Early harvest testing suggests corn silage may be a higher-risk commodity across Canada, says Alltech. Barley may have a greater prevalence of mycotoxins, and in higher concentrations, than wheat. At press time, Alltech didn’t have results on corn grain, but reminded producers that corn is often at risk.

Mycotoxins, produced by moulds and fungi, can influence feed quality and subsequent animal health and performance. Difficult to detect, they can damage animal health before producers realize they’re present. Alltech states that they are becoming more prevalent and problematic, pegging 95 per cent of crops today as contaminated with at least one mycotoxin.

“Canada has experienced a change in weather patterns from last year, particularly of note the greater rainfall across the Prairies,” said Dr. Alexandra Weaver, global technical support for Alltech, in the release. “As a result, there appears to be greater mycotoxin risk in the Western Canada 2024 harvest than last year. We’ve also noticed continued risk from deoxynivalenol and zearalenone in Eastern Canada, which can impact animal health and performance.”

Other early results from the Alltech 2024 Canadian Harvest Analysis include:

• Quebec: Ninety per cent of corn silage samples have tested positive for zearalenone (ZEA), with maximum levels reaching 1,369 ppb. Deoxynivalenol (DON) is found in 68 per cent of samples, peaking at 6,782 ppb. T2-HT2 toxins are less common (25 per cent) but still pose a risk.
• Ontario: Wheat samples show a 63 per cent prevalence of DON and 45 per cent for ZEA, with moderate risk levels on average. Corn samples have tested positive for DON with a maximum of over four ppm, with levels most problematic for swine, young and breeding animals.
• Manitoba: Fifty-nine per cent of barley samples contain DON, with maximum levels up to 3,700 ppb. Corn silage shows a 100 per cent prevalence of ZEA, peaking at 1,118 ppb, and a 64 per cent prevalence of DON, with a max of 3,200 ppb.
• Saskatchewan: Eighty-eight per cent of barley silage samples contain ZEA, and 30 per cent have DON. T2-HT2 toxins also have a presence, at about 43 per cent occurrence. All three mycotoxins average lower risk, but with potential for higher risk levels in some samples.
• Alberta: Barley silage shows lower risks, with ZEA detected in about 22 per cent of samples. Corn silage shows a greater risk from ZEA, in 100 per cent of tested samples and a maximum detection of over 700 ppb. Corn silage also shows a presence for DON and T2-HT2 toxins.
• British Columbia: Corn silage samples show a presence of multiple fusarium mycotoxins, including DON, T2-HT2 toxins, ZEA and emerging mycotoxins. On average, DON, T2-HT2 toxins and ZEA have been detected at lower-to-moderate risk for dairy cows. However, some silage samples have shown high risk levels of DON and T2-HT2 toxins.

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The common spoilage organisms affecting sweet clover are soilborne. There are a variety of bacteria and moulds that grow in sweet clover when it is baled or put up as silage. Damp, unfavourable conditions, or failure to pack silage properly to exclude air promote spoilage organism growth. Weathered, large round bales, particularly the outer portions, usually contain the highest concentrations of dicoumarol.

The sweet clover plant is high in the compound coumarin, which is converted to dicoumarol if the plant is spoiled or damaged. Dicoumarol is a potent vitamin K antagonist and anticoagulant preventing normal blood clotting resulting in hemorrhages and associated symptoms. Vitamin K is needed as part of the blood clotting process. Dicoumarol concentrations of 20 to 30 mg/kg of hay ingested throughout several weeks are usually required to cause poisoning in cattle. The toxic agent crosses the placenta in pregnant animals, and newborn animals may be affected at birth. All species of animals studied are susceptible, but instances of poisoning involve cattle and, to a limited extent, sheep, pigs, and horses.

When vitamin K is inhibited, cattle can essentially bleed to death internally. Warfarin, which is found in rat, gopher and ground squirrel poisons, works in much the same way.

