Nutrition and Reproduction in Beef Cows Cattlemen’s College January 29, 2003 David Lalman Oklahoma State University

The Big Picture Genetics and yesterday’s nutritional environment determines today’s body condition. Adaptation and body condition at calving influence tomorrow’s reproductive success.

Body Condition Score at Calving and Pregnancy Rate Body Condition of Cows and Heifers at Calving

Predicted number of days from calving to first heat Condition score at calving Condition score change after calving to day Difference = 28 days Lalman et al., 1997

Predicted number of days from calving to first heat Condition score at calving Condition score change after calving to day Difference = 16 days Lalman et al., 1997

Heifer Weights at and After Calving and Pregnancy Rate Weeks after Calving 36% 66% 91% 94%

Moral of the BCS Story Achieving moderate body condition at calving is more effective than making up body condition after calving. Playing “catch up” is almost always expensive and usually not practical.

Achieving Moderate BC Genetics Grazing conditions Early (or earlier) weaning Limit feeding concentrates Protein and (or) energy supplementation during fall and winter…prior to calving

Fat Supplementation and Beef Cow Reproduction Limited research including performance data. Considerable work currently being conducted on this topic. There are MANY factors to consider.

Fat Supplementation Factors to Consider Timing of supplementation Fat source Amount to supplement Cow age Cow condition Historical reproductive rates Cost effectiveness

Effects of Fat Supplementation on Pregnancy in Beef Females Cow Sup Amount Fat Trt VS Con Author Age (No.) Timing Fed (lb) Source Pregnancy Espinoza Cow (67) -61 to Megalac 91 vs 84 * Indicates a significant difference at P < 0.1 Lammoglia Hfr (52) -53 to Clv.7 Safflower *75 vs 57 Bellows Hfr (52) -65 to Clv.55 Saf, Soy, Sun *94 vs 79 Bellows Hfr (41) -68 to Clv 1.1 Sunflower 80 vs 90 Johnson Cow (67) -64 to Clv.78 Sunflower 95 vs 95 Alexander Cow (48) -59 to Clv.25 Sun & Soy 91 vs 88 Graham Cow (??) -45 to Clv.56 Soybeans 93 vs 86

Effects of Fat Supplementation on Pregnancy in Beef Females Cow Sup Amount Fat Trt VS Con Author Age (No.) Timing Fed (lb) Source Pregnancy De Fries Cow (20) Clv to Est.33 Rice Bran *94 vs 71 * Indicates a significant difference at P < 0.1 Filley Hfr (19) Clv to 30.5 Megalac 72 vs 68 Burns Hfr (41) 61 to Fishmeal 85 vs 90 Johnson Cow (67) Clv to Sunflower 95 vs 95 Graham Cow (??) Clv to AI.56 Soybeans 87 vs 86 Beckmeir Cow (96) Clv to 125 ?? Soy oil 83 vs 83 Burns Hfr (25) 50 to Fishmeal No diff

Fat Supplementation Summary Fat supplementation has improved pregnancy rates in 3 out of 14 studies reviewed. Marginal responses may be due to adequate body energy stores or adequate basal diet nutrient availability Expect greater response with thin cows or when nutrient availability is low (drought, late-winter calving)? Response seems to be greater when overall pregnancy rates are low. Potential for improvement in 1 st service conception

Program Feeding Concentrates to Replace Hay Corn may be the lowest cost energy source for cattle in some drought areas.

Program Feeding for Calves 80% whole shelled corn 20% commercial supplement (38 to 44% protein) including high calcium and ionophore Feed 80/20 mix at approximately % of body weight No hay or pasture ADG = Requires intensive management, equipment and facilities

Program Feeding McCullum and Gill, 1991 Steers, initial weight = 463 lbs 84 d wintering study Treatments Dry wintered with 2 lb supplement Target gain of 1.0 Target gain of 1.5 Target gain of 2.0

Program Feeding Results Wintering Regimen Dry W ADG Avg DM intake Feed/Gain Feed $/Gain a - $.27$.25$.24 a Feed cost = $110 per ton Gill et al., 1991, OSU An. Sci. Res. Report

Program Feeding, Cont’d In adequate volume most Oklahoma Feed Manufacturers can make these supplements for you Supplements should be pelleted Not an easy fix Takes much more labor Requires more intensive management

It can work for cows too! Goal is usually maintenance Include small amount of hay for safety Example diet: Corn9 lbs. Grass hay3 - 7 lbs. Supplement2 lbs

Cow Example Cost of free choice avg quality hay ($65 per ton) + 2 lb. protein = $1.04 Cost of limit fed corn program at current costs = $.80 Does require more labor and management skill

Whole VS Cracked Corn for Limit Fed Cows ItemCrackedWhole Corn Corn ADG BCS change Calf ADG From Tjardes, 1998, J. Anim. Sci., 76:8

Program Feeding Bred Heifers HayCornWMSHBMS Hay Sup Feed Total TDN CP

Program Feeding Bred Heifers HayCornWMSHBMS ADG $/Day $/lb gain Hay = $60/ton, Sup = $190/ton, Corn = $2.40/bu, WMSH = $137/ton, BMS = $90/ton