September 6, 2013 15:21
It may be hard to believe with the current warm temperatures but the first fall frost is lingering. After a first frost, there are concerns about nitrates in forage and other livestock feeds. So what are nitrates anyway, where do they come from and why can they be a concern in a feeding program?
Plant roots take up nitrogen from the soil in the form of nitrate (NO3). The nitrate is transported into the leaves where it is converted into protein. Immature plants usually contain more nitrate as they are still growing rapidly. Annual forage crops like oats and millet also normally contain more nitrates compared to perennial forages. Alfalfas, vetches, trefoils, peas and clovers generally do not accumulate nitrates. Under normal growing conditions, nitrates are continuously taken up and converted to protein to fuel plant growth and seed production.
Nitrates can accumulate in a plant following a sudden interruption of growth such as after a frost. The root system is often not affected by a fall frost and continues taking up nutrients from the soil which includes nitrates. As nitrates are being pumped into the plant, the aboveground tissue is not able to process those nutrients and hence nitrates can start to accumulate in stems and leaves. The highest accumulation typically occurs two to three days following a frost. Nitrates will decrease 10 to 14 days after the injury if the plant was not killed and is able to resume growth. If a plant is killed during a frost, the nitrates have no place to go and will remain in the plant tissue. To conserve forage quality it is best to harvest the forage crop within one day of damage. Forage should be tested to know how much nitrates it contains and to be able to adjust the feeding plan accordingly.
The nitrates themselves are not toxic to livestock. However, in ruminants such as cattle, sheep and goats, the rumen bacteria convert nitrate to nitrite (NO2). Nitrite is then converted to ammonia. Nitrate poisoning occurs when the conversion of nitrate to nitrite exceeds the animals’ capacity to convert nitrite to ammonia. Nitrite causes toxicity by reducing the capability of blood to carry oxygen which leads to internal suffocation of the animal. Sub-lethal doses may result in loss of appetite, reduced milk production, slow growth, and abortion.
For more information please contact me at the Watrous Ministry of Agriculture office 306 946-3219, call the Agriculture Knowledge Centre at 1-866-457-2377 or visit our website http://www.agriculture.gov.sk.ca/.
by Nadia Mori
Regional Forage Specialist
September 3, 2013 11:39
Can you identify this plant? Do horses eat it?
Plant sample cut in hayfield
Plant samples in garden, yard and hayfield
Photo credit: HorseOwnerToday.com
September 14, 2012 12:19
Chelsey Carruthers, M.Sc., AAg
Regional Livestock Specialist, Saskatchewan Ministry of Agriculture
Every fall with the first frost looming, livestock producers worry about nitrate in their forages. What is nitrate, where does it come from and what can you do about it?
What is nitrate?
During normal growth, plant roots take up nitrogen from the soil in the form of nitrate and the plant converts it to protein. When plant growth is stopped by an event such as hail, frost, drought or chemical damage, this normal process is affected and nitrate accumulates in the plant.
When ruminant animals eat plants containing nitrate, their rumen microbes convert it to nitrite, which is much more toxic. At low levels, nitrite is handled by the rumen microbes and used for protein production. However, at high levels, the microbes can’t keep up. Nitrite is absorbed into the blood stream where it can cause problems by decreasing the oxygen carrying capacity of the blood. Animals can die due to lack of oxygen. Symptoms of nitrate poisoning include trouble breathing, weakness, diarrhea, muscle tremors and death. At lower levels, nitrate poisoning can cause decreased productivity and abortions.
How can you tell?
Nitrate accumulates in the stems and leaves of plants following periods of stress. However, not all plants are equally affected. Nitrate tends to accumulate in annual forages, such as those used for swath grazing and green feed, and some weeds, and is usually higher in immature plants. Legumes such as alfalfa rarely accumulate high levels of nitrate. Crops that have been fertilized with nitrogen will be at higher risk of nitrate accumulation.
After a stress that kills the plant, such as a hard frost, the crop should be harvested as soon as possible. The plants will not recover, and cannot clear the nitrates. Because the plant roots will continue to absorb nitrate from the soil for a few days following plant death, the nitrate level in the plant will continue to rise during this period.