Symptoms include stiffness, lameness, dull attitude and hematomas or blood clots beneath the skin, particularly around the hips, brisket and neck. Mucous membranes can turn pale, indicating anemia. The toxin also can cause reproductive problems at sub-clinical levels. Poisoning occurs less often in silage than in hay and infrequently in pastured animals. The time between consumption of toxic sweet clover and appearance of clinical disease varies greatly and depends on the dicoumarol content of the particular sweet clover variety being fed, age of the animals and amount of feed consumed.

If the dicoumarol content of the ration is low or variable, animals may consume it for months before signs of disease appear. In affected animals, the first signs may be stiffness and lameness due to bleeding into the muscles and joints. It is not uncommon for producers to first become aware that sweet clover toxicity is an issue after cattle are dehorned, castrated, or at calving time when, unfortunately, animals succumb to hemorrhage.

This biennial plant has really expressed itself this year, and is abundant, due to the excellent moisture conditions in some areas. As a grazing resource, sweet clover can be excellent feed. Research from North Dakota State University has documented yearlings gaining over two pounds per head per day grazing sweet clover pasture.

Producers need to be very cautious when feeding sweet clover that is spoiled or mouldy. Here are some preventative steps:

• Test suspect hay for dicoumarol. Your veterinarian should be consulted.
• Plant only low-coumarin-content sweet clover (Melilotus dentata). Avoid contamination of pastures or hayfield with yellow (M. officinalis) or white (M. albus) sweet clovers, which have high levels of coumarin.
• Sweet clover is a legume so it can also cause bloat. Most of the time, sweet clover is a part of a diversity of grasses, sedges, legumes and forbs on rangeland or pasture and doesn’t result in bloat (University of Nebraska, Lincoln). Providing a supplement with an ionophore such as Rumensin as well as the use of poloxalene (Bloatguard) several days before turning cattle into pasture with legumes can help reduce the risk of bloat.
• Stack or bale sweet clover only when it is well cured and dry. Sweet clover stems can be quite large and hard to dry. Tight, dense bales that are damp can make the problem worse as mould formation will be greater at the core of the bale.
• If you suspect hay could be toxic, feed it for seven to 10 days, then replace it with alfalfa or other forage for an equal period of time.
• Do not feed sweet clover for at least three weeks before or during the calving period, or before any surgical procedures like castration or dehorning.

Unfortunately, it doesn’t take much dicou­marol to cause a problem. Hay containing greater than 10 parts per million of dicoumarol should be fed with caution. All cattle are susceptible, but younger cattle seem to be more susceptible than mature cows. Pregnant cows may abort or give birth to stillborn calves if they are consuming mouldy sweet clover hay.

Intravenous administration of whole blood is the best and most effective treatment. This may be difficult in large animals, because effective dosages range from two to 10 litres of fresh blood per 1,000 lbs. (450 kg) body weight. Care should be taken to ensure that donor animals are not receiving sweet clover feed. All clinically affected animals should receive a transfusion, which can be repeated if necessary. In addition, all severely affected animals should receive parenteral administration of synthetic vitamin K1 (phytonadione). Although more costly, vitamin K1 is more effective than K3 (menadione). Coagulation can be restored in about 24 hours.

Sweet clover is an opportunistic plant that takes advantage of good growing conditions when available. In grazing situations, clover is a good feed resource. In the feed yard or silage pit, be careful.

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Vomitoxins such as deoxynivalenol (DON) are produced by fungi that infect cereal species. Grain contaminated with DON can’t be consumed by people, and can only be safely fed to livestock if levels are low. DON is also resistant to heat treatment and regular processing methods, making it difficult to deal with.

“Vomitoxin, or DON, has been a serious issue for corn and other cereal crops for a long time,” says Agriculture and Agri-Food Canada (AAFC) scientist Dr. Ting Zhou in a release. “With no satisfactory solutions, we decided to try a new and creative approach.”

AAFC researchers found a new soil bacterial species that produces two enzymes that convert DON to a non-toxic form. The bacteria have several characteristics that make them suitable to industrial application, such as the fact that they don’t need DON as a food source to grow. They can also grow at lower temperatures and in the presence of oxygen. That means the bacteria, or the enzymes, may be used to reduce contamination in grain.

