH4 emissions, ruminal fermentation characteristics and microbiota in goats. Nine female goats were used in a triple 3 × 3 Latin Square design(27 d periods). The treatments were: control(untreated rice straw, no added corn oil), rice straw pretreated with urea and nitrate(34 and 4.7 g/kg of rice straw on a dry matter [DM] basis, respectively, UN), and UN diet supplemented with corn oil(15 g/kg soybean and15 g/kg corn were replaced by 30 g/kg corn oil, DM basis, UNCO).Results: Compared with control, UN increased neutral detergent fiber(NDF) digestibility(P < 0.001) and copies of protozoa(P < 0.001) and R. albus(P < 0.05) in the rumen, but decreased N retention(-21.2%, P < 0.001), dissolved hydrogen concentration(-22.8%, P < 0.001), molar proportion of butyrate(-18.2%, P < 0.05),(acetate + butyrate) to propionate ratio(P < 0.05) and enteric CH4 emissions(-10.2%, P < 0.05). In comparison with UN, UNCO increased N retention(+34.9%, P < 0.001) and decreased copies of protozoa(P < 0.001) and methanogens(P < 0.001). Compared with control, UNCO increased NDF digestibility(+8.3%, P < 0.001), reduced ruminal dissolved CH4 concentration(-24.4%, P < 0.001) and enteric CH4 emissions(-12.6%, P < 0.05).Conclusions: A combination of rice straw pretreated with urea plus nitrate and corn oil supplementation of the diet improved fiber digestibility and lowered enteric CH4 emissions without negative effects on N retention. These strategies improved the utilization of rice straw by goats.

Mitochondrial DNA diversity and origin of indigenous pigs in South China and their contribution to western modern pig breeds

Indigenous pigs in South China are valuable genetic resources with many specific and unique characters, which have played an important role in the establishment of some western modern pig breeds. However, the origin and genetic diversity of indigenous pigs in South China have not been fully understood. In the present study, we sequenced 534 novel mitochondrial DNA (mtDNA) D-loop and assembled 54 complete mitogenome sequences for all 17 indigenous pig breeds from Fujian, Guangdong, Guangxi and Hainan in South China. These data were analyzed together with previously published homologous sequences relevant to this study. We found that all 13 coding genes of the mitogenomes were under purifying selection, but ND1 had the most variable sites and CYTB contained the most non-synonymous SNPs. Phylogenetic analysis showed that all indigenous pigs in South China were clustered into the D haplogroup with D1a1, D1b, D1c and D1e sub-haplogroups found to be dominant. Haplotype and nucleotide diversities of D-loop sequences ranged from 0.427 to 0.899 and from 0.00342 to 0.00695, respectively, among which all pigs in Guangdong had the lowest diversity. The estimates of pairwise FST, gene flow (Nm) and genetic distance (Da) indicated that most of these indigenous pig breeds differentiated from each other significantly (P<0.05). Among the western modern breeds, Berkshire and Yorkshire had significant Asian matrilineal footprints from indigenous pigs in South China, especially the Spotted pigs distributed in Guangdong and Guangxi. The neutrality test (Fu’s FS) indicated that indigenous pigs from Fujian and Guangxi had gone through recent population expansion events (P<0.05). It is concluded that indigenous pigs in South China were most likely derived from the Mekong region and the middle and downstream regions of Yangtze River through Guangxi and Fujian. Our findings provide a complete and in-depth insight on the origin and distribution pattern of maternal genetic diversity of indigenous pigs in South China.

Impact of grazing on soil, vegetation and ewe production performances in a semi-arid rangeland

