Ruminant Industry Research Articles

Anthelmintic activity of Cymbopogon martinii, Cymbopogon schoenanthus and Mentha piperita essential oils evaluated in four different in vitro tests

Anthelmintic resistance is a worldwide concern in small ruminant industry and new plant-derived compounds are being studied for their potential use against gastrointestinal nematodes. Mentha piperita, Cymbopogon martinii and Cymbopogon schoenanthus essential oils were evaluated against developmental stages of trichostrongylids from sheep naturally infected (95% Haemonchus contortus and 5% Trichostrogylus spp.) through the egg hatch assay (EHA), larval development assay (LDA), larval feeding inhibition assay (LFIA), and the larval exsheathment assay (LEA). The major constituent of the essential oils, quantified by gas chromatography for M. piperita oil was menthol (42.5%), while for C. martinii and C. schoenanthus the main component was geraniol (81.4% and 62.5%, respectively). In all in vitro tests C. schoenanthus essential oil had the best activity against ovine trichostrongylids followed by C. martini, while M. piperita presented the least activity. Cymbopogon schoenanthus essential oil had LC50 value of 0.045mg/ml in EHA, 0.063mg/ml in LDA, 0.009mg/ml in LFIA, and 24.66mg/ml in LEA. The anthelmintic activity of essential oils followed the same pattern in all in vitro tests, suggesting C. schoenanthus essential oil could be an interesting candidate for nematode control, although in vivo studies are necessary to validate the anthelmintic properties of this oil.

Current strategies for eradication of paratuberculosis and issues in public health

Paratuberculosis is a regional chronic enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP). The first complete description of this disease was made in 1895, but previous reports on clinical cases compatible with this entity can already be found in the literature of early 1800s. Its obvious similarities with tuberculosis gave it the name of paratuberculosis, although it was clearly recognized it was not the same entity as that caused by mammal tuberculosis mycobacteria. Eradication has been considered the ideal goal for control of paratuberculosis, but the lack of efficient diagnostic tools and the high costs involved in testing and culling approaches have shifted the focus to control given the better benefit/cost ratios of more conservative strategies like vaccination. Up to now the control of paratuberculosis has been driven by its negative effects on the ruminant farming industry, however recent growing discussion on its links with human regional enteritis might require control strategies changes if a zoonotic role is considered by Public Health authorities. Paratuberculosis was described nearly 40 years earlier than what is usually considered the first full type description of human regional chronic enteritis or inflammatory bowel disease (IBD) which is pathologically a similar entity. No microbiological evidence was found to link both entities until the 1980s in spite of a number of more or less serious attempts. Afterwards there have been numerous studies showing the association of MAP with human IBD. Microbiological, pathological, immunological, therapeutic and epidemiologic associations have not been considered proof of causality and, currently, no widely accepted consensus has been reached about the etiologic role of MAP in human cases. This puts ruminant farming under suspicion and causes a difficult balance between Public Health precaution and practical control measures.

Feed Enzyme Technology: Present Status and Future Developments

Exogenous enzymes are now well accepted as a class of feed additives in diet formulations for poultry and pigs to overcome the negative effects of anti-nutritional factors, and to improve digestion of dietary components and animal performance. An overview of the current status of feed enzyme technology, including the different type of enzymes and modes of action, is provided. Variable response to enzyme supplementation is an important reason limiting the widespread acceptance of feed enzymes. The major reasons contributing to these variable responses are discussed. Main features of the next generation of feed enzymes and the various trends that will drive the future use of enzymes are highlighted. The use of feed enzymes in poultry and pig feed formulations is expected to increase in the future and this will be driven by on-going changes in the world animal production. Aquaculture and ruminant industries are emerging markets for exogenous feed enzymes. The article presents some promising patents on feed enzyme technology.