The next step for researchers is to partner with industry to develop commercial products containing microbes and enzymes that can detoxify DON-contaminated grain.

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Ontario’s Agricorp says that most affected farmers are in southwestern and western Ontario, Farms.com reports. Tvo.org reported vomixtoxin levels as high as 25 parts per million, which is 25 times higher than the allowable limit for pig feed.

Provincial and federal governments are offering to cover part of eligible farmers’ expenses for testing DON levels. Both governments also pledged to support new projects to process or market DON-infected corn and to work with the Grain Farmers of Ontario on ways to reduce DON’s impact by, for example, finding ways to temporarily store the corn to improve its quality.

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For cattle feeders lower feed prices are welcome, particularly after the negative margins of the last 12 months or so. However, there are a number of challenges when it comes to incorporating off-grade feed grains into a cattle feeding program. These challenges fall under three broad categories including issues with reduced feeding value; feeding management; and with mycotoxins.

From a feeding perspective, the concern with light-weight grain is that the kernel has not filled and thus its starch/energy content is reduced. For example, normal feed wheat has a test weight of 60 pounds per bushel. In terms of net energy content, wheat has an average value of 2.2 and 1.59 Mcal per kilogram of dry matter (DM) for maintenance (NEm) and gain (NEg), respectively. Its NEg value is approximately eight per cent higher than that of barley and two per cent lower than corn grain. Feed wheat typically weighs in at less than 60 pounds (i.e. 50 to 56 pounds or less) with an energy value similar to or slightly higher than barley grain, depending on the reason for downgrading. Most feedlots consider normal barley to weigh in at 48 pounds or more. While lightweight barley is typically purchased at a discount relative to the value of normal barley, performance is not adversely affected, until bushel weight drops below 44 pounds.

Similar comments apply to corn. For example, research at the University of Nebraska has shown that there was no difference in performance of cattle fed 46-pound versus 56-pound corn.

Feed wheat offers particular challenges when it comes to feeding management. At 60 to 65 per cent starch, wheat is intermediate to barley (55 to 60 per cent) and corn (65 to 70 per cent). However, of the three, wheat has the fastest rate of rumen starch fermentation. This characteristic has important implications for feeding management as its high starch content and rapid fermentation can predispose cattle to rumen acidosis (i.e. gain overload).

Too much wheat, too quickly will result in rapid production and accumulation of acid in the rumen. This drops rumen pH and leads to acidosis which can range in severity from acute to sub-acute. Symptoms of sub-acute acidosis include erratic feed intake, reduced gains, poor conversions, lameness and liver abscesses. To minimize these issues, many nutritionists recommend blending wheat into the ration and have an upper limit on the amount fed, typically 50 per cent of the grain portion of the ration.

In a finishing diet, this means a maximum of 40 to 45 per cent wheat (DM basis). Wheat should also be introduced in steps, replacing barley (or corn) at 10 per cent increments (DM basis). At each step, cattle should be given two to three days to adapt, after which, if they are eating normally, it is safe to move to the next step. Properly adapted wheat-fed cattle will have superior feed conversions relative to barley-fed cattle, and if wheat is priced competitively, lower feed costs.

From the phone calls that I have received, the biggest issue with this year’s grain crop is mycotoxins, particularly with fusarium-contaminated grain. Fusarium infection of wheat results in shrunken, off-colour kernels, known as fusarium damaged kernels (FDK) or more commonly “tombstones.” In corn, it is sometimes referred to as pink ear rot. Fusarium-damaged kernels can be contaminated with a number of mycotoxins including deoxynivalenol (DON), nivalenol, T-2 and HT-2 toxins. While space limits the discussion of these mycotoxins, producers should be aware that toxins such as T-2 and HT-2 are extremely toxic in very small amounts. DON, while not as toxic to cattle as T-2 or HT-2 toxins, will likely be the most common mycotoxin encountered in fusarium-contaminated grain. Reduced feed intake, poor growth and immune function are the major issues one can encounter when feeding DON-contaminated grain.