Controlled grazing is considered a good management strategy to maintain or increase the live weight of livestock and to reduce vegetation degradation of rangelands. The present study investigated soil characteristics, aboveground vegetation biomass dynamics and controlled grazinginduced changes in the live weight of local ewes in the semi-arid rangeland of Ahmadun, Ziarat, Balochistanprovince of Pakistan. An area of 115 ha was protected from livestock grazing in April 2014. In June 2015, soil characteristics within 0-30 cm depth i.e. soil organic matter(SOM), mineral nitrogen, p H and texture in controlled and uncontrolled grazing sites were assessed. Aboveground vegetation biomass measured in early(June) and late summer(August) in 2015 and 2016. The nutritional value i.e. crude protein, phosphorus(P), neutral detergent fiber(NDF), acid detergent fiber(ADF), calcium(Ca), magnesium(Mg) and potassium(K) of dominantplant species were assessed at the beginning of experiment in 2015. Vegetation cover of controlled and uncontrolled grazing sites was also measured during the two years of the study period using the Veg Measure software. From June to November in2015 and 2016, controlled and uncontrolled livestock grazing sites were grazed on a daily basis by local ewes with a stocking rate of 2 and 1 head ha^(-1) respectively. Results reveal that the organic matter contents of coarse-textured, slightly alkaline soil of the study site were in the range of 9.4-17.6 g kg^(-1) soil and showed a strong positive correlation with aboveground vegetation biomass. The biomass of plants was 56.5% and 33% greater at controlled than uncontrolled grazing site in 2015 and 2016 respectively and plant cover was also higher at controlled than uncontrolled grazing site in both years The nutrient contents were significantly(P<0.05)lower in grasses than shrubs. In both years, the controlled grazing increased the weight gain of ewes about two folds compared to the uncontrolled grazing.The results indicate that controlled grazing improved the vegetation biomass production and small ruminant productivity.

Comparative Laying Performance, Egg Quality, Fertility and Hatchability of Guinea Fowl with Tilili, Horro and Potchefstroom Koekoek Chicken Breeds

A study was conducted to compare laying performance, fertility, hatchability, and egg quality of guinea fowl (GF) with Horro (HR) and Tilili (TL) local chicken and Potchefstroom Koekoek (PK) exotic chicken. Forty five layers from each genotype and 6 cocks from each chicken genotype and 9 cocks from GF were used in 3 replications in a completely randomized design. Commercial layer feed was used ad libitum for the study that lasted 29 weeks. Daily DM intake per hen was 85, 114, 103 and 137 g (SEM = 3.1) for GF, HR, TL and PK, respectively, and was in the order of GF < TL < HR < PK. Final body weight of hens was highest for PK (2490 g), intermediate for HR (1983 g) and lowest for TL (1671 g) and GF (1641 g). Egg number per production week followed a similar trend like that of DM intake and was 71, 101, 75 and 121 (SEM = 0.5) for GF, HR, TL and PK, respectively. Both fertility and hatchability of fertile eggs for GF were 57%, which were lower than the mean of chicken genotypes by 41% and 34%, respectively. Embryonic mortality was higher for GF (early, middle and late was 15.8%, 10.0%. and 17.4% respectively) compared to chicken genotypes. Chick weight was highest for PK, intermediate for HR and TL and lowest for GF;while chick length was in the order of PK > HR > TL > GF. Average egg weight was higher for PK eggs (46.4 g), intermediate for HR (43.5 g) and TL (42.3 g), and lowest for GF (35.9 g). Eggshell weight and thickness were higher for GF than chicken genotypes. Haugh unit was similar among genotypes. Such differences among poultry genotypes could be reflection of previous selection and breeding interventions, which are apparently more in chicken genotypes than GF. A possible more stressful condition of the confined environment for GF versus chicken genotypes could have also contributed to such differences. This study highlighted the need of implementing future selection and breeding schemes to improve the performance of GF and TL birds to the level achieved by other genotypes.

Serum Biochemical and Meat Fatty Acid Profiles of Different Chicken Genotypes

Serum biochemical and meat fatty acid profile of different chickens were studied. A total of 144 mixed sex matured chickens of Cosmopolitan (C), Improved Horro (H), Cosmopolitan♂*Improved Horro♀(CH), Improved Horro♂*Cosmopolitan♀ (HC), Indigenous (L) and Koekkoek (KK) were used to determine serum biochemical, of which 36 chickens were also used for fatty acid profile study. Completely randomized design in 6 × 2 factorial arrangements was set up. Serum biochemical and fatty acid profiles were determined by Roche/Hitachi cobas c 501 and gas liquid chromatography (GC) procedures, respectively. There were significant differences (P ≤ 0.001) in Total cholesterol (TC), Triglyceride (TG), Low-density lipoprotein (LDL) and High-density lipoprotein (HDL) among genotypes and between sexes. HDL was inversely related with TC, TG and LDL. Male had significantly higher (P ≤ 0.001) TC, TG, LDL but lower HDL than female. SFA, (Myristic, Pentadecanoic and Palmitic acids) had significantly (P < 0.05) varied among genotypes. However, Margaric (P ≤ 0.01) and stearic (P ≤ 0.001) acids were significantly different between sexes. Myristoleic and Palmitoleic acids significantly vary (P ≤ 0.05) among genotypes and between sexes. Oleic (P ≤ 0.01) and Eicosenoic (P ≤ 0.001) significantly influenced by sex. Moreover, Linoleic had significantly (P ≤ 0.01) affected by genotypes. Nevertheless, α-linolenic acid significantly (P ≤ 0.01) varied between sexes. The serum biochemical differed across genotypes and between sexes. The difference in the number of carbons, double bond and position of the double bond could affect fatty acid profile among genotypes and between sexes. Chicken products with higher level TC, TG, LDL and SFA might affect human health problems. It could also be interesting topic for future studies.

