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
July 27, 2012 15:14
BY MURRAY FEIST, RUMINANT NUTRITION SPECIALIST
Weather conditions this summer have been conducive to the formation of blue-green algae blooms on dugouts and ponds. Nutrient rich runoff flowing into a body of fresh water combined with warm daytime temperatures in the summer accelerates algal growth, including that of blue-green algae.
Blue - green algae is not an algae, but a bacteria called "cyanobacteria." This bacteria produces toxins that can cause skin and eye irritations, gastroenteritis, liver and nervous system damage, sickness and, at times, death.
A surface bloom of blue-green algae may look quite differently depending on which species is dominant. Some will have a shimmering blue-green colour. The bloom may also have a foamy sheen-like appearance that looks like spilled paint floating on top of the water. Heavy blooms may appear like a solid shimmering blue-green sheen across the water’s surface, may have an appearance and consistency similar to pea soup, or may have a mixture of the colors tan, purple, grey, green or blue-green.
If blue-green algae is identified in a water source, all livestock, pets, and human contact should be prevented. The water will require treatment.
The most common treatment of blue-green algae in an open dugout or pond is with a registered product containing copper sulphate. A treatment rate of one pound (0.45 kilogram) of copper sulphate (by weight) will treat 100,000 gallons (1 kg/1,000,000 litres). There are two common application methods: the copper sulphate can be dissolved in warm water, which is then sprayed over the water’s surface; or, the copper sulphate can be weighted into a cloth bag with a rope spread from side to side, and with the assistance of another individual, the bag can then be dragged back and forth across the water’s surface. When treating dugouts, the objective of the treatment is to target the top meter (1.0 m) to kill the algae.
Copper sulphate works by killing the blue-green algae. Doing so releases the blue-green algae toxins into the water. Therefore, it is recommended that 12 to 14 days should pass prior to any livestock, pet and/or human contact with the contaminated water. If treating a dugout containing fish, it is recommended that only one-third of the dugout should be treated, using one-third of the recommended copper sulphate weight applied in treatments over a three day period.
The treatment process described above applies to non-draining waterbodies, such as dugouts, which are wholly contained on private land. In the case of waterbodies that drain to adjacent properties or waterways, a permit for the chemical control of aquatic nuisances is required from Saskatchewan Environment.
For more information, call the Agriculture Knowledge Centre at 1-866-457-2377.
May 25, 2012 12:58
Nadia Mori, MSc, PAg, Regional Forage Specialist
Watrous Regional Services Office
Saskatchewan Ministry of Agriculture
Integrated pest management (IPM) is a well established practice in crop protection and can be a valuable approach in forage stand management. IPM means to have a well rounded weed and pest control plan which considers at all options from prevention to control methods available. The following components should be part of an IPM approach:
1. Monitor Weeds
Monitoring is the process of regularly inspecting pastures to determine if any undesirable plants are present. Scouting also identifies conditions which could favour the development of a weed infestation. For example a recently flooded area on a slightly saline soil may start to convert to foxtail barley.
2. Pest Identification and Biology
Correct pest identification is necessary in order to select appropriate and effective control measures. Consult with an agrologist or biologist if you are unsure about the identification of a weed or insect found in your pasture. Some basic understanding of the biology of the pest is also critical to effective control and prevention. For example, since annual weeds reproduce by seeds, control measures will be more effective if done before seeds are produced.
3. Weed Control
Weed control measures must be evaluated in order to select the most appropriate control measures and combine control methods effectively. Herbicide application is one form of control but other alternatives like providing rest during the growing season, mowing, targeted grazing, burning, biological controls and even hand rouging should all be considered. Each control method will have associated costs and make some solutions more economical. For example, cost of weed control procedure, cost of lost production, and cost of damage to non-target plants are some costs to be considered.
4. Evaluate Weed Control
Control measures must be evaluated to verify the degree of effectiveness. If adequate control has not been achieved, the reasons for the lack of effectiveness should be identified and corrected. Effects on non-target plants and impacts away from the target area must also be identified.
5. Recordkeeping and Program Management
A complete and accurate set of records is basic to any pest control program. Records will assist in identifying key information such as: which pests have been a problem; where the infestations occurred; how successful different control options proofed to be; what the actual cost of the chosen control option was; during which conditions control options worked or not; which conditions allow certain pests to become a problem (for example, site disturbance, drought conditions, or overgrazing).
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.