Feeding mouldy grain, particularly that infected with fusarium, is tricky as the presence of the fungus does not necessarily mean mycotoxins are present, and when mycotoxins are present, it is also possible to have more than one type contaminating the grain. As well, while there are guidelines as to the maximum inclusion level of these various mycotoxins in the ration, there is no clear consensus as to what level can be safely fed. For all these reasons, if you are planning on using fusarium-contaminated grain, you would be well advised to have representative samples tested for mycotoxins by a qualified laboratory. As well, working with a nutritionist experienced with these and other off-quality grains will be critical to feeding cattle safely and efficiently.

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The fusarium family of fungi infects the seed of small-grain crops, corn and other grasses and causes a whitish-pinkish-orangish mould to grow on plants, producing a witch’s brew of mycotoxins, namely the Type B tricothecenes (T-2 toxins and deoxynivalenol, commonly called DON or vomitoxin), zearalenone and fumonisin. Claviceps purpurea is the fungus responsible for causing the black-purple ergot bodies in grain and grass heads that release toxic alkaloids.

Alltech mycotoxin expert Dr. Max Hawkins says DON has been the most prevalent mycotoxin so far in new-crop corn silage samples from Canada and right across North America for that matter. DON is also the No. 1 mycotoxin showing up in spring wheat, barley and triticale samples from Canada. There have been some high occurrences of ergot, but they tend to be somewhat more regionalized and particularly concerning in some samples of spring wheat from the southern prairies and U.S. northern plains.

Alltech’s 2016 harvest report on 100 total-mixed-ration samples from across the U.S. analyzed at the company’s ISO-accredited lab at Winchester, Kentucky, shows that less than two per cent of the samples are clean or contain only one mycotoxin. Nearly 18 per cent of the samples contain six to seven mycotoxins, 42 per cent contain four to five, and 35 per cent contain two or three.

As Hawkins says, mycotoxin issues aren’t limited to growing regions with contaminated crops. Mycotoxins move around just as quickly as grain travels down the road or across the rails.

Grass pastures, cereal swaths and standing corn for winter grazing, cured and ensiled grass and cereal forages, crop co-products (straw, distillers grains, grain screenings, oilseed meals) and commercial feeds — in short, pretty much any feedstuffs that comprise beef cattle rations are potential sources of mycotoxins. This can create quite a challenge given that the organisms can persist from pasture to wintering rations. The risk to livestock depends on the level of contamination in the soil, the harvesting date, feed type, source of purchased feeds, and even the age and breed of cattle.

Ruminants do have an advantage over monogastrics in that rumen microbes are capable of breaking down many mycotoxins to reduce and even void the toxic effects, depending on the mycotoxin.

However, some mycotoxins play off others to compound toxic effects. While mycotoxins present in single feed ingredients may be under the established tolerance level for beef cattle, combining the ingredients could be toxic. A typical example in cattle rations is DON and fusaric acid. On their own, neither may be at a level of concern for beef cattle. Together, the risk equivalent factor (REQ) is 187.

REQ is Alltech’s calculation of risk for all of the mycotoxin present, not just the one or two that are highest, Hawkins explains. A REQ at 187 is high risk for mature cattle and higher risk yet for young and growing cattle.

Combinations of fungal moulds can also wreak havoc in stored feeds. For example, the mycotoxins produced by Penicillium fungi (blue to green mould), are efficiently broken down in the rumen and generally don’t cause problems for beef cattle unless they are present at very high levels, although they have been known to cause false positives for antibiotic residues in milk. When both Penicillium and fusarium are present in field crops, the overall mycotoxin levels in stored feeds tends to be high.