Factors Affecting Arab Goat Flock Dynamics in Western Lowlands of Ethiopia

The study was conducted to estimate flock dynamics of western lowland Arab goat and to assess their contribution to income of smallholder farmers in Kurmuk and Assosa districts, western Ethiopia. Flocks of 30 households were monitored for a period of 12 months in 2016. Data were analyzed using the general linear model procedure of SAS and two-way interaction effects were fitted in the model and retained when found significant in the preliminary analysis. The study result indicates that total entrances for all flock were significantly (p < 0.05) higher in dry and hot-cool seasons than wet season. Most of the entrance was kids born in hot-cool season (January) (4.0 ± 0.42) and hot-dry season (May) (5.4 ± 1.09) for Assosa and Kumruk study sites, respectively. Kid mortality constituted the greater part of outflow. High kid mortality was occurred during July, February, January, and September. Most of the sell of castrated goats were occurred in September and April for both small and large flocks targeting holidays celebrated during this months. Male goat owners had significantly lower goat production potential (GPP) value than female (0.47 ± 0.02 vs. 0.52 ± 0.02). The GPP was lower in small flock than in large flock (0.48 ± 0.02 vs. 0.51 ± 0.02). Higher GPP was recorded in the months of January, February, and March for both large and small flocks. The off-take was higher (P < 0.05) in Assosa (0.06 ± 0.01) than Kumruk (0.02 ± 0.02) district. The average goat production efficiency (GPE) was higher (P < 0.05) in Assosa large (193.23 ± 20.0) and small flocks (93.44 ± 17.3) than Kumruk large (84.71 ± 15.6) and small flocks (33.33 ± 26.3).The production efficiency recorded was not comparable to the potential that the farmers had to sell goats or consume goats’ meat and milk. The lower goat production potential observed for small flocks implies that high mortality rates severely restrict receiving higher benefits from goat. Therefore, in order to optimize the productivity of goats flock dynamics, developing health intervention strategies that target reduction of kids’ mortality is imperative.

Begait Goat Production Systems and Breeding Practices in Western Tigray, North Ethiopia

A study was undertaken to characterize production system, breeding practices and production constraints of Begait goat in Kafta humera district, northwestern lowlands of Ethiopia. Personal observations, focus group discussions and a detailed structured questionnaire were used to collect data from 150 respondents (99 small-scale and 51 large-scale farmers). Mixed crop-livestock production system was found to be the dominant farming system in the study district. The farmers kept a variety of livestock species including goats, sheep, cattle, chickens and donkeys. Small ruminants are the most numerous and are of great importance in the area. Goats are herded with sheep in the open fields by the young boys in the family/hired grazers. They have a number of roles though mainly kept as a source of cash income. Breeding was generally uncontrolled. Size, growth rate and libido were the most frequently reported traits in selecting bucks, whereas does were selected based on size, twining ability and milk yield. Effective population size and rate of inbreeding were calculated by considering random mating and flocks were not mixed. The major constraints hampering goat production in the area were water scarcity, feed and grazing land shortages and insufficient veterinary services among the others. Therefore, addressing these constraints is important to design a successful genetic improvement scheme in the area for goat.