If the stress to the plant has been mild enough for the plant to recover and continue to grow, harvest should be delayed about ten days. This will give the plant a chance to use up the stored nitrate and convert it to protein.
If you suspect your harvested forage is high in nitrate, a feed test can be done to determine the nitrate level. This will give you an idea of what you are dealing with, and what you can do about it.
What can be done?
Not all frozen forages will be high in nitrate. Testing is the only method for determining the nitrate level and developing a plan to deal with high nitrate feed. Most of the time, the risk to livestock can be decreased by diluting high nitrate feed with low nitrate feed. Water can also be high in nitrate, and should be tested as well. A combination of feed and water both high in nitrate can be a more serious problem. Livestock should be maintained in good body condition, and provided with a diet well balanced in energy, protein, vitamins and minerals. Livestock should also be introduced to higher nitrate feeds very slowly, and monitored carefully.
Understanding the process of nitrate accumulation, the risk factors, and the importance of feed testing can help you to plan ahead and deal with high nitrate feeds to protect the health and productivity of your livestock.
For more information on this or other topics please call me at (306) 946-3237, the Agriculture Knowledge Centre at 1-866-457-2377 or visit our website: http://www.agriculture.gov.sk.ca/
July 23, 2012 17:51
BY MICHEL TREMBLAY, PAG.
PROVINCIAL SPECIALIST, FORAGE CROPS
The 2012 growing season has been characterized by significant rainfall across the agricultural zone of Saskatchewan, following a dry, warm winter. In Saskatchewan, spring precipitation is the largest single determinant of yield of cool season forage species. With favorable soil moisture present in nearly all areas of the province, a good forage crop should be expected. Some producers have noticed that their alfalfa fields are not yielding, considering the soil moisture present. The following factors may be contributing to decreased alfalfa vigor and yield.
The alfalfa weevil (Hypera postica) is a pest of alfalfa crops, and is increasing in occurrence in Saskatchewan. Alfalfa weevils have been observed predominately in the southeastern and east-central parts of the province in alfalfa hay and seed fields. Adult weevils are approximately 5 mm in length, brown in colour, with a darker brown stripe from the head running down the back. The alfalfa weevil is a snout beetle, with a pronounced hook shaped proboscis at its anterior end. The larvae, when newly hatched, are yellowish green. At maturity, larvae are approximately 8 mm in length, and have a black head and a white stripe down the centre of its back. Adult weevils overwinter under plant debris and soil in and around alfalfa fields. Weevils emerge in spring and begin feeding on alfalfa leaves, creating round holes in the leaves. Females, when ready to lay eggs, chew a hole in the stem of the alfalfa plant and deposit from one to 40 eggs per stem. The bright yellow eggs can be seen with the naked eye if the stem is cut open. Eggs hatch one to two weeks after being laid, and the emerging larvae initially feed within the stem before moving to the developing buds, then newest leaves.
Alfalfa weevil larvae leaf damage.
Source: Saskatchewan Agriculture
Damage begins as pinholes and progresses to extensive feeding damage to leaf surfaces between veins, resulting in a ragged, skeletonised leaf. Heavily infested fields may not have flowers present, as the larvae will remove developing inflorescences. Often the first sign of weevil damage is the discoloration of the crop as the larvae feed. Evident from the field edge, the crop will develop a whitish sheen, or frosted appearance, due to foliar damage.
Alfalfa weevil larvae.
Source: Saskatchewan Agriculture
Larvae feeding occurs predominantly early in the season, in mid-June to mid-July. Mature larvae move down to the base of the plant or onto the soil and spin a lace-like cocoon. The adults emerge from the cocoon in one to two weeks. The larvae represent the most destructive stage of the alfalfa weevil life cycle, and most weevil damage occurs on the first cut. Usually a single generation of the weevil occurs per season in northern climates.
The most cost effective control can be cultural. Cutting when the potential for significant weevil damage becomes apparent will stop yield losses. If the infestation is severe and early cutting is not feasible, alfalfa weevils can be controlled by using insecticides as per economic thresholds indicated below.