Mycotoxin poisoning at its worst in beef cattle can cause abortion storms and scours outbreaks. Usually, the symptoms of a steady low level of mycotoxins in feed are subtle, nibbling away at overall health and performance. Loose manure and a bloaty appearance are general signs. Feeders might become suspicious if the rate of gain isn’t up to par. Cow-calf operators might see lower pregnancy rates or a decline in body condition.

Possible warning signs of DON toxicity include diarrhea, reduced feed intake and reduced weight gain. T-2 toxin manifests as gastroenteritis (inflammation of the digestive tract), sometimes with intestinal hemorrhage and bloody manure. Zearalenone stimulates estrogen production and leads to reproductive problems that could include infertility, abortions, vaginitis, vaginal prolapse and enlarged mammary glands in young heifers. Fusaric acid may be the reason behind swelling of the lower legs, low blood pressure, lethargy and feed refusal.

Feed refusal and weight loss are typical signs of ergot alkaloids in the feed. Ergotism in cattle most often constricts blood flow to the extremities, resulting in lameness and sloughing of ears, tails and even hooves. Some animals may show signs of the nervous form, such as excitability or convulsions. The estrogen in ergot bodies can cause abortions or disrupt the reproductive cycle.

Alltech’s mycotoxin strategy

Mycotoxins are most often associated with wet conditions at certain stages of crop growth. Some like it cool, others need heat to germinate. Fusarium is a heat-loving pathogen that can affect drought-stressed crops as well. This was the case during the widespread drought of 2012 in the U.S. when Alltech brought together a team to develop a strategy for managing contaminated feeds. The resulting mycotoxin management program was launched in March 2013.

It has since been put into operation at all of the company’s feed manufacturing and premix facilities.

The first step is a Mycotoxin 37+ analysis which can detect more than 37 mycotoxins in raw feed ingredients, forages and mixed rations. Based on the results, the team assesses the risk to your animals and provides recommendations tailored to your operation.

Alltech’s regional representatives will visit farms to take strategic samples. “It’s easy to get a sample, but challenging to get a good sample representative of all feedstuffs in one pound of material,” explains Hawkins.

Not all calls are from producers experiencing problems. Some call because they’ve heard of issues in their area and want have an analysis done before any problems appear.

Alltech’s MIKO program evaluates feed and forage management using a systematic mycotoxin hazard analysis based on established HACCP principles for quality control. It begins with a hazard analysis, determines critical control points, establishes critical limits, and then establishes monitoring procedures, corrective actions, checking procedures and the record-keeping system.

“From the results of all of the samples we receive, we create a database and issue full reports, starting with the harvest report, then again in late winter or early spring on how storage is affecting feeds, and at close-out in summer to evaluate the full effect over time from field through feeding. Then it’s time to clean things up and start again with the new crop,” Hawkins says.

The reports are available from your nearest Alltech representative, the mycotoxin hotline at 866-322-3484, the Calgary office at 403-735-3281, or the Guelph office at 519-763-333. For more visit knowmycotoxins.com.

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Importers of corn — organic or otherwise — from India, starting immediately, first must sample the corn, upon arrival in Canada and provide test results to the Canadian Food Inspection Agency.

The sampling must be done immediately after arrival at the Canadian destination, CFIA said in a release Tuesday, because mould can grow and produce aflatoxins during shipping. Sampling and analysis conducted prior to shipping will not be accepted.

Shipments will only be released with an original certificate of analysis from an accredited lab showing the shipment comes in below the 20 parts per billion (ppb) level, CFIA said.

Seen mainly in imports of food and feeds from tropical and sub-tropical regions, aflatoxins are toxic byproducts of mould growth and are considered a potent carcinogen.

Aflatoxin contamination, at sufficient levels in affected livestock, can limit immune function, compromise resistance to infection and reduce animal performance. Consumed at higher levels, doses of aflatoxins can be fatal.

Canada’s Feeds Regulations limit aflatoxin levels in imports of corn or other feed ingredients to 20 ppb and prohibit corn deemed to be musty, mouldy or damaged from heat or any other cause that would render the feed unfit or unsafe for feeding.

