Developing Replacement Heifers for the Beef Herd

1. Developing Replacement Heifers for the Beef Herd

2. Cow Herd Reproductive Efficiency Impacts Annual Gross Income • Fertility 5 times more important than growth rate. • Growth rate twice as important as carcass characteristics. • Infertility 5 times more important than respiratory diseases in affecting profitability within beef cattle industry.

3. Heifer Management is the Cornerstone of Cow/Calf Production • Heifers are expensive whether raised or purchased. • Management of first-calf heifers affects lifetime productivity. • Lower rebreeding rates for heifers (as a group) considered normal through 2nd calf. • Heifers have unique challenges compared to mature cows. • Uniform calf crops begin with controlled breeding seasons and well developed heifers.

4. How Many Heifers Should I Keep?

5. Replacement Heifer Numbers • Match numbers to available resources. • North Dakota State University research suggests replacement rate for “typical” cow herd is 17%. • Previous research indicates one-half of heifers reaching 55% of mature weight were cycling by first breeding season. • Ninety percent of heifers will be cycling by first breeding if they reach 65% of their mature weight prior to breeding. • Research suggests saving 10-50% more heifers to breed than the producer thinks he will need.

6. Replacement Heifer Numbers • Match numbers to available resources. • North Dakota State University research suggests replacement rate for “typical” cow herd is 17%. Average Cow Age Distribution Percent of Cows in Herd Percent Age in Years

7. Creep feed or not creep feed? • Excessively fat heifer calves can have reduced milking ability during their lactation. • High protein creep feed (Oklahoma Silver), and post-weaning supplement (Oklahoma Gold) can increase weight gain without “over conditioning”

8. Replacement Heifers and Implants • Not recommended for “designated” replacement heifers. • No decrease in dystocia in implanted heifers compared to non-implanted heifers. • Some studies indicated a slight reduction in fertility. • Implanting at birth or close to puberty reduced reproductive performance • Implanting younger and lighter heifers once at 2-4 months of age will not reduce reproductive performance. • Do not reimplant heifers selected to be bred.

9. Implants in Potential Replacement Heifer Calves • NO ADVANTAGE in puberty age, milk, or dystocia rate due to calf hood implants • Heifers that are known to be replacements; No need to implant • Consider implanting smaller, younger half of the heifer crop • Do not reimplant heifers selected to be bred

10. Immunization Strategies • Consult local veterinarian on detailed vaccines recommended for your area: ASK ABOUT THESE: • Blackleg, and Malignant Edema --2-4 months of age. • Brucellosis vaccine -- 4-10 months of age. • 3-4 weeks prior to weaning and/or at weaning: IBR, BVD, PI3, 7-8 way Clostridial, Leptospirosis, Campylobacter, and deworm. • Booster vaccines may be needed 3-4 weeks following the first injections. • Yearling boosters : BRD vaccines (30 days prior to breeding if mlv vaccine.), clostridials, and begin annual Lepto. and Campylobacter injections

11. Growing from weaning to breeding • Must weigh 65% of mature weight • Gain program needs 1.0 to 1.5 pounds per day Example: Heifer weaned Nov. 1 at 525 (500) Must weigh on April 10 747 (65% of 1150) 222 pounds in 161 days = 1.38 pounds per day OR 247 pounds in 161 days = 1.53 pounds per day • Group heifers of common age and weight together • young light heifers • older larger heifers

12. Weaning to Breeding Issues (cont.) • Puberty is affected by age, weight, breed and adverse environmental stresses. • Heifers must attain 65% of their mature weight by their first breeding season to be cycling, and breed successfully.

13. Growing Programs Research “Timing” of gain research conducted independently by KSU, and OSU show similar results. KSU OSU researchers gained heifers at 0.6 lb./day over the winter, and then 1.92 lb./day in the spring and showed that those heifers reached puberty 20-30 days sooner than the control heifers which were gained at a continuous rate over the entire feeding period. Overall pregnancy rates were similar.

14. Wheat Pasture Growing Program (post-breeding) • Allow bred heifers limited access to wheat pasture such as every other day, or 1 day on and 2 days off. • Limiting access of wheat pasture for bred heifers will help prevent over-conditioned heifers and possible dystocia problems at calving.

