Growth performances of exotic indigenous crosses under semi-arid conditions in Botswana

Crossbreeding as a method of increasing production has been widely used for a number of years. Crossbreeding is the mating of two or more different breeds. This combines the genes of two or more breeds and hence the characteristics of all. Crossbred calves frequently performed better than the pure bred calves of either of the parent breeds. Crossbreeding strategies for increasing productivity are based on information on breed and heterosis (hybrid vigour) effects on traits of economic importance. Hybrid viguor has particular advantages in improving low heritable traits such as calf survival, reproductive performance and maternal ability.Main indigenous cattle breeds on which beef production in Botswana is based are Tswana and Tuli. These breeds have evolved by natural selection and are well adopted to the semi-arid and arid conditions prevailing in Botswana. Tswana and Tuli breeds are well recognized in Botswana for their higher fertility and mothering ability. (Buck and Light, 1982). But they are inferior to some exotic breeds, when their postweaning growth rates and yearly weights are considered. Exotic breeds, although they have desirable production characteristics, they lack resistance to the stresses of semi arid to arid conditions. Strategy to improve the beef production could be to combine the adaptation traits of the indigenous breeds with the desirable production traits of the exotic breeds. Thus the dam lines of the indigenous breeds could be crossed with the sire line of the exotic breeds

Developing selection criteria for breeding heifers for Asian dairy production system with special emphasis to South Asia

Dairy plays an important role in social and economic development in South Asia. Dairy development in these countries aims to alleviate poverty, hunger and provide livelihood support in terms of income and employment generation to the millions of landless and small holder dairy farmers. Milk production in South Asia has increased steadily over the last decade. Bangladesh, India, Pakistan and Sri Lanka have realized the growth of 1.5%, 4.1%, 4.9% and 0.6%, respectively, in total national milk production from 1993 to 2003 (FAO statistics). Countries in South Asia are experiencing economic growth, population growth and a shift toward higher valued foods and livestock products. The above socio economical changes are expected to influence the per capita consumption of meat, milk and dairy production in this region (Dong, 2005). Consumption of milk and dairy products has been expanding dramatically with income growth, population growth, urbanization and dietary changes (Beghin, 2005 and Fuller et al 2005). Dong (2005) identified that income growth, population growth and urbanization changes explained about 60% or more of dairy consumption expansion in Asia. Three-fold increase in meat, milk and dairy product consumption is expected in South Asia from 1965 to 2030 (Jutzi, 2005)

New module for prediction of reproductive traits EBV in Breedplan

BREEDPLAN publishes EBVs for days to calving (DTC) from natural mating (NAT) as the key measure of genetic merit for female reproduction. More recently, oestrus synchronization and artificial insemination (AI) have become more widely used in beef cattle in Australia to improve reproductive efficiency. The aim of this study was to develop a reproductive module to predict reproductive performance in beef cattle in Australia by using mating outcomes from AI, NAT from females and scrotal circumference (SC) in males. The study analysed mating and calving data collected on Angus cattle in Australia and New Zealand using the events-based recording system introduced in 2010. Genetic parameters for 1st, 2nd and 3rd parities conception rate (CR) to AI and DTC from NAT were estimated. Mean CR from 1st, 2nd and 3rd parities of AI were 51.5%, 56.2% and 70.4% and for DTC of NAT were 303, 308 and 305 days, respectively. Estimated heritability for CR from 1st, 2nd and 3rd parities were 0.15, 0.12 and 0.10 and for DTC were 0.05, 0.11 and 0.14, respectively. Moderate negative genetic correlations (-0.41 to -0.10) were estimated between CR and DTC of all three parities and were significantly lower than 1 suggesting that they were different traits. Therefore, there are benefits in genetic evaluation from including AI data and modelling parities as different traits

Estimated Additive and Non-additive Breed Effects and Genetic Parameters for Ultrasound Scanned Traits of a Multi-breed Beef Population in Tropical Australia

Direct additive, dominance and genetic parameters for ultrasound scan traits of a multi-breed population involving European, British, Sanga and Brahman breed types were estimated. A generalized ridge regression technique was used to eliminate high associations among some of the genetic effects in the model. Clear breed type effects were observed for all scanned traits. European breeds had negative and positive direct additive genetic effects for fat and eye muscle area, respectively in both heifers and bulls. British, Sanga and Brahman had positive direct additive effects for scan traits in heifers and bulls. Estimated heterosis of Brahman crosses were higher than non Brahman crosses for fat traits and ranged from 2% to 13%. The estimated heritabilities for rump fat, rib fat and eye muscle area of heifers were 0.36, 0.34 and 0.36 and for bulls 0.33, 0.23 and 0.39, respectively

Genetic Parameters of First Lactation Milk Yield Under Low, Medium and High Production Systems in Kenya, using Test-Day Random Regression Model

The aim of this study was to estimate genetic parameters for test-day milk yield in different production systems in Kenya. 10,923, 19,049 and 26,287 first lactation test-day records from multiple breeds under low, medium and high production systems, respectively, were analysed. On average cows under high production systems were younger and had a higher test-day milk yield than in low and medium production systems. A model fitting fourth order Legendre polynomials was found to be the most parsimonious and was therefore used to model the data. Additive genetic and permanent environmental variances were heterogeneous along different days in milk and between production systems. Heritability and repeatability were also different between days in milk and production systems. Heritability was on average 27%, 48% and 48% and repeatability 72%, 83% and 78% under low, medium and high production systems, respectively. Genetic correlations ranged from -32%, 34% and 45% to unity between daily milk yield in different days in milk under low, medium and high production systems, respectively. These parameters indicate that random regression using Legendre polynomial order four can be used to model test-day milk yield under the three production systems in Kenya. The observed heterogeneity of variance indicates that genetic parameters should be estimated within production systems for sustainable genetic improvement

Genetic analysis of dairy cattle performance under extensive, semi-intensive and intensive production systems under tropical climate in Kenya

Genetic parameters for milk and fertility traits of dairy cattle managed under extensive, semi intensive and intensive production systems in Kenya were estimated. Univariate and bivariate analyses were used to estimate genetic parameters for 305 days milk yield, lactation length, age at first calving, and calving interval. The heritability estimates for milk yield were moderate to high and ranged from 0.17 to 0.34. Estimated heritability for calving interval was low under all three production systems. Moderate to high heritability was estimated for lactation length and age at first calving. All the estimates varied among the production systems. Genetic correlation estimates among milk yield and fertility traits were negative. Production system specific parameters are essential to achieve optimum genetic gain under the three production systems in Kenya