CFIA recommended importers, buyers, feed millers and livestock producers ask for further information from their suppliers on the sources of any corn and contaminant specifications on any ingredients they buy.

USDA’s Foreign Agricultural Service (FAS) staff at the end of April projected India’s total 2014-15 corn exports to come in at about 1.5 million tonnes, down from 3.9 million in 2013-14. — AGCanada.com Network

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Most of the time when there’s a poor pregnancy rate in a herd we suspect infectious causes like trichomoniasis, campylobacteriosis (“vibrio”), lepto, IBR or BVD, but there may be non-infectious causes. Pregnancy may be lost within the first week after conception — or at any stage of gestation.

Late pregnancy loss is visible; you may find the aborted fetus or a cow with placental membranes hanging from the vulva, but with early pregnancy loss you may have no indication, says Dr. Barry Blakley, a toxicologist at Western College of Veterinary Medicine, University of Saskatchewan. And if cows are pregnancy-tested early, a few that were determined pregnant will lose their fetus before calving time.

Blakley says there are four basic causes of loss: genetics, infections, toxins and nutritional deficiencies.

Losses due to genetic causes are nature’s way of weeding out defective offspring that cannot survive. These include defects in DNA that terminate the conceptus very early on, as well as some abortions and stillbirths.

Stress is another factor that is often overlooked. There are many kinds of stress, including nutritional deficiencies, environmental stress (heat, cold, bad weather), systemic disease, etc., that make conditions less than optimum for continuing the pregnancy. Reproduction is a luxury; if the cow is in poor body condition, ill or otherwise stressed, she will either not become pregnant, or may lose the calf, says Blakley. She must first be healthy herself to have a healthy pregnancy.

Dr. Ahmed Tibary, professor of theriogenology, department of veterinary clinical sciences, Washington State University, says pregnancy loss should be considered a possibility whenever there’s a longer-than-average calving season, or a higher-than-usual number of late calvers. Cows that settled late may have bred early but lost their pregnancies and rebred on a later cycle.

Early pregnancy loss

Causes of early loss include alterations in the egg itself, and in the fertilizing semen. “Researchers are looking at possible defects in semen and the effect of genetics on quality of the embryo. In some situations the bull-cow combination (genetically) may lead to increased early embryonic loss,” he says.

“About five to eight per cent of pregnancy losses in beef cattle (of pregnancies that continue beyond 21 days) are lost in the first 42 days. Rapid weight loss in the cow, or other stress such as transportation in early pregnancy can lead to losses. The biggest factors include sudden change in nutrition, environmental stresses like severe cold, or heat. Stressful conditions may cause hormonal disturbances. Moving cattle, particularly in the first 42 days of pregnancy, can be a factor, especially if it involves a lot of stress,” Tibary says. A long truck haul, gathering cattle swiftly to get them away from an approaching wildfire, or cattle being continually harassed by wolves are examples of stress that may lead to pregnancy loss.

Toxic causes of pregnancy loss

Some toxicants affect the fetus — including lupine, hemlock, locoweed, pine needles, ergot alkaloids, certain moulds, etc. For instance, pine needle abortion causes loss in late pregnancy when cows consume Ponderosa pine needles. The greatest risk is when cows consume pine needles for three days or more, and have a high level of toxicant — which constricts blood vessels in the placenta, hindering supply of oxygen and nutrients to the fetus, killing it. The toxicant also increases uterine contractions that expel the fetus.

“Mycotoxins are common causes of pregnancy loss,” says Blakley. “These are metabolites produced by fungi. Zearalenone is one that produces estrogenic effects and infertility,” he says.

“T-2 toxin, dioxynivalenol (also known as vomitoxin or DON), etc., affect rapidly dividing cells — the embryo or fetus — causing embryonic death or abortion. There are at least half a dozen mycotoxins that affect rapidly dividing cells or affect hormones in the animal. They may cause abortions or deformities, or failure of the conceptus to implant in the uterus,” explains Blakley.

