Forage availability and its quality in the dry season on smallholder dairy farms in Tanzania

Insights Into the Genetic Architecture of Complex Traits in Napier Grass (Cenchrus purpureus) and QTL Regions Governing Forage Biomass Yield, Water Use Efficiency and Feed Quality Traits

Napier grass is the most important perennial tropical grass native to Sub-Saharan Africa and widely grown in tropical and subtropical regions around the world, primarily as a forage crop for animal feed, but with potential as an energy crop and in a wide range of other areas. Genomic resources have recently been developed for Napier grass that need to be deployed for genetic improvement and molecular dissection of important agro-morphological and feed quality traits. From a diverse set of Napier grass genotypes assembled from two independent collections, a subset of 84 genotypes (although a small population size, the genotypes were selected to best represent the genetic diversity of the collections) were selected and evaluated for 2 years in dry (DS) and wet (WS) seasons under three soil moisture conditions: moderate water stress in DS (DS-MWS); severe water stress in DS (DS-SWS) and, under rainfed (RF) conditions in WS (WS-RF). Data for agro-morphological and feed quality traits, adjusted for the spatial heterogeneity in the experimental blocks, were collected over a 2-year period from 2018 to 2020. A total of 135,706 molecular markers were filtered, after removing markers with missing values >10% and a minor allele frequency (MAF) <5%, from the high-density genome-wide markers generated previously using the genotyping by sequencing (GBS) method of the DArTseq platform. A genome-wide association study (GWAS), using two different mixed linear model algorithms implemented in the GAPIT R package, identified more than 35 QTL regions and markers associated with agronomic, morphological, and water-use efficiency traits. QTL regions governing purple pigmentation and feed quality traits were also identified. The identified markers will be useful in the genetic improvement of Napier grass through the application of marker-assisted selection and for further characterization and map-based cloning of the QTLs.

Major Causes of Calf and Lamb Mortality and Morbidity and Associated Risk Factors in the Mixed Crop-Livestock Production System in Jamma District, South Wollo, Ethiopia

Lamb and calf preweaning mortality and morbidity account for serious losses in sheep and cattle production and are, thus, a major factor in reducing profitability and adversely affecting the sheep and cattle farming. Thus, a prospective cohort study was conducted in Jamma district, Amhara Regional State, to determine the major cause of calf and lamb morbidity and mortality and associated risk factors. A semi-structured questionnaire and clinical assessment of the animals were conducted from 150 households to assess the potential risk factors. Besides, a total of 102 (81 fecal samples and 21 skin scrapings) were collected from 150 clinically ill and suspected animals to identify the cause of morbidity and mortality. The test of difference and correlation between variables were computed using chi-square and generalized linear model analysis. The total morbidity and mortality in calves were 33.3% and 2%, respectively, whereas for lamb, they were 27.3% and 32.5%, respectively. In calf, septicemia (100%) was a major cause of mortality, and diarrhea (54.6%) was the leading cause of calf morbidity followed by skin disease (30.1%), respiratory problems (12%), and septicemia (3.3%). Malnutrition was the most common problem in lambs causing up to 31.3% mortality followed by diarrhea 24% and respiratory problems 21.3%. The presence of a disease in adult cattle was significantly correlated to the presence of disease in calves (p < 0.001; r = 0.35). There was also a significantly higher positive correlation between sickness in adult sheep and lambs (p < 0.001, r = 0.45). Gastrointestinal parasitosis was identified in 82.7% of the samples collected from diarrheic and suspected calves (87.1% positive) and lambs (80% positive). Monezia species in lamb (33.3%) and Coccidia species in the calf (35.9%) had the largest morbidity rate. Ctenocephalides canis (16.7%) and Linognatus species (41.7%) were common ectoparasites identified in calves, while Melophagus ovinus was the only ectoparasite of lambs recovered (62.5%). In conclusion, the high morbidity found in calves and morbidity and mortality in lambs are known to seriously reduce the profitability of the smallholder cattle and sheep production in the area by affecting the availability of replacement animals and causing a detrimental effect on herd expansion and productivity. In further studies, establishing the specific causative agents, control of diseases in the adult, and improvement in feed resources should be the major areas that need to be considered to mitigate calf and lamb morbidity and mortality currently affecting the area.

