Forage Quality and Livestock Nutrition on Pasture Patrick Davis, Ph. D. Johnson County MU Extension Livestock Specialist
Topics Ruminant Nutrition Factors Effecting Forage Quality Nutrient requirements Feeding Strategies Fescue Toxicity
Ruminant Nutrition Ruminant physiology 4 Stomachs Energy and protein metabolism
Ruminant Nutrition Ruminant Fore stomach fermentative digestion microbes produce energy and protein Reticulum - rumination Rumen - fermentation Omasum - Feed particle size reduction Abomasum (true stomach) Gastric stomach enzymatic digestion
Ruminant Nutrition Features of the Rumen Gas pocket Fiber mat Fluid fraction Resident microbial population Bacteria Protozoa Fungus Viruses
Ruminant Nutrition Protein RDP RUP Microbial Cell Peptides Carbohydrates Cellulose and Starch AA Microbial Enzymes Sugars NH 3 + Carbons Skeleton VFA Urea Via Urea Cycle AA Synthesis Microbial protein for use by animal to meet its needs For animal Growth Reproduction Lactation For Microbes Cell growth Cell division
Ruminant Nutrition Energy Intake 100% Fecal Energy 30% Digestible Energy Metabolizable Energy Urinary Energy 5% Gaseous Energy (CH 4 ) 5% Heat Increment 20 % Net or Retained Energy (NE or RE) Production 20% Maintenance 20%
Factor that influence forage Quality Maturity
Factor that influence forage Quality Species
Factor that influence forage Quality Plant Parts 1 st bite: leaves with low fiber 2 nd bite 3rd bite: stems with high fiber
Nutrient Requirements Nutrient Classes Water Energy Protein Vitamins Minerals All are required
Nutrient Requirements Maintenance Nutrients required to stay alive No productive functions Growth Lactation Pregnancy NEm = 0.077 Mcal * (EBW kg) 0.75
Nutrient Requirements Type / Breed Genetic role in maintenance Maintenance Multiplier English / Angus, Hereford 1 Dairy / Holstein, Jersey 1.2 Continental Limousin, Charolais, Chianina Gelbvieh Simmental, Braunvieh 1.0 1.1 1.2 Bos indicus Brangus Brahman 0.95 0.90 NRC, 2000
Nutrient Requirements Cattle efficiency status Residual feed intake (RFI) Actual intake Predicted intake = RFI The most efficient calves consumed 4% less feed than medium cattle 15% less feed than high cattle Group DMI FCR RFI Low 21.10 7.02-0.95 Medium 22.02 7.72-0.14 High 24.31 8.48 +0.91 Nkrumah et al., 2004
Nutrient Requirements 20 1300 pound cow energy requirements Mcal NEm / day 15 10 5 Pregnancy Lactation Maintenance 0 1 2 3 4 5 6 7 8 9 10 11 12 Months since calving
Nutrient requirements Metabolizable Energy, Mcal/d 20 15 10 5 0 Effect of replacement heifer body size 1400 lb Mature Weight 1200 lb Mature Weight 1000 lb Mature Weight 1 2 3 4 5 6 7 8 9 Months from Conception
Nutrient Requirements 1 st calf heifer Energy requirements 20 Mcal NEm / day 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 Months since calving Growth Pregnancy Lactation Maint
Nutrient requirements Metabolizable Energy, Mcal/d 35 30 25 20 15 10 5 0 Effect of milk production level and pregnancy 1 2 3 4 5 6 7 8 9 10 11 12 Months Since Calving 1200 lb Cow - 30 lb Milk/d 1200 lb Cow - 20 lb Milk/d 1200 lb Cow - 10 lb Milk/d
Nutrient Requirements 10 Energy Required for a 650 lb calf Mcal / day 8 6 4 2 NEg NEm 0 0 0.5 1 1.5 2 2.5 ADG, lb / day
Nutrient Requirements 10 Energy Required for 1.5 lbs ADG in 150 d grazing season Mcal / day 8 6 4 2 NEg NEm 0 500 550 600 650 700 750 Calf weight, lb / day
Heat stress and maintenance Mcal NEm / day 10 9 8 7 6 5 4 3 2 1 0 +4.2% +6.2% Stocker +9.8% +13.4% 60 degrees 70 degrees 80 degrees 90 degrees 100 degrees
Nutrient Requirements Other things that effect energy requirements of cattle Growth Potential/efficiency Gender Intact males have 15% greater maintenance energy requirements Fat deposition versus protein deposition Growth promotants Implants Ionophore
Nutrient Requirements Protein Rumen Degradable protein = RDP Rumen microbes use to form microbial protein Sources Forage, feed, recycled, non protein nitrogen Deficiency leads to decreased fiber digestion Rumen Undegradable protein = RUP By-passes rumen, absorbed in lower tract Crude Protein = N%*6.25
Nutrient Requirements Protein Metabolizable Protein Microbial Protein + RUP Requirement 3.8 g MP / kg EBW 0.75 Lush spring pastures that are high RDP low in fermentable carbohydrates Could produce excess Urea Add energy to detoxify Urea
Feeding Strategies The animal is consuming a ration and it should meet nutrient requirements for Maintenance Production Test your soil and forage and know what your basis is Determine animal requirements Varies based various factors