Sheep Production and Breeding Systems in North Western Lowlands of Amhara Region, Ethiopia: Implication for Conservation and Improvement of Gumz Sheep Breed

A questionnaire survey and focused group discussions were conducted to characterize sheep production systems and traditional breeding practices of Gumz sheep as an essential step for designing the Gumz sheep breed conservation and improvement programme. A total of 240 households were included in the study during the period of November 2016 to March 2016. Smallholder farmers kept sheep as a source of income, meat and wealth with an index value of 0.43, 0.19 and 0.15, respectively. Important purposes of large scale farmers for keeping sheep were source of cash income (0.57) and investment opportunity (0.22). Average sheep flock sizes were 17.25 ± 0.68 and 90.63 ± 5.38 at smallholder and large scale production systems, respectively. Smallholder sheep flocks’ composition was 7.47 ± 0.28 Gumz, 3.68 ± 0.25 Rutana and 4.52 ± 0.22 Rutana-Gumz crossbred sheep. The corresponding figures for large scale farms were 21.2 ± 1.4, 30.7 ± 1.69 and 24.7 ± 1.47 sheep. The average numbers of rams in the smallholder sheep flocks were 0.31 ± 0.04 Gumz, 0.39 ± 0.04 Rutana and 0.24 ± 0.03 crossbreds, respectively. The corresponding figures for large scale farms were 3.10 ± 0.13 Rutana and 0.90 ± 0.14 crossbreds. The Gumz sheep was large in number, but farmers prefer Rutana and its crosses than Gumz in both systems. Diseases, stock theft and labour shortage were reported as the main constraints of sheep production. Although the pure Gumz breed meets the multifaceted roles of sheep for the smallholder farmers, the Gumz sheep population was declining in number in the study area due to uncontrolled breeding with Rutana and high preference of farmers for crossbreds over Gumz sheep. It is observed that there is a risk of dilution and loss of genetic diversity of the Gumz sheep. Hence, we recommend designing of conservation-based breeding program to conserve the locally adapted Gumz breed as well as to improve sheep production and productivity in the area through rational utilization of all the three genotypes.

Validating the Classification of Smallholder Dairy Farming Systems Based on Herd Genetic Structure and Access to Breeding Services

Smallholder dairy farming in Africa is classified into rural, peri-urban and urban systems. The major classification criterion is demographic. Dairy systems are extensively characterized, but not based on rigorous statistical analyses. We validated this classification based on herd genetic structure and identify determinants of within-system variations, taking Ethiopia as a case study. Discriminant function analysis correctly classified 38% - 50.6% of the 360 sampled farms into the three systems. Multinomial logistic regression analysis showed that rural and peri-urban farmers were 1.26 (P < 0.1) to 1.45 (P < 0.001) times more likely to keep local and low grade crossbreds and fewer high grade crosses (P < 0.05;odds ratio = 2.35) than the urban farmers. In the rural system, proportion of high grade crosses declined and low grades increased over generations, whereas in urban system the reverse was observed. Access to breeding services and land resources significantly determined the adoption of crossbred dairy herd within systems. In conclusion, considering farms within systems as a uniform unit to target development interventions may not be appropriate and thus farm topologies and system specific determinants of farmers’ breeding strategies need to be considered to design and introduce appropriate breeding interventions.

Comparative Growth Performance, Carcass Characteristics and Meat Quality of Local Horro and Exotic Cockerels of Tropical Origin Fed Growers Diet

Growth performance, carcass characteristics and meat quality of male chickens were evaluated using eight-week-old 360 cockerels from three exotic (Koekoek, Kuroiler and Sasso-R) and one Ethiopian indigenous (Horro) genotypes. Cockerels in each breed (90) were randomly allocated into three replications of 30 birds each and housed in deep litter pens for the experiment that lasted for 8 to 16 weeks. The experiment was arranged in a Completely Randomized Design. Seven birds per breed were slaughtered at the end to determine carcass yield, chemical composition and quality attributes of meat. The Kuroiler breed has higher body weight, body weight change (1621.8 g), average daily gain (28.9 g/day), daily feed consumption (127.4 g/day) and better feed conversion ratio (4.40) than other breeds. The Kuroiler breed has heavier slaughter weight (2716.3 g), dressed carcass weight (2201.0 g), eviscerated carcass weight (1905.1 g), breast weight (537.7 g), thigh weight (303.1 g) and drumstick weight (274.8 g) than other breeds. Total edible offal was higher for Kuroiler (324.2 g) and Sasso-R (306.1 g), intermediate in Koekoek (204.4 g) and low in Horro (152.4 g) breed. The relative proportion of breast and drumstick (% slaughter weight) were lower in Koekoek and Sasso-R (17.3 and 8.9) breeds, respectively. Abdominal fat weight (13.7 g and 1.02%) was lowest in Horro. Sasso-R showed higher percent edible offal weight (13.4%) than Horro breed (11.4%). The DM content in breast and thigh meat was higher for Horro breed than the rest. The CP content in the breast and thigh meat was lower for the Kuroiler and Koekoek breeds, respectively. Higher EE in the thigh meat was recorded for Sasso-R (8.9%), whereas, EE content in the breast meat was similar (3.4% - 3.7%) among the breeds. Flavor, tenderness, juiciness and general acceptability of breast and thigh meat were not affected by breed. The highest net return was observed in the Kuroiler breed. Based on the results obtained, it is suggested that the Kuroiler breed can be used for cockerel meat production in Ethiopia where intensive broiler production is not well developed.