RUMINANT NUTRITION SYMPOSIUM: Acidosis: New insights into the persistent problem1

The Ruminant Nutrition Symposium titled "Acidosis: New insights into the persistent problem" was held at the Joint Annual Meeting of the American Dairy Science Association, American Society of Animal Science, Poultry Science Association, Asociación Mexicana de Producción Animal, Western Section-ASAS, and the Canadian Society of Animal Science in Denver, Colorado, July 11 to 15, 2010. The objective of the symposium was to provide the ruminant nutrition community with new insights and perspectives from recent research findings on acidosis. Under modern production systems, ruminants are fed high-grain diets to maximize their energy intake and productivity. However, feeding highly fermentable diets often causes excess fermentation and results in accumulation of fermentation acids in the rumen, leading to a decrease in feed intake, poor feed efficiency, liver abscesses, and lameness in feedlot cattle or lactating dairy cows. Although our understanding of nutritional factors (i.e., effects of type and processing method of grains and importance of physically effective fiber) affecting rumen pH have increased substantially over the past few decades, rumen acidosis has continued to be a common problem in the ruminant livestock industry. The symposium program was organized to review recent research findings in acidosis with more emphasis on physiological aspects, and provide novel insights into the persistent problem.

Anthelmintic resistance. An overview of the situation in the Nordic countries

Gastrointestinal nematodes in grazing animals cause major production losses and represent an animal welfare problem worldwide. For decades use of anthelmintics has been central in the control programs of these parasites. This intensive use of anthelmintic drugs has resulted in problems with resistance to the anthelmintic drugs available today. Resistance to all classes of broad-spectrum anthelmintics available benzimidazoles (BZ), imidothiazoles-tetrahydropyrines and macrocyclic lactones has been reported [1].The time from introducing a new class of anthelmintic drugs until resistance has been detected seems to be less than 10 years [1]. As time has passed problems of multiresistance to more than one class has occurred as well. Multiresistant Haemonchus contortus has become a major threat to the whole small ruminant industry in part of South Africa and in the South-East of USA [2,3]. At present, resistant nematode populations are detected in all our naturally grazing species; sheep, goats, cattle and horses [1] . In pigs, resistance to pyrantel, levamisole and benzimidazoles in Oesophagostumum spp have been detected [4,5].

Pox outbreaks in Sheep and Goats at Makhdoom (Uttar Pradesh), India: Evidence of Sheeppox Virus Infection in Goats

Sheeppox and goatpox outbreaks occur often in India incurring huge economic loss to the small ruminant industry. This paper describes two sheeppox outbreaks, of which one occurred in an organized sheep breeding farm at Makhdoom (Uttar Pradesh), India, during 2007 and another in goats at the Central Institute of Research on Goats, Makhdoom (Uttar Pradesh), India during 2008. In the first outbreak, a local Muzaffarnagari sheep breed was affected (n=477) with morbidity and mortality rates, respectively, of 100% and 53.9% accompanied by significant productivity losses. In the 2008 outbreaks, a small number of goats were affected without any mortality. The tissue and swabs collected from both the outbreaks were processed and inoculated onto Vero cells, and the causative agent of the outbreaks, capripox virus (CaPV), was isolated. The identity of the virus was confirmed as CaPV based on electron microscopy, experimental pathogenesis in sheep, capripox-specific conventional and real-time PCRs. Sequence analysis of the P32 envelope protein gene revealed that the causative agent of both outbreaks was confirmed as sheeppox virus (SPPV) implying SPPV infection not only in sheep but also goats in India.

Using copper oxide wire particles or sericea lespedeza to prevent peri-parturient gastrointestinal nematode infection in sheep and goats

