A. Valle Zárate

Effects of the Genetically Reduced Feather Coverage in Naked Neck and Featherless Broilers on Their Performance Under Hot Conditions

Under hot conditions, contemporary commercial broilers do not reach their full genetic potential for growth rate, body weight (BW), or breast meat yield because dissipation of their excessively produced internal (metabolic) heat is hindered by the feathers. Therefore, it was hypothesized that heat stress can be alleviated by using the naked-neck gene (Na) or the featherless gene (sc). The study consisted of 4 experimental genetic groups (fully feathered, heterozygous naked neck, homozygous naked neck, featherless), progeny of the same double-heterozygous parents (Na/na +/sc), and commercial broilers. Birds from all 5 groups were brooded together until d 21 when one-half of the birds from each group were moved to hot conditions (constant 35 degrees C), and the others remained under comfortable conditions (constant 25 degrees C). Individual BW was recorded from hatch to slaughter at d 45 and 52 at 25 and 35 degrees C, respectively, when breast meat, rear part, heart, and spleen weights were recorded. Body temperature was recorded weekly from d 14 to 42. Feather coverage significantly affected the thermoregulatory capacity of the broilers under hot conditions. With reduced feather coverage (naked-neck), and more so without any feathers (featherless), the birds at 35 degrees C were able to minimize the elevation in body temperature. Consequently, only the featherless birds exhibited similar growth and BW under the 2 temperature treatments. The naked-neck birds at 35 degrees C showed only a marginal advantage over their fully feathered counterparts, indicating that 20 to 40% reduction in feather coverage provided only limited tolerance to the heat stress imposed by hot conditions. Breast meat yield of the featherless birds was much greater (3.5% of BW, approximately 25% advantage) than that of their partly feathered and fully feathered counterparts and the commercial birds under hot conditions. The high breast meat yield (at both 25 and 35 degrees C) of the featherless broilers suggests that the saved feather-building nutrients and greater oxygen-carrying capacity contribute to their greater breast meat yield. Because of these results, further research on genetically heat-tolerant broilers should focus on the featherless phenotype.

Evaluation of biological and economic efficiency of smallholder pig production systems in North Vietnam

This study evaluates smallholder pig production systems in North Vietnam, comparing a semi-intensive system near a town with good market access, where a Vietnamese improved breed has replaced the indigenous pig breed, and an extensive system away from town, where the indigenous breed still prevails. Fieldwork was conducted in 64 households in four villages. Repeated farm visits yielded 234 structured interviews. Data were analysed by linear models and non-parametric tests. Production inputs and outputs were quantified, and feed use efficiency and economic efficiency were assessed. The gross margin was higher for semi-intensive production with the improved breed, while the benefit–cost ratio was higher under extensive conditions with the indigenous breed. The net benefit did not differ between systems. Twenty-four per cent of farmers yielded a negative net benefit. In one village under extensive conditions, live weight output from indigenous sows with crossbred offspring compared positively with the output from semi-intensive production with improved genotypes, but was associated with high inputs, making production inefficient. Results indicate that improved genotypes might not be an efficient production alternative for saving-oriented production with limited resource supply. Suitability of evaluation parameters, farmers’ production aims, and factors impacting the production success in different systems are discussed.

SMALL RUMINANT PRODUCTION IN TWO MIXED-FARMING SYSTEMS OF SOUTHERN ETHIOPIA: STATUS AND PROSPECTS FOR IMPROVEMENT

Small ruminants are an integral part of mixed-farming systems throughout southern Ethiopia. Yet, they have received little research attention or institutional support. Characterizing the existing small ruminant production systems and analysing their production constraints are important tools to diagnose the status and trends of the systems, and thus to identify areas for future interventions. A survey was conducted between April and July 2004 in the Adilo and Kofele areas of the southern mixed-farming systems of Ethiopia to explore reasons for keeping small ruminants and to evaluate the existing status of and the prospects for the small ruminant sector. Additional information was obtained during discussions with key informants who had experience of small ruminant keeping. Small ruminants fill several roles in the study area. However, the principal purpose of keeping sheep and goats was to generate cash income. Sheep milk consumption was widespread around Kofele unlike most agricultural systems in the country. Nearly all respondents in Adilo reported fattening their sheep before sale, while such a practice was uncommon in Kofele. Informal insurance schemes were evolving among the sheep keepers in Adilo, and these can be considered as entry points for future interventions. The common problem identified from both individual interviews and group discussions was feed shortage. The identification of alternative feed resources and strategic feeding management might be options for development. Small ruminant disease was the major constraint in Kofele, where marshy areas are increasingly assigned for grazing in the rainy season as suitable land is more and more used for cropping. The growing demand for meat from small ruminants, the improving transportation infrastructure and the experience of farmers in small ruminant keeping are providing opportunities to enhance the contribution of the sector. A thorough monitoring of the productive and economic performance of small ruminants is required to capture the full picture of their contribution thereby directing possible intervention areas to maximize benefits to the farmers.

Community-based livestock breeding programmes: essentials and examples.

