1 / 29

Development of Replacement Heifers

Development of Replacement Heifers. Oklahoma Cooperative Extension Service Oklahoma State University. Cow Herd Reproductive Efficiency Impacts Annual Gross Income. Fertility 5 times more important than growth rate. Growth rate twice as important as carcass characteristics.

garymiller
Download Presentation

Development of Replacement Heifers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Development of Replacement Heifers Oklahoma Cooperative Extension Service Oklahoma State University

  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.

  4. Heifer Management is the CornerStone of Cow/Calf Production (continued) • Heifers have unique challenges compared to mature cows. • Uniform calf crops begin with controlled breeding seasons and well developed heifers.

  5. How Many Heifers Should I Keep?

  6. 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.

  7. Avoid Excessively Fat Heifers • More of a problem in purebred, seed stock, and herds using dairy stock as recipients of ET calves. • Excessively fat heifers can have reduced milking ability during their lactation. • Monitoring body condition on heifers can prevent the problem. • 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. Immunization Strategies • Blackleg, and Malignant Edema vaccines at 2-4 months of age. • Brucellosis vaccine at 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. Consult local veterinarian on detailed vaccines recommended for your area.

  10. Immunization Strategies(continued) • Booster vaccines should be given 3-4 weeks following the first round of injections. • Yearling booster vaccination with BRD vaccines (if using a modified live virus vaccine, and then annual Lepto. and Campylobacter injections 30 days prior to breeding.

  11. Weaning to Breeding Issues • Most heifers weaned at 7-10 months of age, weighing from 350-650 pounds. • Size, age, and extra nutritional demands suggest that heifers should be separated from mature cows and fed to gain 1.25-1.5 pounds per head per day. • If there is considerable variation in weight and age of heifers, divide them into smalls, and larges, and feed separately to gain appropriately.

  12. Weaning to Breeding Issues(continued) • 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 researchers gained heifers at 0.55 lb. per day for first 5 mos., then 2.5 lb./day for last 2 mos. with reproductive performance results equal to heifers gaining 1.31 lb. per day for the entire 7 mos., and on 12% less feed. • 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.

  14. Wheat Pasture Growing Program (pre-breeding) • Heifers will gain 1.5 lb/day over the winter grazing period. • They will be ready to breed in April or May. • Set aside “graze-out” patch to get heifers to breeding season and avoid severe weight loss when pulled off wheat pasture.

  15. 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.

  16. Ionophores in Growing Programs • Monensin, and Lasalocid feed additives approved for growing programs for replacement heifers. • 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. • Stocker cattle gains are increased by 0.1-0.2 lbs. per head per day when fed 100-200 mg./hd/day of an ionophore in feed supplements. • Heifers would gain an additional 15-30 lb/hd over a 150 day growing period.

  17. 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.)

  18. Body Condition at Calving • Research proves those cows that maintain adequate body condition to calving, return to estrus sooner than cows that lost considerable condition prior to calving. • Body condition scoring (1 to 9 system) is more accurate in estimating stored energy reserves (fat) than weight measurements. • BCS accounts for 85-91% of the variation in stored body energy in cows, and can be easily used to monitor changes in body condition to facilitate management practices such as sorting, supplementation, etc. • Cows in thin body condition at calving return to estrus slowly, usually not in time to calve within a year.

  19. 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.

  20. Thin Heifers at Calving (continued) • 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%.

  21. Thin Heifers (continued) • Heifers fed to maintain weight and condition postpartum to breeding received 4 lb./hd./day of cottonseed meal at $0.13/lb. for 69 days for a total cost of $36 per head. • 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. • The results of this study concur with numerous other university experiment station studies.

  22. Thin Cows (continued) • 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.

  23. Thin Cows (continued) • Cows must be rebred by 85 days postpartum to calve again the same time next year. • None of the cows in thin condition recycled in time to maintain a 12 month calving interval.

  24. 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.

  25. Sorting (continued) • North Dakota State U. researchers recorded age and weight distribution of commercial cow herds over a 21 year period to illustrate the differences in sizes by age of the “typical” cow herd. • 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

  26. 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

  27. Summary (continued) • 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.

  28. Summary (continued) • 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.

More Related