15. Ionophores in Growing Programs Monensin, and Lasalocid feed additives approved for growing programs for replacement heifers. % Cycling Texas and Wyoming research indicates that heifers consuming 200 mg. of Monensin per head per day reached puberty at an earlier age than heifers not consuming Monensin in feed supplements. Monensin fed Non-Monensin fed Days

16. Culling Decisions after Breeding • Pregnancy test heifers 60 days after removing the bulls. • Cull all open heifers immediately after testing. • Lifetime studies show 55% reproductive rate for sub-fertile heifers that failed to conceive after their first breeding season. • Immediate culling will reduce the winter feed bill. • Immediate culling will allow marketing them as feeder heifers at higher market prices (age/perceived public health issues, etc.)

17. Price of keeping open replacement heifers 2004 prices of open replacement heifer 950 @ $90/cwt = $855.00 2004 prices of open two-year old cow 1075 @ $66/cwt = 709.50 145.50 loss Not including expenses

18. Body Condition at Calving Research proves those cows that maintain adequate body condition to calving, return to estrus sooner. Cows in thin body condition at calving return to estrus slowly, usually not in time to calve within a year. Therefore the target is:

19. At Calving (as 2) 85% of mature weight body condition score = 6

20. Body Condition, Birth Weight and Percent Dystocia in 2 yr. Old Heifers (OSU) BCS at Calving 4 (thin) 5 (average) 6 (good)) Birth wt 68.3 66.2 67.6 60.8 68.0 71.8 % assist 33 32 35 % rebred 65 78 89

21. What about thin heifers at calving? • OSU study divided 81 heifers into 2 groups in November: 1 group lost body condition until calving, the other maintained body condition until calving. • At calving they were further divided to either (1) gain weight and body condition postpartum, or to maintain body condition postpartum.

22. Thin Heifers at Calving (cont.) • Thin heifers at calving which were allowed to gain weight and condition through breeding had a rebreeding rate of 66%. • BCS 5 or better heifers at calving which were allowed to maintain condition through breeding had a rebreeding rate of 91%.

23. Thin Heifers (cont.) • Heifers fed to gain weight and condition received 28 lb./hd./day of a 12% CP grain mix at $0.073/lb. for a total cost of $141. • The improvement in reproductive rate (66% vs. 36% pregnant) of the thin heifers was not enough to offset the feed expense. BODY CONDITION AT CALVING IS THE KEY!!

24. Predicted number of days from calving to first heat Condition score at calvingCondition score change after calving to day 90 -1 -0.5 0 0.5 1 1.5 2 3 189 173 160 150 143 139 139 4 161 145 131 121 115 111 111 5 133 116 103 93 86 83 82 5.5 118 102 89 79 72 69 66 The data shows young cows that calve in thin body condition (BCS 3 to 4) cannot gain enough body condition postpartum to match the rebreeding rates of moderately conditioned (BCS 5.5) cows that maintain or lose very little condition postpartum.

25. Sorting Heifers from Cows • First calf heifers are usually the most difficult to get rebred for reasons such as growth requirements, calving, lactation, involution and repair of the reproductive tract, limited dentition, and rebreeding. • They are additionally subjected to “bossing” and abuse by larger, mature cows when fed together, and cannot gain on the lower quality forage the mature cows consume.

26. Sorting (cont.) To provide heifers a chance to achieve the same reproductive efficiency as the mature cows, they often need to be sorted off to themselves and treated separately as a group

27. Summary • Properly immunize heifers at 2 months, weaning, and at 1 year of age according to a veterinarian’s recommendations. • Heifers must reach 65% of their mature weight by the start of the breeding season. • The most economical growing program for replacement heifers is going to utilize standing or harvested forages as a major portion of the diet. Heifers may be grown slowly then given higher energy feed to accelerate the rate of gain to achieve the required 65% of mature size by the start of the breeding season

28. Summary (cont.) • Utilize the highest quality hays and/or the best pastures because young cattle cannot utilize low quality roughage as well as the mature cows. • Use an ionophore to improve feed utilization and hasten the onset of puberty. • Breed replacement heifers 3 to 4 weeks ahead of the adult cows.

29. Summary (cont.) • Cull all open heifers after the first breeding season. • Grow bred heifers adequately so that they are in the body condition score 6 at calving time. • Sort young cows (2 and 3 year olds) from older cows to insure adequate feed intake for young, growing, but smaller cows.

30. Questions?