Another toxic concern is ergot. “This mycotoxin is a mixture of several alkaloids that can have adverse effects on the animal. In Canada we are seeing more of this problem with changing growth conditions, moisture, temperature and weather,” he says.

“Some of these problems are increasing because of the way farmers manage their crops. No-till farming is becoming more widespread, and if farmers don’t till the fields, the fungus stays on top and spreads. If surface material is tilled into the ground, then the bugs and microbes eat the fungi and get rid of it,” says Blakley.

“Harmful fungi and mycotoxins can also develop in moist areas like ditches and then spread into the grain fields and affect various grasses. If farmers don’t till their fields properly or don’t till them at all, the fields are more heavily contaminated and then the crops are more contaminated,” he says.

“Ergot doesn’t affect the fetus in terms of deformities, but can affect blood supply to the uterus (which could lead to death of the fetus) and also causes band contractions on the uterus, which might expel the fetus.”

“Consumption of certain metals like lead can cause problems including abortions. In the area where we are, there are many oil industry chemicals, and some of these can cause abortion due to organ damage. Certain hormones build up or don’t build up, because of this damage, or may be altered by impaired metabolism, or it may allow for buildup of other toxic chemicals which would otherwise be eliminated by the body.” If the liver isn’t functioning properly it can’t break down and eliminate toxins.

“And in some cases these chemicals actually cause the liver to break them down more quickly and this causes lower levels of certain hormones like progesterone. Therefore the cow can’t maintain the pregnancy,” he says.

“Occasionally certain moulds enter the bloodstream and cause what we call a mycotic abortion. Cattle may also inhale spores from mould and get a fungal pneumonia — which stresses the animal,” he says.

Some plants contain nitrates under certain conditions, and nitrate poisoning can cause fetal death. “Another concern is fertilizers that contain nitrates. Cattle may eat the fertilizer or drink contaminated water. There may not be enough to kill the cow, but enough to affect the fetus. The fetus is much more susceptible to nitrate poisoning than the cow,” Blakley explains.

“Some plants accumulate cyanide which can cause fetal deformities and abortion —though often it kills the cow. Wilted/frosted cherry or chokecherry leaves cause a lot of problems. In Canada we also have a problem with arrowgrass,” he says.

Problems can also be caused by plants that accumulate selenium (since too much selenium is toxic), or plants that contain harmful alkaloids. “The alkaloids cause liver damage, and then the cow can’t maintain the pregnancy,” he says.

“A major concern in certain areas of the world is poor-quality water. It may have high levels of sulphate, which interferes with absorption of copper, etc.” This creates a deficiency in the animal even if soils and feeds contain adequate amounts of copper.

Nutritional stress

“Certain parts of North America are deficient in copper and/or selenium,” says Blakley. “If the animals aren’t getting enough of those important trace minerals they will have reproductive problems. I’ve seen some herds where the reproduction was poor, and after supplementation with copper the reproduction rate returned to normal,” he says.

“Our No. 1 problem in Canada in winter is associated with cattle eating poor-quality feed. The vitamins that were at high levels in forage during summer — particularly vitamins A and E — drop dramatically after feed is stored for a long time during winter. These vitamins are necessary for placental and fetal development. We encounter many vitamin A and E deficiencies in stored feeds. In milder climates this isn’t a problem because there’s green feed nearly year-round. But in our region, starting in October there is almost no green feed available and it may snow under; cattle must eat cut forage,” says Blakley.

“Properly feeding your animals is the best way to prevent pregnancy loss in most situations. Certain genetic problems might be an issue in purebred herds, but under normal conditions with crossbred cattle these would not occur because the defective genes would not be expressed,” he says. Most of these defects have to be inherited from each parent.

Loss due to twins

When a cow conceives twins, there may be twin reduction in early gestation. If a cow carries a twin in each horn of the uterus, the risk for loss is less than when twins are carried in the same horn. Sometimes the cow loses both, and sometimes just one. The producer may find only one calf, but if it’s a heifer freemartin, you know there had to be a twin bull calf present earlier.