Economic thresholds for alfalfa weevil pesticide application
Foliage: 35-50 per cent of foliage tips show feeding damage.
Larvae: 20-30 3rd/4th instar larvae per 90o sweep of insect sweep net.
30 cm crop height and one larva per stem.
40 cm crop height and two larvae per stem.
Three larvae per stem requires immediate action regardless of height of crop.
Two or more active larvae per crown (four to eight larvae per sq. ft) on regrowth after the first cut.
April 23, 2012 12:25
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March 23, 2012 10:35
Nadia Mori, MSc, PAg, Regional Forage Specialist
Watrous Regional Services Office
Saskatchewan Ministry of Agriculture
Managing pastures for maximum productivity sounds easy in theory but once weather fluctuations, insect or wildlife damage, and other unforeseen circumstances enter the equation, pasture management quickly turns into a complex balancing act. Grazing management mistakes are bound to happen when dealing with the complexity of a pasture ecosystem. Learning from these mistakes is a good preparation for future unforeseen circumstances and better risk management in your grazing system.
1. Looking only to the past to determine stocking rates.
Using the same stocking rates year after year often results in pasture degradation. What may have worked in the past may not be appropriate in the present. Most grazing animals have increased in frame size, thereby increasing forage demand for a single animal. Each year will also present a different moisture situation and therefore different amounts of available forage. Properly balancing your forage supply and animal demand based on weather patterns and herd requirements is recommended.
2. Thinking that more animals grazed means higher profits.
As stocking rates go above what a pasture can carry sustainably, animal performance and animal health will start to decline. As forage supply becomes inadequate, animals are also more likely to graze harmful and toxic plants. In addition to compromised animal performance, the grazing pressure on your desirable forage plants can lead to reduced pasture health. Long periods of rest may be necessary to restore pasture productivity. Reduced pasture productivity can be costly if additional feed needs to be purchased to meet animal nutritional requirements. All these factors reduce your profit.
3. Thinking that leaving forage behind is a waste of feed.
Drought is always a matter of when, not if it occurs in Saskatchewan. Keeping stocking rates conservative is the best drought insurance policy. Well rested, vigorous forage plants with a well developed root system will stand a much better chance of survival than an overgrazed, stressed plant with a compromised root system. Forage not used in above-average rainfall years can provide carry-over feed for periods of moisture shortfalls. Left-over forage material also turns into litter which helps protect the soil surface from soil erosion and keeps soils cooler and moister during the heat of the summer.
4. Following the same pasture rotation year after year.
Grazing during rapid spring growth can be stressful to forage plants. Using the same pasture for spring turnout or during rapid spring growth, is taxing on forage plants. Desired plants are often selectively and repeatedly grazed during this rapid growth stage, which may give weedy or undesirable plants an opportunity to take over. Deferring grazing during critical plant growth periods, using pastures at different seasons of the year, and rotating through pastures in different sequences from year to year will help in maintaining good pasture health.
For more information, please contact:
Watrous Regional Services Office (306-946-3220);
Agriculture Knowledge Centre (1-866-457-2377); or
Visit our website at www.agriculture.gov.sk.ca.
September 1, 2011 17:51
Charlotte Ward, MSc, PAg – Regional Forage Specialist - Yorkton
The typical production schedule for a perennial forage crop usually consists of 3 to 5 years of high yield (honeymoon period) followed by a rapid decline in productivity. Once this 3 to 5 year honeymoon period is over, factors such as declining soil fertility and decreasing plant numbers typically result in lower production. Another key factor that will affect long-term stand productivity is timing and frequency of harvest – whether or not producers take a 2nd cut of hay or grazing and the timing of that harvest.
Proper management of these stands from now until freeze up can help to mitigate the natural decline in productivity.
How can soil fertility affect stand productivity and why should be thinking about it this fall?
