Beef Cow Nutrition in Animals - Study Guide Exam 2 | ANSI 3653, Study notes of Zoology

Download Beef Cow Nutrition in Animals - Study Guide Exam 2 | ANSI 3653 and more Study notes Zoology in PDF only on Docsity! Animal Nutrition Exam 2 Beef Cow Nutrition:  Forage Quality: CP% CF% % BW Excellent >13 20-29 2.5 Medium 7-12 30-39 2.0 Poor <6 >40 1.5  Forages become less digestible as they grow. The more developed the plant, the lower the digestibility.  Crude fiber and crude protein content; the higher the CF the lower the digestibility. Immature plants have less developed cell walls.  Nutrient intake can be estimated by lab testing forages or by book values Forage intake is estimated by the maturity and nutrient content and by the forage guideline table.  Optimum body condition is 6  At body condition 3 a cow will not cycle  A cow must gain/loose 100 lbs to change one body score  Post partum interval- Days from calving to first observed estrus BCS 6: 30-45 days BCS 4: 60-120 days  Production Periods: 1) Late Gestation 2) Early Lactation 3) Breeding-Weaning 4) Mid-Gestation  Late gestation and early lactation are critical production periods because there is poor forage and a high nutrient requirement.  High plant protein feeds: 30-40% CP, Composed of primarily soybean meal, cottonseed meal, sunflower meal. The nitrogen requirement of ruminal MCOs is satisfied so MCO numbers increase so digestibility increases and intake increases (positive associative effect)  High energy: Low protein feeds: 20% CP, Composed primarily of cereal grains (corn, milo, wheat). Introduction of significant starch into the rumen decreases ruminal pH thus decreasing MCOs. Negative associative effect.  High energy: Low protein feeds: 20% CP, Composed primarily of by-product feeds (wheat midds, soy hulls, etc). Since by-product feeds are digestible fiber, feeding this supplement will increase energy intake without introduction of significant quantities of starch. Digestibility and intake are not affected.  Non-Protein nitrogen feed: 20-30% CP, Composed primarily of molasses and NPN (urea). NPN is rapidly hydrolyzed in the rumen. Available carbon chains are limited due to poor digestibility of weathered mature forage. Poor utilization of fed nitrogen.  To determine if there is an Energy or Protein is a concern, forage availability and body condition must be assessed.  If forage is adequate and the cows are thin then ENERGY must be supplemented with high energy low protein forage. The supplement selection should be based on cost of TDN.  If forage availability is limited then ENERGY must be substituted with harvested forages.  PROTEIN is the primary concern if there is adequate forage and the cows are in acceptable condition. 30-40% CP supplements lead to a positive associative effect. Supplement selection should be based on price per lb of CP.  NPN supplements for cows on weathered mature grass are well utilized because the ruminal MCOs have a ready source of CHOs.  Measuring % of usable NPN and CP: CP – NPN = CP from natural sources NPN x 50% utilization = % CP from NPN Natural CP + CP from NPN = Total CP value  Mineral Supplements- %Ca: %Phos: %Salt Wheat- 8:4:25 Native grass- 16:8:30 Bermuda grass- 12:12:12  Copper Sulfate (Inorganic)- 70% absorption Copper Oxide (Inorganic)- 20% absorption Copper Lysine Complex- 100% absorption  Organic trace mineral deficiency: -Depigmentation of hair -Limited estrus activity -Recurrence of estrus 35-55 days after apparent conception -Calf deaths at 7-10 days old with no reason  Trace mineral deficiency can be tested by a liver biopsy  Low liver copper levels: -Mature cow’s normal level is >40-60 ppm -Young calf’s normal level is > 300 ppm  Vitamin A deficiency is a problem with fall calves and first calving females grazing on dormant forages. Calves may have watery eyes that can become blindness, cows have no symptoms. Supplements and shots may be used. Immature and mature forages still have their vit A.  Critical Body Temperature is 30° with dry coat and 50° if coat is wet. Find the temperature change from critical temp to wind chill temp. 1% TDN is added for a dry coat and 2% for a wet coat. Calf Nutrition:  Critical colostrum is the most important requirement of a newborn calf.  Insufficient energy and protein consumption by late gestating females result in low colostrum levels which can lead to calf scours and death.