Feeding Strategies Determine if the ration fits the animals requirement Identify deficiencies and supplement to meet those need
Feeding Strategies Stage of Production Calving to breeding Breeding to weaning Mid gestation Late Gestation Nutrient requirements Highest Moderate Lowest High
Feeding Strategies Late gestation Cattle Dry matter intake 1.9 to 2.0% body weight Fetal Growth Mange to have BCS 5-6 prior to calving
Feeding Strategies Early Lactation Cattle Dry matter intake 2.4 to 2.6% body weight High nutrient need Milk production Repairing the reproductive tract Lack of nutrients could limit these processes Watch cattle condition closely 1 st calf heifers
Feeding Strategies Late Lactation Cattle Dry matter intake 2.2 to 2.5% body weight Watch BCS of the cows Below 4 consider early weaning Creep feeding
Feeding Strategies Body Condition Score 4 Body Condition Score 6 http://www.cowbcs.info/photogallery.html
Feeding Strategies Creep feeding Beneficial when performance limited by Forage quality Forage quantity Milk production Range in creep feed conversions 5:1 to 30:1 Rule of thumb ~ 10:1 Lusby and Gill, Beef Cattle Handbook
Feeding Strategies 14.8% CP 28.2% fiber 53.2 % TDN Low fiber Easily digested Dr. Tom Troxel University of Arkansas 5.1 % CP 31.5% fiber 53.7% TDN Very low protein decreased digestibility 8.8% CP 32.8% Fiber 46.3% TDN Low energy
Feeding strategies Growing cattle Dry matter intake 2.5 to 3.2% body weight Target 2 lbs ADG Meet requirement for Maintenance Growth Forage affects performance Availability Quality Growth promotants Ionophores and implants
Feeding Strategies Supplemental Macro Mineral Levels Nutrient Mature High Mag Growing Salt, % 25 25 25 Calcium, % 12 10 10 Phosphorus, % 6 6 6 Magnesium, % 2 10 1 Potassium, % 0.5-0.5 2-4 oz / head / day intake
Feeding Strategies Supplemental Trace Mineral Levels Nutrient Mature High Mg Growing Copper, ppm 1500 1000 1000 Manganese, ppm 3000 2000 2000 Zinc, ppm 3500 3000 3000 Iodine, ppm 60 50 50 Cobalt, ppm 12 10 10 Selenium, ppm 12 10 10 2-4 oz / head / day intake
Feeding Strategies Supplemental Vitamin Level Cows, IU / lb Calves, IU / lb Vitamin A 250,000 125,000 Vitamin D 25,000 12,500 Vitamin E 100 100
Feeding Strategies Salt Supplementation 25% salt provides 50-100% of daily need Requirement 0.6 oz growing 1.2 oz lactating When mineral intake is excessive mix salt with mineral 38
Feeding Strategies Phosphorus supplementation Calcium to Phosphorus rations 2 to 1 Forage phosphorus levels less than the following require supplementation 0.18% dry cow 0.27% lactating cow 0.27% growing calf Feeding 3 lbs of DDGS is equal to 4 oz of 10% phosphorus mineral 39
Feeding Strategies Phosphorus supplementation P concentration is greater when Plant is vegetative Animals can selectively graze Consider P supplements when Low soil fertility Drought stress Frosted forage 40
Feeding Strategies Magnesium Supplementation Grass tetany caused by Excessive K in lush forage Difficulty mobilizing bone Mg Excessive non-protein nitrogen supplements Low calcium intake Provide High Mg mineral 30 days prior to green up 41
Feeding Strategies Potassium supplementation Weathered forages are low in K Utilize a 0.5 to 0.8% K mineral to supplement forages Remove K supplementation during early spring through fall 42
Feeding strategies Vitamins A, D and E need supplementation on dormant or weathered forages D is usually met through direct sunlight and conversion through the skin or consumption of sun cured roughages
Fescue Toxicity Caused by endophyte that lives in the fescue plant Concentrated in the seed head Symptoms Loosing ends of tails, poor conception rates, low pasture gains, low milk production, heat stress Summer
Fescue Toxicity Ways to reduce symptoms Moves to warm season pastures in the summer Interseed legumes Supplement with other feed stuffs to dilute effect Graze or cut fescue before it gets to the seed head stage
Conclusion When feeding cattle think about The bugs They have requirements maintenance and production requirements they vary so determine them and feed accordingly Grazing your pastures when they are higher quality leads to better animal performance Less supplementation to meet requirements
Conclusion Use your tools Testing feedstuffs Soil test BCS to identify needs of the animal Looking at the feces Manage your cattle, pastures and feedstuffs to keep fescue toxicity from happening
Questions Contact Information Dr. Patrick Davis, Livestock Specialist University of Missouri Extension Johnson County 135 W. Market, Warrensburg, MO, 64093 PHONE: 660-747-3193 FAX: 660-747-9867 E-MAIL: davismp@missouri.edu WEB: extension.missouri.edu/johnson