Federated Co-operatives Limited GRAZING WHOLE CORN WINTER COW NUTRITION Sharon Klinger Ruminant Nutritionist
Corn and Cow Nutrition
Water Energy Protein Minerals Vitamins Basic Animal Nutrition The cow is a machine: Water, energy, & protein are the fuel Minerals & vitamins are the oil
Minerals and Vitamins A year-round requirement as vitamins and minerals are required for: Maintenance Growth Reproduction Gestation Lactation Deficiencies take time to be fixed
Most important nutrient Snow? Extra energy required Make sure adequate Quality Water Prairie water typically high in salts & sulfur
Energy Grains and Forages Measure T.D.N. Total Digestible Nutritients» NEg, NEm, NEl
Protein Feed protein sources true protein vs. non-protein nitrogen (NPN) degradable vs. undegradeable (by-pass) Microbial protein synthesized by rumen microbes from NPN Feed the rumen
Minerals Involved in all aspects of metabolism Macro vs. Micro refers to the relative amounts required macro (%): Ca, P, Mg, K, Na, Cl micro (mg/kg or ppm): Se, Co, Cu, Mn, Mo, I, Fe
Calcium and Phosphorus Rule of Thumb Ca:P ratio should be no less than 1:1 and no greater than 7:1 Legume forages: Hi Ca, moderate P Grass forages: low Ca, moderate P Cereal grains: low Ca, high P - Corn
Vitamins Required for various body functions enzyme precursors Antioxidants ADE
Feed Intake The most important variable of nutrition key determinant of performance Cattle eat to meet their energy needs
Factors Affecting Energy Req & Intake Cold stress may increase intake by 10-30% Condition & hair coat under conditioned cow will eat more wet coat is poor insulation Physiological state reduced intake before calving followed by rapidly increased intake during lactation Forage quality lower quality reduces intake
Effect of Forage Quality on Intake Forage Quality Intake (% BW) Dry matter intake of 1200 lb beef cow High 1.75 2.5% 21 27 lbs Medium 1.50-1.75% 18 21 lbs Poor 1.00 1.25% 12 15 lbs
Corn
Corn Heat Units
Corn Heat Units AVERAGE ACCUMULATED CHU FOR SILAGE PRODUCTION (Half the years you will get more CHU, half the years you will get less CHU) *Adapted from Saskatchewan Ministry of Agriculture
Corn Heat Units different areas Alberta: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/sag6 442/$FILE/onl_s_9_twp_annual_normals_19712000.gif Saskatchewan: http://www.agriculture.gov.sk.ca/default.aspx?dn=0abdf069-53e8-4d81-9f99-17b14d8866b7 Manitoba: http://www.gov.mb.ca/agriculture/weather/images/figure20.gif http://www.gov.mb.ca/agriculture/weather/images/figure22.gif www.farmzone.com can also give an estimate
Grazing Corn Maturity
Why Graze Corn? Nutritional value of whole plant corn can meet or exceed a beef cow s requirements Nutrient Requirements for Beef Cattle 1400 lb (635 kg ) (BCS 3.0) CP (%) TDN (%) NEm (Mcal/d) 1st trimester 7 49 10.7 2nd trimester 8 51 12.5 3rd trimester 9 54 15.2 (adapted from NRC 2000) When corn reaches maturity, it loses feed value as forage, (leaves/stalks) but compensates in grain/cobs Average C.P. 7-8% Average TDN 61-66%
Grazing Corn Reduce winter feed costs Usually nutritionally will match mid to late pregnancy nutrition of a cow (may need protein supplementation) Low management (after adaptation)
Grazing Corn - Adaptation Important to adapt cows to minimize grain overload Utilize a small grazing area, or limit grazing time Feed grain for at least a week prior to going out on corn Have extra roughage available Don t turn out hungry cows
Grazing Corn How many acres do I need? 200 cows for 30 days 30 x 200 = 6000 cow grazing days Based on 250 cow days per acre 6000/250 = 24 acres
Grazing Corn Management Move cows every 3-5 days to have low residue left behind Manage and Monitor Provide shelter
Test It Grazing Corn Know what you are working with Wet Chemistry approx $45 per test Results in 2 weeks time
Grazing Corn How do you sample it? Cut a minimum of 3 whole corn stalks (including the cobs) average stalks -not the best, not the worst We take care of the preparation
Grazing Corn Mineral Strategy Corn is low in calcium Supplement at least a 2:1 mineral, or a 3:1 mineral is ideal Cows will consume higher amounts of mineral and salt
Grazing corn Protein Supp Yearlings/Growing cattle/late gestation Supplement protein through forage, tubs, blocks
Grazing Corn - Tips Use electric fence. Make sure ground is frozen and dry Force cows to clean up Have a backup plan
Grazing Corn Benefits Extends the grazing season Reduces feed costs Cow spreads the manure herself Reduces labour and machinery costs Reduces reliance on stored feeds Corn is a good choice for winter grazing as it stands up well in the snow
Questions?