Gastrointestinal nematodes (GIN) continue to plague the small ruminant industry, especially in parts of the world with warm, humid climates. Alternatives to chemicals are needed for GIN control because of anthelmintic resistance and a desire to reduce chemical residues in meat products. Three experiments using peri-parturient does or ewes addressed the objective: 1) in Arkansas, meat goats were untreated ( n = 20) or fed copper oxide wire particles (COWP; 2 g each) in pelleted sericea lespedeza ( Lespedeza cuneata; n = 22) before kidding while consuming sericea lespedeza hay, 2) in Arkansas, 42 Katahdin ewes were randomly assigned to remain untreated or were fed COWP (2 g each) before lambing within groups fed bermudagrass ( Cynodon dactylon) or sericea lespedeza hay in a 2 × 2 factorial design, 3) in Louisiana, Gulf Coast Native ewes were randomly assigned to remain untreated or were fed COWP (4 g each) in a pelleted ration ( n = 10 each) after lambing began. Fecal egg counts (FEC) and blood packed cell volume (PCV) were determined weekly in all experiments, and coproculture to examine GIN species was conducted in the first two experiments. Haemonchus contortus is typically the predominant GIN in the southeastern U.S., even during cooler months. However, Trichostrongylus spp. was the predominant GIN in Arkansas during these experiments. In all of the experiments, feeding COWP led to a reduction in FEC, but no change in PCV. The sericea lespedeza hay fed to ewes in Experiment 2 was associated with a reduction in FEC compared with ewes fed bermudagrass hay. Kids and lambs from COWP-treated dams in two experiments were lighter than those from untreated dams. Sericea lespedeza aided in the control of GIN infection, and while feeding COWP to peri-parturient ewes and does offered some reduction in GIN infection, body weight of offspring at birth and 60 or 90 days of age may be reduced.

Wheat gluten films prepared at high temperature and low pH decrease degradation by rumen microorganisms

Encapsulated amino acids, vitamins, and other nutrients are gaining popularity in the ruminant feed industry. The purpose of encapsulation is to provide protection from premature digestion in the rumen, making it possible to increase bioavailability of the core ingredient in the small intestine. Encapsulated products are more effective at delivering a targeted amount of a limiting nutrient than the traditional methods of heat or chemically treating protein, which result in an excess supply of other nutrients. The main limitation of feeding encapsulated products is cost. These products are expensive because of the cost of the film forming/encapsulating materials used. Wheat gluten is an inexpensive alternative and has natural film-forming capabilities. Processing factors that influence the extent of degradation in the rumen and subsequent uptake in the post-ruminal digestive tract have not been fully elucidated. The objective of our research was to identify the initial processing conditions under which wheat gluten will provide sufficient protection from microbial degradation in the rumen. Temperature and pH, in particular, have a large effect on the final properties of the film because of their ability to alter the protein structure of the wheat gluten.

Systematic Review of Johne's Disease Vaccination

Johne's disease (JD) is a major health concern for the cattle and small ruminant industries world wide. Vaccination against JD has been in use since 1926, but has been controversial. Our objective was to conduct a systematic review of JD vaccination and do a metaanalysis of the data.

Sericea lespedeza hay as a natural deworming agent against gastrointestinal nematode infection in goats

Infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, is the biggest constraint to profitable goat production in the United States (US). Due to widespread prevalence of anthelmintic resistance in goat GIN, alternative, non-chemical control methodologies are needed to increase profitability of small ruminant industries. A study was designed to test the efficacy of a high condensed tannin (CT) legume, sericea lespedeza [SL, Lespedeza cuneata (Dum.-Cours. G. Don)] against GIN of goats fed in confinement. The goats were given a trickle infection of 500 H. contortus larvae/animal three times per week during the trial to simulate natural infection. Twenty Boer bucks (6–8 months old) were fed bermudagrass [BG, Cynodon dactylon (L.) Pers.] hay plus concentrate for 5 weeks in confinement and then 10 animals were switched to SL hay for an additional 7 weeks. Throughout the trial, feces and blood were collected weekly from individual animals to determine fecal egg count (FEC) and blood packed cell volume (PCV). Fecal cultures were made weekly from pooled samples to determine treatment effects on GIN larval development. All goats were slaughtered at the end of the trial, with adult worms in the abomasum and small intestine of each goat recovered, counted, and identified to species. Feeding SL hay to goats significantly ( P < 0.01) reduced FEC and increased PCV compared with BG hay. In addition, a lower percentage of ova in feces from SL-fed goats developed into infective (L3) larvae. There was a direct effect of SL hay on adult worms, with significantly ( P < 0.01) lower numbers of both abomasal ( H. contortus, Teladorsagia circumcincta) and small intestinal ( Trichostrongylus colubriformis) nematodes compared with goats fed BG hay. Feeding SL hay to goats is an effective means of controlling parasitic nematodes and may be a potential supplement/replacement for chemical anthelmintics.