Assessing Animal Disease Prevalence and Mortality in Smallholder Dairy Farms under Contrasting Management Practices and Stressful Environments in Tanzania

In dairy farming, deploying effective animal husbandry practices minimise disease infections and animal mortality. This improves animal health and welfare status, which is important in tropical smallholder dairy farming, where animals are persistently exposed to multiple environmental stresses. The hypothesis of this study was that animals managed in positive deviants and typical farms suffer different levels of disease infections and mortality, whether under low- or high-stress environments. The study adopted a two-factor nested design with farms contrasting in the level of animal husbandry (positive deviants and typical farms) nested within environments contrasting in the level of environmental stresses (low- and high-stress). A total of 1,999 animals were observed over 42 month period in the coastal lowlands and highlands of Tanzania. The disease prevalence was lower (p < 0.05) in positive deviant farms than in typical farms under low-stress (10.13 vs. 33.61 per 100 animal-years at risk) and high-stress (9.56 vs. 57.30 per 100 animal-years at risk). Cumulative disease incidence rate was also lower (p < 0.05) in positive deviant farms than in typical farms under low-stress (2.74% vs. 8.44%) and high-stress (2.58% vs. 14.34%). The probability of death for a disease infected dairy cattle was relatively lower in positive deviant farms compared to typical farms under low-stress (0.57% vs. 8.33%) and high-stress (0.60% vs. 6.99%). Per 100 animal-years at risk, the mortality density of cattle was lower (p < 0.05) in positive deviant farms compared to typical farms, 15.10 lower in low-stress and 2.60 lower in high-stress. These results show that compared to typical farms, positive deviant farms consistently attained (p < 0.05) lower animal disease infections and subsequent deaths, regardless of the level of environmental stress that the animals were exposed to. This implies that positive deviant farms deployed animal husbandry practices that more effectively minimised animal disease infections and deaths and therefore could maintain their animals in better health and welfare status.

Performance of Smallholder Dairy Farming in Nakuru County, Kenya

The Kenya dairy sub-sector has been undergoing developments since the 1980s in the areas of adoption of intensive dairy farming, especially zero grazing. There have been concerted efforts by the government and other development partners to commercialize the sub-sector so as to make it more profitable to farmers, especially smallholder farmers, but the profitability in the sector continues to be variable with some smallholder farmers making losses. The causes of the varying profits have not been empirically established, with the influence of institutional arrangements and financial factors contributing to this inconsistency not fully established. This study dwelt on establishing the critical institutional arrangements and financial factors that constrain the profitability of smallholder dairy farmers in Nakuru County. A multi-stage sampling procedure was used to select respondents. Data were collected by structured interviews at the farm level. Data Envelopment Analysis （DEA） was used to come up with profit efficiency rankings among the farmers, and the Frontier Model was used to establish the factors that constrain profit efficiency. The mean efficiency according to the results was 86%. The farm and farmer characteristics that were significant in explaining profitability efficiency according to the frontier results were： feeding system, breed type, and gender. The financial characteristics included debt amount and debt asset ratio. Additionally, issues of trust were also found to have an effect on profitability, and they included trust in local buyer price, trust in unit of measurement of institutional buyer, and trust in unit of measurement of middlemen.

Perforin Expression in <i>Theileria parva</i>Specific Cytotoxic T Cells Correlates with Cytotoxicity

