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1 Nutri&onal influences on fer&lity: fescue, energy and protein Energy Protein Mark A. McCann Extension Animal Scien&st Virginia Tech Fer&lity Impact of Energy and Protein on Pregnancy Rate Calve with adequate nutri&onal reserves Maintain or gain weight prior to breeding Based on nutrient amount consumed Johnson and Funston, 2013 Most of our green grazed forages meet protein requirements Visual measure of nutri&on Body condi&on score (Kunkle et al., 1998). Staunton, Virginia 1

2 Body Condition at Calving and Heat after Calving Body condi&on score and return to estrus Days After Calving Body Cond. No. of at calving Cows % Showing Heat Thin Moderate Good From: Whitman, R.W. (1975). Ionophores/Rumensin Decrease age at puberty in heifers Improve feed efficiency and total winter feed consump&on in cows Reduce post- partum interval 5-46 days (Johnson and Funston,2013) Increase calving rate (Bailey et al., 2008) Effect can be limited by low quality forage Bailey et al Arkansas- Bermudagrass pasture and hay Two year study uolizing 248 cows Rumensin supplemented in daily- fed mineral mix at 200mg/hd SupplementaOon began ater calving and cononued for 42- d Rumensin level, mg/d PPI Calving % Energy Fescue Protein Tall Fescue pasture and hay " 90% of tall fescue fields in southeastern U.S. infected by wild-type toxic fungus " Consumed by cattle, horses, sheep Fer&lity Staunton, Virginia 2

3 Tall fescue toxicosis Fungus = Endophyte Fescue alkaloid level as affected by preserva&on Endophyte enhances plant persistence drought tolerance insect resistance " Endophyte produces ergot alkaloids which are livestock toxins Plant Benefits VS " Alkaloids are lowest during periods of dormancy (midsummer and winter) Animal Effects Roberts et al., 2002 Effect of Nitrogen Fer&liza&on on Ergovaline Levels Ergovaline, ppb Lbs/acre Leaf blades Stems Seed heads Fescue seed head suppression Grazing management Clipping Chemical- Chaparral (2oz/acre) Suppresses seed and stem development Yellows forage Reduces available forage Remaining forage is of higher quality Kills clover Fescue Toxicity and Performance Measurements Serum prolactin Rectal temperatures Behavior Average daily gain Gain per acre Dry matter intake Available forage Friendly Endophytes A]empt to Take the Best from both E+ and E- Remove Toxic Endophyte Add a Nontoxic Endophyte Toxic Endophyte Endophyte Free Novel Endophyte R. Kallenbach, University of Missouri Staunton, Virginia 3

4 Friendly = Non- toxic= Novel Naturally occurring Agronomic benefits No animal toxicity Combines the best of both Temperature Data Loggers IN SUMMER HEAT: Body Tem peratures of Cattle Grazing MaxQ or Toxic Tall Fescue during Summer IN WINTER COLD: Body Temperatures of Cattle Grazing MaxQ or Toxic Tall Fescue during Winter Body Temp, o F :00 8:30 11:00 13:30 16:00 18:30 21:00 TIME 23:30 2:00 4:30 TOXIC MaxQ Air Temp Air Temp, o F Body Tem p, o F TIME MaxQ TOXIC Air Temp Air Temp, o F Watson et al., 2004 Watson et al., 2004 Fescue Impact on Reproduc&on Impact on the bull Effect on the male Effect on the female Decreased performance Elevated body temperature Li]le impact on scrotal circumference Li]le impact on semen mo&lity & morphology Reduced fer&liza&on ability of the semen Effects occur before day 7 Staunton, Virginia 4

5 Impact on the cow Percentage of embryos reaching blastocyst stage recovered on d- 7 afer estrus Elevated Body temperature Reduced prolac&n Decreased cow and calf performance Reduced pregnancy rate Decreased embryo quality Decreased embryo development Embryo development effects occur before day 7 Schuenemann et al., 2005 Percentage of embryos of transferable quality recovered on d- 7 afer estrus Can we manage around fescue? Schuenemann et al., 2005 Effect of Calving Season and Strategic Use of renovated Fescue Pastures 100% infected fescue vs 75% infected + 25% friendly fescue Friendly fescue grazed during breeding season and prior to weaning Spring vs fall calving season Spring only 100% friendly fescue Cow- calf performance F 100 S 100 F 75 S 75 Friendly Breeding wt Δ, lbs Calving rate, % Weaning wt, lbs HiMag4 cul&var (Caldwell, et al 2013) (Caldwell, et al 2013) Staunton, Virginia 5

6 Mi&ga&on Strategies DiluOon- clover, other forage species, feed RenovaOon- Friendly endophyte Seed head suppression- grazing mgt/ chemical Calving season? Ques&ons Staunton, Virginia 6