Sustainable nematode parasite control strategies for ruminant livestock by grazing management and biological control

Internal parasitism constitutes one of the greatest disease problems in grazing livestock worldwide. Control of these parasites is now becoming a serious concern, particularly in the small ruminant industries, due to the widespread and rapid development of resistance to chemotherapy. The broad-spectrum drugs (anthelmintics) used in the control of nematode parasites fall into just three classes viz. the benzimidazoles, imidothiazoles and macrocyclic lactones. Resistance to all three drug classes now occurs in the major nematode parasites of sheep and goats throughout the world. This is largely the result of a more-or-less complete reliance on anthelmintics for worm control. By analogy then, any specific parasite control method may be unsustainable when used in isolation. The more choices and the greater variety of controls used in combination, rather than relying almost solely on anthelmintics, the longer effective worm control can be expected. Grazing management strategies and biological control offer two non-chemical methods of parasite control, which have proven effectiveness. These should form part of integrated nematode parasite control programmes for grazing livestock with the objective of maintaining long-term sustainability.

Domestication of ruminant livestock and the impact of nematode parasites:possible implications for the reindeer industry

In a balanced ecological system, both host and nematode parasite populations are firmly controlled by a complex array of interacting factors. However domestication of livestock has tipped the balance in favour of the parasites. This is due to increasing the proportion of susceptible animals in the herd or flock (lactating females and weaned young animals), increasing stocking rate, increasing productivity demands and decreasing the movement of the animals. In contrast with microbial infections, where multiplication takes place entirely within the host, metazoan parasites have both a parasitic phase and a free-living phase. Every worm present has been separately acquired by the ingestion of free-living stages on pasture. Immunity to nematodes develops slowly, it is labile, and its maintenance is dependent upon a good nutritional state of the animal. Consequently, worm parasites are ubiquitous wherever livestock are kept and they impose a constant and often a high infectious pressure on grazing animals. Nematode infections in grazing livestock are almost always a mixture of species. All have deleterious effects and collectively lead to chronic ill thrift. Economic evaluations repeatedly show that the major losses due to parasites are on animal production, rather than on mortality. This paper focuses on the problems of nematode parasites; problems associated with drug use (anthelmintic resistance, environmental impact) and costs of nematode infections for the common ruminant livestock industries (cattle, sheep, goats), with possible analogies for the semi-domesticated reindeer industry.

Global perspectives on nematode parasite control in ruminant livestock: the need to adopt alternatives to chemotherapy, with emphasis on biological control.

Effective, sustainable control of nematode parasites of grazing livestock is becoming evermore challenging and difficult. This is largely due to two contrasting issues. One is the rapid escalation of resistance to anthelmintic drugs, which is arguably the greatest problem now facing the small ruminant industries worldwide. Secondly, there is the increasing trend towards organic farming, in which there is prohibition of the prophylactic use of all chemical compounds. Livestock producers urgently need non-chemotherapeutic alternatives in parasite control. Researchers have responded to this challenge and a variety of quite different approaches have been the subject of intense investigation in many countries for several decades now. These vary in relation to their stage of development for on-farm use, their utility, and their applicability across the spectrum of grazing livestock enterprises throughout the world. One relatively recent innovation is the biological control approach to nematode parasites. This has now reached the stage of commercialization. This review focuses on these issues and provides an overview of the possible ways in which the biological control of nematode parasites could be employed in grazing ruminant livestock systems worldwide.

Caseous Lymphadenitis in Small Ruminants

Caseous lymphadenitis is a contagious bacterial disease that affects sheep and goats. It is characterized by abscess formation in the skin, internal and external lymph nodes, and internal organs. The causative agent is Corynebacterium pseudotuberculosis. The disease can become endemic in a herd or flock and is difficult to eradicate by virtue of its poor response to therapeutics, its ability to persist in the environment, and the limitations in detecting subclinically affected animals. The disease causes significant economic impact on the small ruminant industry through decreased meat yield, damaged wool and leather, decreased reproductive efficiency, culling of affected animals, and mortality from the internal environment.