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Mycotoxin contaminated feed is not a new issue. However, if we use the last few growing seasons as a yardstick, it appears that the extent of the problem is increasing, particularly for Central and Western Canada. The re-emergence of this issue has been attributed to a number of factors including favourable environmental conditions in the spring and the emergence of more aggressive fungal strains contaminating today’s crops. In the August 2014 issue of Canadian Cattlemen, Dr. Reynold Bergen addressed concerns with ergot. In this column, I will focus on fusarium contamination of wheat and other cereals and the implications for your feeding program.

Fusarium infection of wheat, barley and corn results in a plant disease known as fusarium head blight (FHB). This disease of cereals has been established in Central Canada for several decades and is slowly moving westward. This fall, for example, there are a numerous reports throughout Manitoba and Saskatchewan of FHB contamination of winter wheat, durum and Hard Red Spring wheat. In cereals such as wheat, FHB targets the seed head and results in shrunken, off-colour kernels, known as fusarium-damaged kernels (FDK) or more commonly “tombstones.” In corn it is sometimes referred to as pink ear rot. For the grain producer, crop yield, quality and end use can be negatively affected. For livestock producers, the issue is mycotoxin contamination.

Fusarium-damaged kernels can be contaminated with a number of mycotoxins that collectively are called the trichothecenes. Included in this group are deoxynivalenol (DON), nivalenol, T-2 and HT-2 toxins. The specific mycotoxin or combination of mycotoxins found in contaminated grain depends on the fusarium species that infected the plant. For example, infection by fusarium graminearum will result in the production of DON as well as a number of DON-like derivatives. Under certain conditions, it can also produce T-2 toxin.

Toxins such as T-2 and HT-2 are potent protein inhibitors whose ingestion at levels as low as one part per million (ppm) can result in issues with reduced feed intake, poor growth, ulceration and hemorrhaging of the digestive tract, and even death. Canadian Food Inspection Agency (CFIA) guidelines for cattle limit the intake of HT-2 toxin to 0.1 ppm while the recommended tolerance level for T-2 toxin is less than one ppm (DM basis).

Deoxynivalenol, while not as potent as T-2 or HT-2 toxin, is the most common mycotoxin encountered in fusarium-contaminated grain. Deoxynivalenol is commonly called vomitoxin due to the fact that pigs exhibit severe feed refusal and vomiting at very low levels of intake. Fortunately, cattle are less sensitive, likely due to degradation of DON by rumen bacteria. Reduced feed intake and growth and poor immune function are the major issues associated with feeding DON-contaminated grain to cattle. The upper dietary inclusion limit for DON is not as clear-cut as it is with other mycotoxins. The CFIA guideline for DON in the diet of beef cattle is a maximum of five ppm. For pregnant heifers or cows, this is a reasonable guideline. However, for growing and finishing cattle, it may be on the low side. A Manitoba Agriculture factsheet from the 1990s summarized a number of DON-related research trials which demonstrated that DON levels at nine ppm in backgrounding diets and as high as 18 ppm in finishing diets did not negatively influence growth, feed intake or feed efficiency.

One issue to consider when feeding DON-contaminated grain is that the presence of DON can be a warning sign that other mycotoxins are also present. For example, I have seen test results from 2014 wheat samples that showed DON at 2.5 ppm and HT-2 toxin at 1.3 ppm. Similarly a wheat screening sample containing 11 ppm DON had a combined total of 2.5 ppm for HT-2 and T-2 toxins. Not a lot is known about the combined effects of these mycotoxins, in some cases they may act in a synergistic fashion increasing the negative effects of one or more of these mycotoxins. In such situations, caution is advised, even if one is blending the contaminated grain to “safe” levels.

There are a several laboratories that offer testing services for mycotoxins in grain and forage samples. If you suspect issues, have your feed tested prior to purchase and/or feeding. For larger operations receiving grain on a regular basis, work with your nutritionist to set up a purchasing protocol that sets limits to the level of ergot or fusarium contamination that you will accept.

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