Genetic Selection for Thermotolerance in Ruminants

Variations in climatic variables (temperature, humidity and solar radiation) negatively impact livestock growth, reproduction, and production. Heat stress, for instance, is a source of huge financial loss to livestock production globally. There have been significant advances in physical modifications of animal environment and nutritional interventions as tools of heat stress mitigation. Unfortunately, these are short-term solutions and may be unsustainable, costly, and not applicable to all production systems. Accordingly, there is a need for innovative, practical, and sustainable approaches to overcome the challenges posed by global warming and climate change-induced heat stress. This review highlights attempts to genetically select and breed ruminants for thermotolerance and thereby sustain production in the face of changing climates. One effective way is to incorporate sustainable heat abatement strategies in ruminant production. Improved knowledge of the physiology of ruminant acclimation to harsh environments, the opportunities and tools available for selecting and breeding thermotolerant ruminants, and the matching of animals to appropriate environments should help to minimise the effect of heat stress on sustainable animal genetic resource growth, production, and reproduction to ensure protein food security.

Molecular Diversity Analysis of Jattal and Dera Din Panah Goat Breeds of Pakistan using Microsatellite Markers

This paper evaluates the genetic diversity of goat breeds in Pakistan, a country blessed with a wide range of goats spread throughout with distinct features contributing to a rich Animal Genetic Resource. The genetic diversity of two goat breeds (Jattal and Dera Din Panah) was assessed with 25 animals representing the two breeds using 16 microsatellite markers. The mean observed and expected heterozygosity of both goat breed populations were observed as 0.83+0.21. The average number of observed alleles was 3.6+1.6 for all loci. The mean polymorphic information content for a goat breed was 0.45, indicating the usefulness of markers panel. Highest Nei’s standard genetic distance (Ds) value of 0.0612 was observed between Jattal and Dera Din Panah goats, and the mean Fst value was 0.013. The measures of genetic variation revealed a good scope for effective improvement, conservation, and designing national breeding policies, in future, for Pakistan goat breeds.

Effects of two finishing diets on growth performance, carcass characteristics and feeding behaviour of Slovenian Cika and Simmental young bulls

This study aimed at comparing the effects of a traditional finishing roughage-based diet and a higher energy diet, on growth, carcass characteristics, and feeding behaviour of Slovenian Cika and Simmental bulls (20 per breed). The experimental diets were: extensive (EXT) based on grass silage, and semi-intensive (S-INT) in which a part of the roughage was replaced with maize silage and sunflower meal. Each diet was fed ad libitum to 10 Cika (547 days old) and 10 Simmental (442 days old) bulls housed in group pens of five animals each. Growth performance was similar in both breeds, but Cika reached commercial finishing 1 month earlier than Simmental (139 vs 167 days; P = 0.016). Bulls fed S-INT had higher final weight (645.3 vs 590.1 kg; P = 0.05), average daily growth (1.05 vs 0.83 kg; P = 0.026), and feed intake (11.7 vs 10.6 kg dry matter (DM)/day; P < 0.001) than EXT bulls. Regardless of breed and diet, bulls ate 77–80% of the daily DM in the first 8 h after feed delivery. Bulls fed EXT showed longer standing (406.4 vs 355.8 min; P < 0.001) and eating (217.2 vs 155.3 min; P < 0.001) and shorter ruminating (77.5 vs 92.9 min; P < 0.001) times than S-INT bulls during the first 8 h of feed delivery. Cika bulls had lower full reticulo-rumen weights relative to slaughter weights (8.7 vs 10.7%; P = 0.002) than Simmental. The positive findings obtained with Cika cattle should encourage farmers to finish their young Cika male stocks for beef production, thus contributing to the maintenance of this animal genetic resource, and also to increase the energy density of the grass-based finishing diets by feeding supplements.