A survey of management practices and major diseases of dairy cattle in smallholdings in selected towns of Jimma zone, south-western Ethiopia

Context Smallholder dairy farming is becoming an important source of food, income and employment for many urban dwellers in Ethiopia. However, suboptimal productivity is a major constraint due to diseases and poor management practices. Aims The present work aimed at assessing management practices, dairy cattle diseases, and methods used by farmers to identify diseases on smallholdings in selected towns of Jimma zone, south-western Ethiopia. Methods Data for the study were obtained by surveying 52 dairy-keeping farmers by using a semi-structured questionnaire and personal observations. Key results The mean herd size of indigenous and crossbred cattle was 5 ± 0.04 and 2 ± 0.4 respectively. Natural pasture was the main source of feed with supplementation, mainly with agro-industrial by-products, concentrate mixes, non-conventional feeds and crop residues. In total, 75% of the respondents practiced a free-grazing system. Most (64%) of the respondents used natural service for breeding. In all, 64% and 35% of the respondents washed their hands and the teats respectively, before milking. In the order of decreasing percentage of respondents, the most frequently reported dairy cattle health problems were tick infestation, mastitis, lumpy skin disease, blackleg, heart water, facioliasis, trypanosomiasis, foot-and-mouth disease, pasteurellosis, brucellosis and anthrax. Repeated breeding, retained fetal membranes, abortion, stillbirths and dystocia were the common reproductive health problems, in a decreasing order of the reported percentage. Lumpy skin disease was reported as a major cause of calf and lactating-cow deaths. A total of 89% of the respondents used veterinary medicines to treat their sick animals. About 24% of the respondents stated culling of their animals due to old age, lack of space, infertility, feed shortage, need for cash and low production, in a decreasing order of importance. Conclusions The results showed farmers are well knowledgeable in cattle production practices and are actually mitigating effects of most disease challenges in their farms, which may have resulted in low milk productivity. Implications The farmers in the current study had some knowledge of milk production activities that may be recommended for similar settings, especially on how to manage dairy cattle production under smallholder farms, obviously including the occurrence of diseases, which they are managing appropriately with available technologies including vaccines and treatment. These could be used as baseline data by dairy stakeholders and policy makers during the formulation and implementation of policies for sustainable growth and development of smallholder dairy for similar settings.

Calf health and management in smallholder dairy farms in Tanzania

Smallholder farmers' knowledge and practice of dairy calf management on 129 farms with calves less than 10 months of age in Southeastern and Southern Highland areas of Tanzania was assessed. The method of study included both a farm visit and completion of a questionnaire. Most of the farmers were female, with a primary level of education, and majority kept 1-3 milking cows that yielded 6-10 l milk/cow/day. Most of the calves were fed milk using a residual calf suckling system. Weaning age was 3-8 months. Overall, the body condition of the calves was poor, ranged from 1 to 2.5 with a mode of 2. The majority of the farmers believed that helminthosis was the most common disease condition affecting the calves; diarrhea was ranked as the second. Calf death was reported by 20% of the farmers to have occurred in their herd lasting the 2 years prior to the study. Calf body condition score was related to body weight for calves younger than 9 weeks, and older than 23 weeks of age, whereas no such relationship existed in the age group 9 to 23 weeks. The sex distribution was skewed with less male calves being older than 23 weeks. We hypothesize that male calves experience inferior management compared with female calves. This study demonstrates a low level of knowledge on, and poor practices of calf management among the surveyed farmers that suggest the need for educational intervention.