Management and Supplementation Strategies to Improve Reproduction of Beef Cattle on Fescue John B. Hall Extension Beef Specialist Virginia Tech
Effects of Endophyte Infected Fescue on Reproduction in Cattle! Decreased pregnancy rates Cleavage failure Compromised sperm physiology Early embryonic mortality Reduced follicular growth Decreased progesterone production! Reduced or limited milk production
Strategies to Combat Effects of Fescue Supplementing Nutrients Energy Protein Minerals Mitigating Effects of Toxins Blocking physiological actions Changing calving seasons Reducing Exposure Grazing other forages Dilution of fescue with other forages or feeds Feeding adsorbents or detoxifying agents
Supplementing nutrients Consumption of E+ fescue decreases forage intake Energy is the limiting nutrient, but protein may also be needed Exacerbated by high environmental temperatures
Supplementing nutrients By-pass protein may or may not increase cow performance! Effective level of by-pass protein depended on source of energy - corn vs soyhulls (MO)! By-pass protein did not affect performance (U of IL)
Effect of Supplement Type on Heifer Pregnancy Rate! Heifers developed on E+ fescue! Received 1.0% of BW in supplement! Equal amounts of protein and energy % Pregnant 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 0! Gained 1.5 to 1.7 lbs/day A I Overall Soyhulls Cottonseed Corn/soy
Impact of High Fat Supplementation on Pregnancy Rates of Cows Grazing E+ Fescue 100 90 % P r e g n a n t 80 70 60 50 40 30 20 10 0 Corn-Soy Supplement Mix-30 (23% fat) Adapted from Myers et al., 2004
Mineral Supplementation Mineral requirements of cattle are dependent on physiological status Lactating vs. dry Growing vs. mature Mineral content of forage is dependent on: Soil fertility Forage type and maturity
Mineral Supplementation Animals consuming fescue Have decreased immune function May have impaired absorption of phosphorus There appears to be no magic fescue mineral but Increasing levels of trace minerals related to immune function may be beneficial Mineral intake needs to be monitored closely
Minerals supplement - Commercial Mineral Salt 15-30 Calcium 0-12 Phosphorus0-12 Percentage Magnesium 0-4 (8-14) Sulfur 0-3
Mineral Supplements - Commercial Mineral Amount Zinc 0.18-0.36 % Copper 0.10-0.25 % Manganese0.18-0.36 % Iodine Selenium 2.6 ppm 52+ ppm
Pregnancy Rates in Spring or Fall Calving VA DOC Herds % P r e g n a n t 100 95 90 85 80 75 70 65 60 55 50 2003 2004 2005 2006 Fall Spring
Comparison of Pregnancy Rates in Spring and Fall Calving Herds Fall Line Operation 100 % 95 90 P r e g n a n t 85 80 75 70 65 60 55 50 633 / 668 861 / 1001 Spring had an 8.75% lower pregnancy rate. That s over 87 calves! 3-year Average Fall Spring
Stockpiled Fescue! Graze off field! 60 units of N - Aug.! Don t graze til after frost! Grazing from Nov-Feb! High quality - 60+ % TDN 10-12 % CP! Low Cost - High Value! Use strip grazing
Utilizing Stockpiled Forage! Always utilize grass-legume mixture first! Strip graze maximizes utilization only enough forage for 7-14 d no back fence needed
vs
Cattle selection for fescue Using a fescue tolerant bull did not affect performance of calves (VPI&SU) Brahman and Brahman X cattle had increased milk production and weaning weights on fescue than Angus (UARK)
Impacts of selection! There are tolerant cattle eliminate fescue queens! Care in selecting bulls from non-fescue regions! Breed used must not only perform on fescue, but needs to perform in feedlot and meet regional market
Impact of TASCO mineral on Pregnancy Rates in Cows Grazing E+ Fescue P e r c e n t P r e g n a n t 100 90 80 70 60 50 40 30 20 a a a b a b 10 0 162 64 67 101 102 55 69 63 67 87 64 52 1 2 3 4 5 6 Farm Control Tasco
Effect of Supplement on Cow/Calf Performance on E+ Fescue 5 2 0 5 0 0 4 8 0 L b s. 4 6 0 4 4 0 FEB-200 Control Corn Suppleme 4 2 0 4 0 0 Weaning Weight
Effects on Cow-Calf Pairs - OH 4 5 0 4 0 0 3 5 0 3 0 0 2 5 0 WW, lb 2 0 0 1 5 0 1 0 0 5 0 0 Supplement FEB-200 Control
Summary! Fall calving is the most powerful management tool! Supplementation with fiber based feeds can offset some of the effects of E+ fescue! Increasing amounts of Cu, Se, Zn appears to be important! No magic bullets but some interesting possibilities