Feeding Weather Damaged Forage to Beef Cattle

1. Feeding Weather Damaged Forage to Beef Cattle Juanita Kopp, Ph.D., P.Ag. Manitoba Agriculture, Food & Rural Initiatives Farm Production Extension Specialist – Beef Livestock Knowledge Centre P.O. Box 180, 8 Fraser St., Pilot Mound, MB Cell: 204-825-4302 Juanita.Kopp@gov.mb.ca

2. What is weather damaged forage? • Weathered due to: • Excessive sun exposure • Over drying • Precipitation • Rain leaches the most soluble nutrients • Loss is greatest with the higher quality forages • Leaching loss can be as high as 15% of the total DM • Moulds & other microbes greater growth during wet weather, these organisms utilize the most nutritious portions

3. Weathered Forage • Forage in a windrow harvested too late or rained on • Lower energy • Lower protein • Heat damaged • Moulds • Mycotoxins • Forage species, growing conditions & stage of maturity affect nutritive value

4. Once cut--rain, rain--Go Away • Each rain event can have an affect on quality • The closer to fresh forage the less damage • Within a few hours very little damage is done • As the length of time increases from cutting to when it rains, losses increase

5. Utah research found • Alfalfa receiving 1” of rain 3 hours after cutting lost ~ 2% of CP yield & 3.7% DM yield compared to alfalfa with no rain • If the rain fell 12 hours after cutting, CP yield was reduced 3.5% & DM yield was reduced 5% • As the amount of rainfall increases, losses increase • Alfalfa that received 0.2” of rain yielded about 5% less dry matter & 4% less CP/acre than hay that received no rain • When the amount of rainfall increased to 0.8 inches, DM yield & CP were reduced by 10%

6. As a general rule, the loss in quality & yield due to a 1” rain event will exceed the losses in quality caused by allowing alfalfa to mature an additional week • This is not true for grasses since the decline in quality due to maturity is much more rapid than it is for alfalfa

7. Rainfall effect on energy content of hay

8. Loss of nutritive value with advancing maturity • Decreased proportion of leaves & the corresponding decrease in protein • Legumes – 70% of protein in the leaves • Increased proportion of stem & the corresponding increase in fibre  • Increased lignification of the stem & the corresponding decrease in energy value

9. Fisher, L.J. 1980

10. Heat damaged protein • Brownish colour –useful protein content 80% of original value • Dark brown or black –less than 50% of protein may be digestible • ADIN

11. Maturity effects on forage quality of alfalfa & quackgrass NDSU 1993

12. RFV Lactating Cows Backgrounders Replacement Heifers Beef Cow

13. Crested Wheat Grass quality during the grazing season

14. Theoretical amounts of DMI required to meet the energy (TDN) requirements of a 1200 lb lactating beef cow (20 lb milk/d) when grazing Crested Wheat Grass with different protein and energy concentrations

15. Forage Intake Guidelines as a percent of body weight

16. Feed Test!!!!

17. Beef Nutrition

18. Cattle Need: • Water • Energy • Protein • Minerals • Vitamins

19. Cattle Nutrition • Nutrient requirements of cattle change throughout the year based on the stage of the production cycle • Age • Sex • Breed • Level of activity • Pest load • Environment • All these factors have an additive effect on the nutrient requirements

20. Nutritional Priority: Where the Feed Nutrients Go Alive & moving Including weight gain Milk for calf Requirements increase Heat cycles & conception Fat deposition

21. Protein • Third most important dietary component • “Building Blocks” of the body • Degradable intake protein (DIP) requirements need to be met for microbial growth first • Then & only then consider bypass protein or undegradable intake protein (UIP) • Manage for heat damaged protein if hay/feed baled too wet ADIN!!!

22. Energy Requirements (TDN %) for Beef Cattle

23. Crude Protein (%) Requirements for Beef Cattle

24. Energy & Protein Supplementation • Needed when feeding: • Slightly over-heated hay • Denatures protein, molds use sugars • Browning of forage • Carmalized sugars, tobacco smell • Rained damaged hay • Poor quality hay, straw

25. Energy Supplements

26. Grain supplementation Cowbytes Ration Guidelines

27. Protein Supplements

29. Moulds

30. Mould • Estimated to reduce feed value by at least 10% • Vitamins destroyed • Vitamins A, D, E, K & thiamine • Mould requires oxygen, heat, moisture & nutrients to grow • Moulds grow rapidly at 75 to 90◦F • Above 15% moisture

31. Mouldy Feeds • Very dusty • Mold organisms & spores • Inhaled dust • fungal pneumonia • Some spores may pass through lesions in rumen wall & carried to blood stream • Settle in the uterus • uterine infections & mycotic abortions

32. Mouldy Feeds • Estrogenic metabolites may affect lactation & cycling • Do not give mouldy feeds to pregnant or lactating cows • Dilute moldy feed with good quality feed • reduce potential for problems when feed non-pregnant, dry, older animals • Supply adequate levels of Vitamin A

33. To utilize weathered forages • FEED TEST!!! • Supplement for deficiencies in energy & protein • Balance rations • Feed vitamins & minerals • Check for mineral interactions • Ca:P, K/Mg+Ca, S

34. Questions???