Balancing on the Slippery Slope of Grazing to Perfection continued from page three
PH Power No one really knows what the p stands for (power or potential, probably) but the H stands for Hydrogen. The scale runs from 0 on the acidic side to 14 at the alkaline end. A healthy cow should produce urine with a pH of 7. If she has been eating too much protein, her dung will be toward liquid and her pH high. In this condition she is unable to absorb and utilize the minerals she takes in, which can create a mineral deficiency that supplements do not address because she is not absorbing them. If the cow’s urine pH is right, minerals offered cafeteria style are taken up in the right amount to be healthy, the immune system works, parasites are shed, growth and conception is maximized.
Diet Selection Selection is the key to hydrogen-protein balance. The cow instinctively chooses the right thing to eat—if it is available. The energy in a plant consists of carbon, hydrogen and oxygen. Energy is released when carbohydrates burn (metabolize). Hydrogen or energy is strongest in the tips of the leaves, with protein being closer to the roots. Oxygen is the controlling factor in how well the energy burns. Ketosis is trying to burn hydrogen in the absence of oxygen. Protein is not a good source of energy because the ammonia gas gets trapped in the rumen and can cause bloat. If the urine pH is above 7, you have evidence of protein being used as an energy source. Cafeteria-style minerals allow each individual animal to supplement its diet by taking in the right amount of each mineral without having to take in too much of another as they might do in a prepared mix. They will seek what they are missing from the soil/plant offerings and return some to the soil to gradually improve the mineral balance there. When in animal performance mode—two months before calving to the end of breeding— maximum selection is key to getting animals fat and healthy. Stocking rate determines the amount of selection. Either give the animals more space in which to choose their diet, or move the herd through the paddocks faster. For calving, select a large area with plenty of selection for your 45 days of calving, then move the mamas in a manner that allows them to come back for their calves and allows calves to go under the single-wire electric fence. Ian calves mid-summer and weans his calves at 10 months, then moves them through the 16
IN PRACTICE
paddocks about 20 days or so after the mothers, who are moving fast in animal performance mode. This gives the calves a diet of re-growth leaves with maximum energy and protein, with less fiber. Although it is intentionally overgrazing plants (re-biting before complete recovery), it is acceptable if total recovery occurs after the calves have moved through. Full recovery for grazed grasses yields: relaxed grasses that don’t feel stressed enough to send up a seed stalk; lots of broad-leaved, dark green vegetation; longer periods in the vegetative state; longer, deeper roots; and more bulk.
Animal Performance or Landscape? Controlling trample to graze ratios can build soil and soil fertility to support increased biomass. Animal performance mode allows a cow to selectively eat what she wants, so is high on the graze end of this teeter-totter. Wide paddocks allow cattle to spread out a bit for more graze than trample and greater selection for the animals. When not in animal performance mode, you can put your animals into landscape mode. Here, they trample more than they eat—up to 90% trample—in order to put any remaining standing grasses in contact with the soil, banking all that carbon for next season’s forage. Think energy in = energy out plus at least 10% “interest.” To get the highest trample ratio, use long, thin paddocks with the cattle moving through 4 or 5 abreast. Send them up one lane and back the next. Make an enclosure to pen a dense herd for an hour or two, then watch that spot after recovery to get an idea what high stock density can do in that location.
Bacteria to Fungi The bacteria:fungi ratio can be manipulated by the amount of green grass trampled versus brown. The green grass litter tends to favor bacteria where as the brown will favor Fungi. Monoculture grassland tends to be bacteria dominated. To move this to incorporate legumes it needs to have some Fungi in it. For native grass species in America to establish they need more Fungi than for legumes. Bacteria sequester nitrogen, make the mucous necessary to glue soil particles together, and are the base of the soil food web’s food chain. A teaspoon of productive soil generally contains between 100 million and 1 billion bacteria. That is as much mass as two cows per acre. Fungi provide water, nutrients and minerals to their host plant, have the enzymes necessary to digest woody fibers, and make glomalin, another soil particle glue so useful in retaining carbon it may be one of the measurements used in carbon
March / April 2011
Ian Mitchell-Innes trading (google “glomalin” for a fascinating education in soil carbon). Both bacteria and fungi are necessary and desirable for healthy soils, and altering the balance between the two can favor some plant communities over others. For more information you can read Elaine Ingham’s Soil Biology Primer at the NRCS website http://soils.usda.gov/sqi/ concepts/soil_biology/soil_food_web.html
Monitoring—The Daily Habit Monitoring is an important part of grazing to perfection. Monitoring animal performance is pretty much a daily habit. What would be your first indication that the animals are becoming stressed? Dipping litmus paper into a puddle of a cow’s urine monitors the urine pH. Pink eye and other ailments can be a sign the pH has been incorrect for a while. If the cattle want to move before normal, they are not getting optimum nutrition. Check the rumen fill on the left side just in front of the hip bone—it should be full. Check the coat—it should be shiny and lying flat. If the hairs are dull, rough and/or standing up, the animal has been stressed in some way for three months or so. Excessive flies are a sign of a less than ideal condition. The dung should be neither too firm nor really runny. Failure to conceive tells you to look hard at management practices. You should also monitor the land for full recovery of plants before re-grazing. Spacing between plants should be getting smaller, grasses should be broad-leafed and dark green, and litter should be covering the space between plants. Ian emphasizes that form follows function. The function of an animal is to perform in the environment into which it is born. The size of a cow needs to be determined by the amount of energy capture in the forage. To learn more about HMI’s 2011 Ian Mitchell-Innes Course Series, read the ad on page 22 or call HMI at 505/842-5252.