Ruminant production

Eckard, R. J., Grainger, C., and de Klein, C. A. M. (2010). Options for the abatement of methane and nitrous oxide from ruminant production A review. Lifestock Sci. 130,47-56. 

Organic livestock husbandry methods and the microbiological safety of ruminant production systems... 

Differences in feeding regimes and husbandry methods between organic, Mow input and conventional ruminant production... 

Conventional livestock production systems can be very diverse and this diversity is influenced by economic, geographic, environmental and cultural factors. Conventional inputs for direct use in ruminant production include many types of plant feeds (i.e. forages, cereals, soybeans, etc.), industrial by-products (i.e. molasses, distiller s dried grain, meat bone meal, etc.), feed... 

Microbiological risks associated with ruminant production... 

Waller, P. J. and Thamsborg, S. M. (2004). Nematode control in green ruminant production systems . Trends in Parasitology, 20(10), 493-497. 

Preston, T.R. and Leng, R.A. (1987) Matching Ruminant Production Systems with Available Resources in the Tropics and Subtropics. Penambull books, Armidale, New South Wales, Australia. 

Although more research is needed to document consistent modes of action, capsules containing CLA produced by microbial fermentation are sold as food supplements. CLA in ruminant products are considered natural, and levels of up to 1.5 percent of the fat in beef and 6 percent of the fat in cheeses made from spring pasture milk, have been reported. 

In an attempt to prevent the further international spread of the disease, importation of animals from infected countries has been banned. Thus, for example, the United States in 1989 banned the importation of live ruminants and most ruminant products from the United Kingdom and other countries having BSE. The ban was extended to European products in 1997 after the discovery of the disease in some countries there. 

Because the presence of CLA in the human diet is reliant on ruminant products, this chapter first addresses the synthesis of CLA in ruminants. The presence of CLA in ruminant milk and meat is related to rumen fermentation and its synthesis by microorganisms through the process of biohydrogenation (BH) of dietary unsaturated fatty acids. Thus, the effect of diet and processes within the rumen is reviewed. The role of endogenous synthesis of CLA in mammalian tissues has been discovered, and this will be discussed also first as it contributes to the occurrence of CLA in ruminant products and second the significance of endogenous synthesis as a source of CLA in humans and other species. 

The end-products of rumen microbial metabolism of greatest interest with regard to CLA metabolism in the body are the various CLA isomers and the tram-11 monoenoic acid VA. The latter, being a substrate for A-9-de-saturase, is converted to RA in animal tissues. Hay and Morrison (1970) reported the distribution of monoenoic isomers of milk fat, and the content of various CLA and other 18 2 isomers in the fat of ruminant products has been summarized by Parodi (2003). 

Australia (79) 500-1 500 Range of CLA likely in ruminant products, intake derived from a National Dietary Survey... 

Ruminant products are by far the major contributor of CLA to the diet. Because these products contain twofold or more VA than CLA, and Turpeinen et al. (77) showed that 20% of this VA was converted endogenously to (XA, then the effective physiological dose of CLA will be CLA intake x 1.4. This important area of VA bioconversion to CLA requires further research, investigating, for instance, ethnic and individual variation and the effect of other dietary components on A -desaturase activity. 

CLA, an intermediate in the ruminal biohydrogenation of linoleic acid to stearic acid (37), is present in highest concentrations in foods of ruminant origin (12). The predominant isomer of CLA present in beef is the cis-9,trans-ll isomer (38). Biohydrogenation of PUFA in the ramen significantly limits attempts to manipulate the fatty acid content of ruminant products. However, the CLA content of beef muscle is regulated mainly by the type of diet being fed and related mainly to the concentration of PUFA in the diet. 

Tannins were primarily considered as anti-nutritional biochemicals due to then-adverse effects on feed intake and nutrient utilization (Kumar and Vaithiyanathan 1990). Nevertheless in recent years, they have been recognized as nsefnl phytochemicals for beneficially modulating the rumen microbial fermentation. The effects of tannins on ruminant production have been published in the past, which primarily focused on the adverse effects of tannins on animal systan, with some discussion on their positive effects on protein metabolism and prevention of bloat (Mangan 1988 Kumar and Vaithiyanathan 1990 Aerts et al. 1999 Barry and McNabb 1999 McSweeney et al. 2001a Min et al. 2003 Mueller-Harvey 2006 Waghom 2008). This chapter focuses on the effects of tannins on ruminal microbial populations that affect N metabolism, methanogenesis and ruminal biohydrogenation process in the mmen. 

The first animal production study aimed at identifying factors that affect RA concentrations in ruminant products (milk) was conducted by Jiang et al. (1996). Since then, the research on dietary factors that modulate the BH process and thus fatty acid composition of milk and meat has greatly increased. The exploration of plants secondary metabolites as dietary components capable to manipulate ruminal BH is very recent and will be reviewed here. 

There are several recent reviews on the effect of secondary compounds including saponin or saponin containing plants on rumen function and animal production (Hart et al. 2008 Patra and Saxena 2009a). This review describes in more details saponin extraction methods, the stmctural diversity of saponins and their effect on rumen microbes and rumen fermentation. The information presented here could provide wider opportunities for the utilization of saponins and saponin-containing plants as feed additives in sustainable and environmental friendly ruminant production. 

CLA is another fatty acid that might have beneficial effects such as helping to control obesity, but the effects in humans do not appear to be as great as in animals. There are CLA-containing products, such as nulk-based drinks. CLA is composed of a mixture of various positional and geometrical isomers whose distribution varies between the two main sources commercial CLA or ruminant products with enhanced levels of CLA. Different isomers can produce different physiological effects, so the different sources may have different activities. Notably, the 10t,12c isomer may be responsible for effects on body composition and is high in commercial CLA, but normally at low levels in dairy products. 

Morgavi, D.R, Kelly, W.J., Janssen, P.H. and Attwood, G.T. (2013) Rumen microbial (meta)genomics and its application to ruminant production. Animal 7 Suppl 1, 184-201. 

Significantly higher [NEFA] (PKI.OIS) during food deprivation and significantly lower [BHBA] (P=0.013) can be explained by mobilization of body fat reserves and by a diminished ruminal production of SCFA leading to a reduced delivery of ketone bodies from rumen mucosa to blood. The intensity of fat mobilization varies between animals and thus, an 1.7 to 3.5-fold increase of the blood [NEFA] was observed. 

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