As we harvest perennial forages and remove the plant material from the field, we are also removing a tremendous amount of nutrients from the soil as well. High yielding forages will remove more nutrients than low yielding forages, which will in turn likely remove more nutrients than if the stand were grazed. Over time we need to replenish these nutrients. Manure, commercial fertilizer and even feeding livestock on the field can all be used as tools to import nutrients.
If alfalfa makes up 50% or more of the production in the stand and was properly inoculated at seeding, nitrogen is generally not a concern in the forage stand as the alfalfa will fix all the nitrogen that the stand needs. Phosphorus, potassium and sulphur are the three nutrients that we tend to focus more on in stands that contain a significant portion of legumes as legumes are high users of these nutrients. Phosphorus and potassium are of particular importance as they contribute to root and nodule health and the over-wintering capability of the plants. Both of these nutrients can be fall applied as they are relatively immobile in the soil and they will not leach or volatilize to the atmosphere like nitrogen will. Fall application of these nutrients can also help to decrease the work-load next spring. The most cost-effective way to know where your stand is at in terms of soil fertility is to do a fall soil test.
How does the timing of harvest and frequency of harvest affect forage yield?
Improper cutting of alfalfa stands can lead to winter kill. Understanding alfalfa physiology can help to avoid this problem. In the plant, energy is produced in the leaves through the process of photosynthesis and is used to fuel plant growth. As the plant produces excess energy, it is stored in various plant parts such as the roots and crown. The stored energy is used for regrowth following cutting, plant maintenance over winter and growth during early spring.
When an alfalfa plant is cut, few leaves remain and the plant may draw on stored energy reserves for regrowth. Generally the plant will need 6 weeks to replace leaves and replenish stored reserves to pre-cutting levels. Thus there is a 6-week critical period after cutting that the plant needs to ensure that it has good energy reserves going into winter. This is of particular importance to producers looking to take a second harvest off their fields, either through mechanical harvest or grazing livestock.
Plants harvested after August 15th may not obtain six weeks of good weather of replenish reserves before a hard frost and can go into winter with low energy levels. Plants with low energy levels are more susceptible to winter kill. If it is necessary to take a second harvest, producers should wait until after a killing frost as the plants will shut down and will not try to mobilize energy reserves.
Fall harvests should be approached with caution as harvesting plants after August 15th reduces the stubble height of the field which is important for trapping snow and spring moisture next year. Standing alfalfa will not only trap snow this winter, but will also cover the soil next spring and summer to minimize moisture lost through evaporation.
What can producers do this fall to optimize forage yield next year?
· Avoid cutting between August 15th and the first killing frost
· Ensure there is adequate soil fertility, including phosphorus and potassium which is particularly important for root health and development as well as nodule health
· Manage stubble for maximum snow cover
January 26, 2011 16:25
Hay is hard to find in some areas. Because of a scarcity of hay in many regions, can you just skip feeding hay this winter and make up the deficit by doubling your horse’s grain ration? The answer is an emphatic NO.
Consider availability, cost, and practicality when choosing ways to provide adequate fiber.
Hay, or some other source of fiber, is absolutely necessary to the health and function of the horse’s digestive tract. Overconsumption of grain is characteristically followed by colic, gastric ulcers, or laminitis, so this is not an option to consider. Aim for an average of 1.5% of the horse’s weigh in hay or equivalent forage each day (approximately 15 pounds of hay for a 1000-pound horse, or 7 kg for a 450-kg horse), adjusting up or down depending on the horse’s age, use, and metabolism.
Why is fiber so important in the equine diet?
Consumption of grass, hay, and other forage fulfills both physical and psychological needs. Horses have a strong desire to chew, and also to have the full-gut feeling that comes from eating a lot of fiber. Deprived of adequate forage, horses tend to chew on trees, fences, stalls, and anything else that is available. A steady supply of forage helps to maintain the optimum types and numbers of microorganisms in the hindgut. These bacteria and other organisms transform fiber into energy the horse can use for growth or performance. The proper balance of beneficial bacteria prevents an overgrowth of harmful organisms that may upset digestion. As well as aiding the passage of food through the digestive tract, adequate fiber provides bulk and weight in the intestines. This helps to keep them from twisting and looping around each other, possibly leading to tissue damage and colic.