Breeding programmes described as community-based (CBBP) typically relate to low-input systems with farmers having a common interest to improve and share their genetic resources. CBBPs are more frequent with keepers of small ruminants, in particular smallholders of local breeds, than with cattle, pigs or chickens with which farmers may have easier access to alternative programmes. Constraints that limit the adoption of conventional breeding technologies in low-input systems cover a range of organizational and technical aspects. The analysis of 8 CBBPs located in countries of Latin-America, Africa and Asia highlights the importance of bottom-up approaches and involvement of local institutions in the planning and implementation stages. The analysis also reveals a high dependence of these programmes on organizational, technical and financial support. Completely self-sustained CBBPs seem to be difficult to realize. There is a need to implement and document formal socio-economic evaluations of CBBPs to provide governments and other development agencies with the information necessary for creating sustainable CBBPs at larger scales.

Identification and quantification of subsidies relevant to the production of local and imported pig breeds in Vietnam

Livestock diversity contributes in many ways to human survival and well-being, while its loss reduces options for attaining sustainable agriculture and universal food security. The current rapid rate of loss of this diversity is the result of a number of underlying factors. While in some cases changes in production systems and consumer preferences reflect the natural evolution of developing economies and markets, in other cases production systems, breed choice and consumer preferences have been distorted by local, national and international policy. In the context of a widespread threat to local pig breeds in Vietnam, this paper identifies and quantifies the level of agricultural subsidies that are currently contributing to this process of breed substitution. Producer subsidies—which tend to improve the competitiveness of imported breeds and their crosses over local breeds—are shown to be considerable, and mitigating measures are now urgently needed to avoid an irreversible loss of livestock diversity.

Traditional llama husbandry and breeding management in the Ayopaya region, Bolivia

The llama claims the largest population of the domestic South American camelids, most of which are raised in Bolivia. More than 53,000 rural families are dedicated to llama husbandry as part of their livelihood strategy. Contemporary Andean societies deliberately select animals for specific traits and employ substantial livestock management to secure subsistence. This study presents traditional llama husbandry and breeding management activities in the Ayopaya region, Bolivia. Traditional selection traits for male and female llamas are documented and assessed by a ranking and a ratio-scaled evaluation. Husbandry and management parameters are in concordance with other studies conducted in the region, but show a high variation. Average llama herd sizes are rather small (μ = 45.6). In some herds, breeding males are utilized for a long time and mix with other herds, causing concerns about inbreeding. Preferred trait groups for llama males according to farmers’ responses were body conformation, fibre, testicle conformation, fleece colour and height at withers. Traditional selection criteria generally relate to the phenotype, but also include the commercially interesting fibre trait. The presented results should be considered in breeding and management programmes for the respective llama population to ensure sustainable use of this genetically and culturally valuable resource.

Evaluation of basic and alternative breeding programs for Sahiwal cattle genetic resources in Kenya

The Sahiwal cattle breeding program in Kenya has been operational on an interim basis for over 45 years. However, there have been no systematic efforts undertaken to evaluate its suitability, or to examine how competitive it is compared with other alternative programs in terms of genetic and economic merit. The objective of this study was therefore to evaluate the genetic and economic success of the current basic and alternative Sahiwal cattle breeding programs in Kenya. The breeding programs examined were the current closed nucleus with two breeding strategies: a purebreeding (CNPURE) and a crossbreeding system (CNCROSS) involving Sahiwal sires and East African Zebu dams. An open nucleus with a certain proportion of pastoral-born Sahiwal bulls introduced into the nucleus herds to produce cows was simulated as an alternative breeding program. In this program only a purebreeding strategy (ONPURE) was considered. The breeding strategies were evaluated under two breeding objective scenarios that addressed traditional markets where animals are sold on body size/weight basis and the Kenya Meat Commission where payment is based on carcass characteristics. Sensitivity analyses to changes in nucleus size and gene contribution were also performed. The annual monetary genetic gain and profit per cow for all investigated breeding programs varied within breeding objectives. Closed nucleus purebreeding program was the most attractive economically but less competitive in regard to genetic superiority compared with either CNCROSS or ONPURE. Returns and profits were generally higher for the carcass characteristic basis compared with the body size/weight basis for all evaluated breeding strategies. Expansion of the nucleus size was not attractive because of the associated reduction in genetic and economic benefits. However, gradual importation of pastoral-born sires into the nucleus farms at the current nucleus proportion of 14% was both genetically and economically beneficial. The CNCROSS plays a complimentary role of facilitating the exploitation of trade-offs that exist between the Sahiwal and the locally better adapted East African Zebu, it also represents an intermediate phase in the on-going upgrading program.

Breeding and conservation programmes for Sahiwal cattle genetic resources in the tropics: a review

Studies on Sahiwal cattle genetic resources in the tropics have mainly concentrated on evaluating their performance levels, with only a few published reports describing the breed characteristics. The aim of this study was to critically examine the existing breeding and conservation programmes for Sahiwal cattle in the tropics, focusing on Pakistan, India and Kenya as the core regions of development. The study was based on review of both published and unpublished literature highlighting shortcomings and strengths in the existing strategies, and opportunities for improvement and conservation. The Sahiwal breed is utilized for dairy and beef production under smallholder dairy, pastoral extensive and ranching production systems, both as pure-breds or cross-breds. The necessary components to strengthen the breeding programmes such as performance recording, genetic evaluation and artificial insemination (AI) facilities exist to differing degrees. Breeding and conservation efforts benefit from the technical and financial support from government research institutions which also provide incentives to enhance participation in the programmes. However, breeding goals are rather informal and only defined in terms of high-production levels with functional traits largely ignored. There is need for participatory identification of breeding and production goals, and structured cooperation of the small herds, so as to accommodate the specific contributions of the breed in future breeding and conservation programmes.