The effect of feeding rations containing heat treated rapeseed meal, lupins and beans to lactating dairy cows on milk yield and quality

The UK ruminant industry is currently reliant on soyabean meal and fishmeal as sources of high quality, digestible undegraded protein (DUP). However, there is increasing concern over the sustainability of fish stocks, and the world market price fluctuation and traceability of soya bean meal. There are a number of protein crops which will grow under UK conditions including sweet white lupins, peas, field beans and oilseeds (rapeseed meal and linseed meal). However, these proteins tend to be more rumen degradable than fish meal and soyabean meal (Moss and Givens, 1994). Heat moisture treatment has been shown to be particularly effective in reducing the rumen degradability of protein without reducing intestinal digestibility (Herland, 1996). This experiment was undertaken to determine the effect of feeding moist heat treated rapeseed meal, lupins and beans to dairy cows.

Opportunities for biological control of ruminal methanogenesis

Methane is a major waste product from ruminants, contributing 53% of Australia's total emissions of the gas. Arange of chemical inhibitors of methanogenesis are known to be effective but the real and perceived risks to the environment and health from chemical residues may curtail widespread application of these products in ruminant industries. As with other agricultural industries, future control of unwanted organisms (such as methanogens) is likely to lie with biocontrol agents rather than with chemicals. Opportunities exist for biological reduction of rumen methane emissions using direct means (viruses and bacteriocins specific to methanogens), and indirectly through the elimination of rumen protozoa which symbiotically support some rumen methanogens. The feasibility of these approaches and their current research position are discussed. The most promising work to date is using the common food preservative, nisin (a safe and naturally occurring bacteriocin). When ruminal contents were incubated with nisin in vitro, methane emissions were reduced by 36%.

International approaches to the concept of integrated control of nematode parasites of livestock

Livestock production systems throughtout the world are under severe and sustained pressures. These are diverse and multi-factorial, ranging from the need to redress the oversupply of livestock commodities from the protected industries of the industrialised world, meeting animal welfare expectations, attempts to ease animal-induced land degradation and pollution, and competition with alternative products. As a consequence, funding for research to the ruminant livestock industries has been contracting universally. This applies particularly to research on those diseases of grazing livestock that are not zoonotic, threats to trade, or major “killer” diseases. Gastrointestinal helminths fall outside these priorities. The last decade has witnessed a major contraction throughout the world in the number of research centres and staff involved in applied veterinary parasitology research. This coincides with a time when these livestock industries need the most help. Resistance to anthelmintic drugs amongst the major nematode parasites of sheep and goats has now reached alarming proportions throughout the world and threatens the future viability of continued small ruminant production in many countries. Anthelmintic resistance is also increasing in the important nematode parasites of cattle. Also, this time coincides with the apparent reduction in the discovery and development of entirely new anthelmintic products by the pharmaceutical industry. As a consequence, those remaining researchers and extension personnel who have the responsibility of providing support to the ruminant livestock industry, are showing innovation and lateral thinking in ways to combat the perennial problem of internal parasites in grazing livestock. There are a number of excellent examples of parasite-control schemes, which do not rely entirely on anthelmintic treatment. These are now being supplemented with some exciting novel approaches to dealing with particularly pressing parasite problems. Also there is a move towards the development of true integrated approaches in the control of nematode parasites of livestock, which employ several of these methods when appropriate. This proves that as far as worm control in livestock is concerned, the old adage “necessity is the mother of invention”, holds true.