Theileria parva is a protozoan parasite that causes the disease East Coast fever in cattle which results in major economic losses in Eastern, Central and Southern Africa. Efforts to generate vaccines involve measurements of cytotoxic activity since CD8 cells are believed to be responsible for protection of the animals. CTL assays are time consuming, and may require use of radioactive material and they also impose a considerable amount of in vitro work, which may skew the response compared to ex vivo assays. Hence it would be beneficial to identify other markers that correlate with the cytotoxicity. In this in vitro study we examined if the number of tetramer positive CD8 cells and the staining intensity of these correlated with lysis of the target cells. Furthermore, we investigated if the expression of the activation marker perforin correlated with the cytotoxicity. Perforin is involved in permeabilization of the cell membrane of the target cell. Bulk CTL lines and purified CD8 cell lines generated from cattle of the A18 BoLA (MHC) type were analysed for the Theileria parva specific immune responses using a peptide-MHC tetramer and antibodies for perforinin FACS analysis. Thelysis of target cells was determined by a chromium release assay. Results demonstrate that the percentage of tetramer positive cells, in six cell lines generated against the whole parasite, correlate with killing of PBMC pulsed with the peptide. The product of the percentages of perforin and tetramer double positive cells and the net MFI of perforin showed a perfect correlation with the cytotoxicity of the peptide pulsed PBMC. Likewise, the product of percentage perforin positive cells and the staining intensity had the best significant correlation with killing of the pulsed PBMC. The present results suggest that perforin could be a possible biomarker for the cytotoxicity to Theileria parva infections/immunizations.

Nutrient Composition of Pastures in Kayunga District, Uganda: A Preliminary Investigation with Implications for Seasonal Supplementation in Grazing Ruminants

Proximate nutrient composition (crude protein, non-fiber carbohydrates, crude fiber, and ash), fiber fractions (neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin), and both macro (calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na), and sulfur (S)) and trace (copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn)) mineral profiles were quantified in mixed pasture samples collected during the wet (n = 8) and dry (n = 15) seasons in north central Uganda. Metabolizable and Net Energy values for dairy production were estimated based on standard calculations, and samples were compared seasonally. Crude fat (p = 0.05) and lignin (p = 0.01) values were lower in the dry compared with the wet season, linked with reduced plant growth. Crude protein (13.0% of dry matter (DM)), fiber fractions, and calculated energy content did not vary seasonally in this data set, and reflected chemical components of a grass-dominated system that appeared energetically limiting for production livestock. Mineral constituents varied more dramatically by season, with Ca, Mg, Cu, and Mn lower (all 0.05) and K higher in the dry season. Sodium was deficient in these pastures, whereas Ca, P, Mg, S, Cu, and Zn concentrations may have been only marginally sufficient, particularly to meet needs for lactation, dependent on season. These limited data suggest that a high-energy mineral supplement may prove beneficial in meeting nutritional and production needs of multiple grazing ruminant species in this region, particularly during dry seasons.

Constraints on Camel Meat and Milk Marketing and Strategies for Its Improvement in Northern Kenya

A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development （PICD）, Focus Group Discussions （FGD）, among other methods. In a second step, field testing of an intervention on milk and meat hygiene was carried out at household level. Survey results indicated that about 50% of marketable camel milk was not sold, 30% of marketed camel milk per annum was sold in sour state at US$ 0.13 lower that the price of a litre of fresh milk while processed meat got spoiled along the chain. Annual economic losses associated with milk spoilage were estimated at US$ 961,538.5. Preliminary findings of the field testing indicated that an additional 3 million litres of camel milk was sold in fresh state, giving an annual saving of US$ 384,615.4. Increased profitability of up to 60% compared to 30% before the intervention was reported among nyirinyiri processors. In conclusion, economic potential of the camel could be fully exploited by facilitating adoption of interventions such as hygiene, among others at all levels of the camel milk and meat value chains.

Nitrogen fertilization effects on grain quality of durum wheat (<i>Triticum turgidum</i>L. var. durum) varieties in central Ethiopia

Four released durum wheat varieties, two medium tall (Arsi-Robe and Kilinto) and two recently released semidwarfs (Ude and Yerer) were evaluated under five different N rates (0, 60, 120, 180 and 240 kg·ha-1) in 2005/06 growing season at Akaki and Debre Zeit, central Ethiopia. The quality responses of durum wheat varieties to different N-fertilizer rates and the N responses between tall and short durum wheat varieties were assessed. Protein and gluten content, vitreous kernel count, thousand kernel weight, test weight and lodging were considered. Vitreous kernel count, protein and gluten content were higher at Debre Zeit than at Akaki. Unlike Debre Zeit, there were significant relationships between response variables and fertilizer levels at Akaki. Lodging slightly affected the medium tall varieties at Debre Zeit whereas it was not a problem at Akaki. At Akaki, varieties response to each additional N rate was entirely below the quality standard set by ICC, 2000 except for thousandkernel weight. Therefore, it is unwise to promote durum wheat scaling up/out program for quality production at Akaki.