Is there a particular need for forage during cold weather?
A near-constant supply of forage is an important factor in keeping horses warm in the winter. The vast fermentation vat of the horse’s hindgut steadily produces heat that can’t be supplied by an all-grain diet.
My local hay dealer doesn’t have hay for sale this year. Should I buy hay from outside my region?
Obviously, not all hay is the same, but with some precautions, you should be able to use hay that is shipped in from other regions. Things to look for include:
• Blister beetles. Alfalfa hay may contain these small insects that are highly toxic to horses. Signs of ingestion may include colic, depression, loss of appetite, and straining to urinate.
• Unfamiliar weeds or plants. Hoary alyssum, a pasture weed, has been found in alfalfa hay baled in Michigan. Horses consuming the plant showed diarrhea, swollen legs, fever, and signs of laminitis.
• Selenium levels. The amount of selenium in hay is influenced by the level of the mineral in the soil where the hay was grown. Horses need a certain amount of selenium, but high levels are toxic. Hay from some western states may have this problem. Signs of selenium toxicity include laminitis and a loss of mane and tail hair.
• Vitamin content. Levels of vitamin A and E drop slowly as hay ages. Hay baled last year, or even very early in the current year, may not contain enough vitamin E to keep horses in good health through the winter; signs of deficiency include muscle weakness, tremors, and weight loss. Vitamin E level depends less on the hay’s place of origin than on how long it has been in storage.
• Quality. Ask hay brokers for a nutrient analysis before making a purchase, and examine the hay before accepting delivery. Good hay will smell fresh and clean without a moldy odor. Check the center of a few bales; hay that appears dry and yellow on the outside of the bales may still be green and fresh inside.
I still don’t have enough fresh hay to supply my horse all winter. What can I do?
If at all possible, some hay should continue to be fed. Owners can use alternative fiber sources to round out the diet if the amount of traditional hay must be reduced. Ideas for stretching your hay supply include:
• Feeding chopped hay, available at some feed stores in 50-pound (23-kg) bags. Palatability is an asset; expense and storage may be problems.
• Adding some hay cubes to the horse’s diet, soaking the cubes if necessary before feeding. Alfalfa, timothy, and mixed cubes may be available, and in some parts of the country a hay cube fortified with vitamins and minerals is available. Many horses can get along well on mixed cubes, and selection should match the horse’s needs. Because there is less waste with cubes than with loose hay, you often do not need to feed an equivalent weight. Don’t put all the cubes out at one feeding, as the horse will probably gobble them up quickly and then have nothing to eat for hours.
• Adding beet pulp to the ration. This “super-fiber” can make up a maximum of 20% to 30% of the diet, is easily digested, and can be bought in bulk at feed stores. Many people advocate soaking beet pulp before feeding, so use of this fiber takes a little more time and management than some other choices. Beet pulp is low in phosphorus and some other minerals and vitamins.
• Feeding a “complete” or “fiber-included” feed that incorporates both the forage and grain portions of the diet. Be sure that the feed actually includes forage; some companies use the “complete” designation to indicate a fortified grain mix, not a product that offers forage. This type of feed should be offered in several small feedings throughout the day rather than as one large meal.
• Using clean older hay. Even if last year’s hay doesn’t have optimum levels of some vitamins, it gives the horse something to chew on. Older hay that is clean but very dry can be moistened before feeding to make it more palatable, and the nutritional shortfall can be made up by adding a vitamin-mineral supplement.
• Feeding straw, either baled or chopped. Clean, non-moldy straw is palatable to many horses and contains nearly as many calories as some grass hays, although it is lower in protein and phosphorus.
• Allowing horses more access to pasture. If non-grazed fields are available, horses will continue to eat grass all winter even though it is not actively growing. In fields that have been grazed all summer and fall, horses may be forced to eat brushy or toxic plants as the only choice. Before counting on this source of forage, owners should walk the fields to make sure there is something to eat.
To view the complete article go to: http://www.equinews.com/article/forage-alternatives