Anthelmintic resistance

Since the first reports of resistance to the broad spectrum anthelmintics were made some three decades ago, this phenomenon has changed from being considered merely as a parasitological curiosity to a state of industry crisis in certain livestock sectors. This extreme situation exists with the small ruminant industry of the tropical/sub-tropical region of southern Latin America where resistance to the entire broad spectrum anthelmintic arsenal now occurs. In contrast, the cattle industry does not appear to be threatened — or so it seems. Although field reports of resistance have been made to the range of broad spectrum anthelmintics in nematode parasites of cattle, it appears that the evolution of resistance in cattle parasites is not as dramatic as for sheep worms. However, one cannot remain confident that this state of affairs will remain static. Concern is shared amongst parasitologists that we have not looked closely enough. In regions of the world where internal parasites are considered a problem in cattle and drenching occurs frequently, no widespread surveys have been carried out. It appears that because of the very high costs and risks associated with taking a new active drug down the development track to marketing, that the pharmaceutical industry has, in general, turned away from this activity. By implication, the international small ruminant industry is too small for these companies to make the necessary investment. This begs two questions: What is the fate of the sheep (and goat) industries in those parts of the world where resistance is rampant and immediate ameliorative parasite control options are required? What will be the response if significant resistance is found in cattle parasites? There is a body of opinion which suggests that if resistance becomes an issue in the control of cattle parasites then the pharmaceutical industry will find it commercially attractive to re-enter the anthelmintic discovery and development business. This is based on the simple commercial fact that fby ar the greatest anthelmintic sales are associated with the cattle industry. However, this market is specific and sectoral, with by far the greatest sales in North America and Western Europe, where the prevalence of resistance is likely to be low and remain so, more-or-less indefinitely. So the chances of the above scenario occurring must be considered low. Remarkable developments have recently occurred in non-chemotherapeutic parasite control options, for example worm vaccines, host selection and biological control. Also, there seems to be greater acceptance of various grazing management practices designed to reduce the frequency of anthelmintic treatment. However, they collectively cannot be expected to offer immediate salvation to farmers now faced with chemotherapeutic failure to control nematode parasites in their flocks. The future for these farmers must be considered bleak, because compounded with these problems are the poor commodity prices for sheep and goat meat and fibre, resulting in relentless reductions in funding for research to support these industries. Perhaps the major social issues associated with re-structuring and possibly abandonment of sheep and goat farming in affected areas may precipitate action? As veterinary parasitologists, who in general have an interest and expertise in parasite control, we must promote the importance of the problem of anthelmintic resistance and ways to tackle it.

Rumen physiology: the key to understanding the conversion of plants into animal products

Ruminants have always provided meat, hides and fibre for human use, and since the development of agriculture with its associated domestication of herding ruminants, they have also provided milk and draught power. Sound interpretation of the observations of animal behaviour and performance made by the early hunters and stockmen was not possible until knowledge of physiology began to accumulate in the 18th and 19th centuries. The development of new methods about 50 years ago led to the modern era of ruminant physiology, a flowering of research which has continued to the present day. Rumen physiology is intrinsically interesting but it also has utility because it is fundamental to the understanding of ruminant nutrition. Research must continue, particularly in the areas of microbial ecology and particle kinetics, if the ruminant industries are to respond adequately to the need to produce more food for humans from non-arable land and by-products, to increase product quality, to tailor products to market requirements and, in doing so, reduce their environmental impact

Effects of Maturity on Chemical Composition and Digestibility of Bird Resistant Sorghum Plants When Fed to Sheep as Silages

ALTHOUGH corn has provided the base crop both as a grain and silage source for the ruminant livestock industry in the midwest, diseases and severe predations by birds in some areas have forced a search for substitute crops of similar nutritive value. Grain sorghums offer yield potentials similar to corn, possibly greater drought resistance and greater latitude of soil fertility. High grain producing varieties of sorghums have recently been developed which are resistant to bird damage at least in the milk and dough stages due to high tannin content in the seed pericarp (Fuller, Potter and Brown, 1966; Harris, Johnson and Stacy, 1964). Recent studies at this research center 4 have shown that 100% of a non bird resistant variety was destroyed while five bird resistant varieties of sorghum were undamaged. Bird resistant sorghums have been fed to cattle with no apparent problems (Davies and Stallcup, 1966; Merwine, 1961). Fox et al. (1970) found, however, that the net energy value and digestibilities of AKS 614 bird resistant sorghum were considerably less than those values for corn, both when fed as a grain and a silage to beef cattle. They found that the sorghum grain at late maturity was highly resistant to digestion unless the hull was broken by grinding.