Animal Production Science in the 21st Century
RNA interference is a recently described biological phenomenon that is conserved across higher organisms, which disrupts the translation of mRNA into proteins. This process can be utilised for targeted knockdown of specific proteins, resulting in altered animal function. The broad potential for this technology to alter animal development, physiological transitions, and to combat disease, as well as the barriers to adoption in animal agriculture, are explored.
Our current environmental challenges, including worldwide abnormal weather, global warming and pollution, necessitate a new and innovative strategy for animal production for the next generation. This strategy should incorporate not only higher-efficiency production, but also advanced biological concepts and multi-functional agricultural techniques, into environmentally friendly systems. In this review, we describe how to control productivity of livestock by nutritional stimulus in foetuses and neonates, or bring out the potential of animals to their maximum level, using the application of foetal and neonatal programming based on epigenetics for livestock production, especially ruminant production with grass resources.
The lining of the gastrointestinal tract is the body’s largest and most vulnerable external surface. To optimise the digestion and absorption of nutrients and to defend against pathogens and toxins, the lining has an extensive repertoire of sensory mechanisms. These signal to the gut endocrine system, the nervous system, the immune system and local defence in order that digestive efficiency and gut health are optimum.
Under- or over-stimulation of the immune system is detrimental to pig health and productivity. The complexity associated with the immune system, factors influencing its activation, and the subsequent impacts on animal metabolism, are reviewed. Potential management strategies are suggested for optimising the immune response for pigs reared in any specific environment.
In sheep and cattle, maternal nutrition or various causes of placental insufficiency can have indelible effects on fetal development, leading to postnatal variation in productive functions including meat and wool production, and reproduction. These effects appear to be mediated through epigenetic changes in the prenatal genome and other mechanisms. Deeper understanding and more accurate quantification of these phenomena will be needed to enable their incorporation into systems for the management and, potentially, improvement of breeding flocks and herds.
Current animal nutrition systems based on nutrient supply and animal characteristics may predict performance but are inadequate to predict retail yield and composition. The relationship between oxygen uptake, visceral and muscle protein mass, and energy expenditure can be used to explain variation in animal growth and composition with regard to nutritional changes over time. This paper explores independent evidence supporting an existing model linking protein metabolism to animal performance and body composition, and identifies data gaps for future research.
Ruminants as compared to equids and marsupials produce some three-fold amounts of the greenhouse gas, methane, per unit of pasture intake. The nutrient requirements of all species on forage based diets are largely met by microbial fermentation.in the forestomach of ruminants and marsupials but in equids in the caecum–large intestines. Fermentation in the gut of animals is a process that produces end products of volatile fatty acids and metabolic hydrogen. Metabolic hydrogen must be removed immediately to prevent feedback lowering of the fermentation rate. In various microbial ecosystems, metabolic hydrogen is removed by reduction to hydrogen and/or methane (both have low solubility in water) or to soluble acetate. The large volumes of gases so produced are readily removed in ruminants by eructation (belching). In marsupials there are no such mechanisms as eructation. To explain the lack of methane production by marsupials relative to ruminants, the danger or damage theory of evolution of immunity put forward by Matzinger is invoked. It is argued that marsupials have developed immune secretions into their forestomach that prevent the establishment of methanogens and support the growth of acetogens (acetate producers), thus removing any gas pressure build up that would damage vital organs. Similarly, in the equine the upper caecum–large intestine there is no easy mechanism to release gases until the digesta is close to the anus where it can be released by flatus.
Phytases, carbohydrases and proteases are key animal feed products used to improve feed efficiency and nutrient utilisation and reduce environmental waste. Studies evaluating enzyme efficacy in pigs and poultry rely on nutrient digestibility results to highlight the nutrient sparing effects of the enzyme or enzyme combination. Here we highlight the challenges associated with digestibility assays and show that results do not always correspond to improved growth or carcass yield, leading to misleading interpretations about the efficacy or nutrient sparing nature of the enzymes supplied in the diet.
The administration of antimicrobials to poultry for growth promotion has been linked to the global health crisis of antimicrobial resistance, resulting in consumer demand for products free of antimicrobial residues. This review discusses developments in alternatives to antimicrobials for managing gut health. The findings highlight the potential for using in-feed nutraceuticals, such as probiotics and prebiotics, as alternatives to antimicrobials, to create a healthy gastrointestinal environment and prevent and treat intestinal diseases.
Horse owners commonly overfeed proteins and this practice has consequences on the environment and sustainability of equine operations, in particular, in increasingly urbanised areas and areas close to waterways. Nutritionists and scientists require more data on how equids utilise dietary proteins, so as to make recommendations on best feeding practices. A conceptual prediction model of nitrogen and amino acid requirements for equids is proposed. The need to generate more knowledge on protein quality of feed ingredients and the efficiency of N and AA utilisation is highlighted.
Increased efficiency in farming is sometimes seen as inevitably in conflict with good animal welfare. The aim of this article is to show that the conflict can be resolved or at least reduced by showing the financial benefits of high welfare standards. Financial arguments reinforce rather than replace ethical arguments for good welfare.
Society is becoming increasingly concerned about the welfare of animals kept in intensive production systems. This review examines the risks to welfare for beef cattle within commercial feedlots in Australia and identifies established and developing measures of welfare. To allow the industry to show continuous improvements in welfare, accurate, reliable and repeatable measures of welfare are needed to quantify the physical and psychological state of cattle in these systems.
Heat stress is a multifaceted issue that negatively impacts the welfare and productivity of livestock worldwide. It reduces the production of animal products for human consumption and increases rates of morbidity and mortality in livestock. Therefore, improving on and developing effective mitigation strategies that either prevent heat stress or assist in recovery following exposure to high ambient temperatures is essential to maintain appropriate animal welfare standards and increase production efficiency.
Indigenous yellow cattle (Bos indicus) and Asiatic swamp buffalo (Bubalus bubalis) are important livestock species in Laos. Data from 2011 showed that the majority of farm households with large ruminants were smallholders, with the average numbers of farm household with cattle and buffalo of 5.3 and 3.4, respectively. This paper identifies the strategic interventions that may increase the supply of cattle and buffalo and improve rural livelihoods in Laos and the Greater Mekong Subregion.
ASKBILL is a web-based program that provides accurate forecasts to help producers better manage sheep well-being and productivity. The program uses biophysical models, customised by user inputs, localised daily weather updates and 90-day climate forecasts. The predictive functionality will be particularly useful in managing risks and production opportunities that involve the interaction of nutritional status and climatic or parasite events.
Livestock production is facing new challenges from consumers and operating environments, and, so, the role of animal science must also change to adequately solve these complex problems. The increasingly diverse next generation of animal science graduates has less traditional career pathways and links to primary industries, and will require new methods of mentoring and professional development to support the needs of livestock producers. Integrating other disciplines and systems approaches with species- and discipline-specific science will be essential to ensuring a sustainable future for livestock production in Australia.
