Unit 10: Beef Cattle Chapters 25 & 26
Objectives • Understanding of the approaches to improving cattle performance through feeding, environment, management, genetics • Knowledge of various management practices associated with cow/calf, feeder, and finishing • Discuss the role of environmental management in cattle feeding • Investigate the economic picture of the beef industry
Introduction • >250 breeds identified • 100’s others not identified w/ a breed name • Breeds distinguished by: • Color • Color pattern • Polled/horned • Extreme differences in form or shape
Introduction • Purebred cattle • What does it mean to be purebred? • Major U.S. breeds • Early 1900’s Shorthorn, Hereford, and Angus were primary breeds • Today >60 breeds available • <20 have widespread impact on the national herd
Introduction • Registration numbers • Angus, Limousin, Simmental, Hereford are the most common in regard to registrations • Breeds • http://www.ansi.okstate.edu/BREEDS/index.htm
Improving Beef Cattle through Breeding Methods • Selected animals that are superior to herd average • Selecting traits that are highly heritable
Traits and their Measurement • Economically important traits • Reproductive performance • Weaning Weight • Postweaning Growth • Feed Efficiency • Carcass Merit • Longevity (functional traits) • Conformation • Freedom from genetic defects
Traits and their Measurement • Reproductive Performance • Goal of >85% of calves weaned • Calf every 365d or less • Entire herd calving season <90d • Fertility is not highly heritable (~20%) • High heritabilities for: • Birth wt. ~40% heritable • Scrotal Circumference ~40% heritable (>32cm) • Increased SC produce more semen • Half sisters that reach puberty earlier • Best way to improve reproductive performance is to improve environment
Traits and their Measurement • What 2 ways can we improve environment? • Select bulls that are reproductively sound • Performance can also be improved by crossbreeding • Weaning Wt. • Measured by actual wt. • Reflects milking & mothering ability of dam • Preweaning growth rate • ww is commonly adjusted to 205d equivalent to account for variance in age of calf/dam • ww are commonly expressed as ratio to the other calves in the group
Figure 25.1 Variation or differences in weaning weight in beef cattle. The variation shown by the bell-shaped curve could be representative of a breed or a large herd. The vertical line in center is the average or the mean, which is 410 lb. Note that the number of calves is greater around the average and is less at the extremely light and extremely heavyweights. Source: Colorado State University.
Figure 25.2 Comparison of breed averages and the variation within each breed for weaning weight in beef cattle. The vertical lines are the breed averages. Note that some individual animals in breeds B and C can be lower in weaning weight than the average of breed A. Source: Colorado State University.
Traits and their Measurement • Weaning weight can be selected for (~30% h) • Postweaning Growth • Weaning from finished wt. • Usually they are very efficient • Weaning wt. and postweaning growth often combined to one trait • Adjusted 365d wt. • (160 * ADG) + adjusted 205d wt. = Adj. 365d wt. • ADG & Ad 365d wt. highly heritable (~40%)
Traits and their Measurement • Feed Efficiency • Lbs. feed/lb. gain • Can be misleading • Hard to measure • Differences in production goal • High heritability ~45% • Carcass Merit • Quality grades and yield grades • Can measure by ultrasound or by visual analysis • Highly heritable >30%
Traits and their Measurement • Longevity • Important, especially for cows • Bulls may be kept 3-5 yrs. • Highly productive cows 4-15 yrs. • Reasons for culling • Skeletal unsoundness • Poor udders • Eye problems • Lost/worn teeth • Few cows highly productive >10yrs.
Traits and their Measurement • Conformation • Form, shape, visual appearance • Source of controversy • Traits are medium to high heritability (30-60%) • Genetic Defects • Usually occur infrequently • Common defects • Double muscling • Slow growing, poor fat deposition • Syndactyly (Mule Foot)
Traits and their Measurement • Osteoporosis (Marble Bone Disease) • Short lower jaw, protruding tongue • Hydrocephalus • Bulging, fluid filled head • Arthrogryposis (Palate-Pastern Syndrome) • Pastern tendons contracted • Upper part of mouth not fused together • Dwarfism • Many of these result in death early
Bull Selection • Bull selection accounts for 80-90% of genetic improvement over time • Record accuracy is much higher due to number of offspring • Most progressive seedstock producers record ( on their bulls): • Birth wt. • Weaning wt. • Yearling wt.
Bull Selection • Breeding Values • Phenotype determined by genotype + environment • Genotype determined by two factors: • Breeding value (what genes are present) • Nonadditive value (how genes are combined) • Values are collected and analyzed by computer by breed organizations • EPD’s are used to express these values
Bull Selection • Sire Summaries • Data that has made sire selection much more accurate & effective • Published by most breed associations • Measurements by EPD’s and ACC (Accuracy) • EPD • Birth wt. • Milk • Weaning-growth • Maternal • Yrlg. Wt.
Bull Selection • ACC • Measures expected change in the EPD as more progeny data is available • >.90 very little expected change • <.70 might change dramatically • Must be careful about stacking pedigrees
Selecting Replacement Heifers • Select more than needed for replacement • Selection of heifers • Weaning (7-10 mos.) • Cull only those whose wt. is too light to show estrus at 15 mos. • Cull heifers too large in frame & birth wt. • Yearling (12-15 mos.) • Cull those not reaching desired breeding wt. (650-850 lbs.) • After Breeding (19-21 mos.) • Cull open heifers • Cull those calving in latter third of calving season
Selecting Replacement Heifers • After weaning first calf (31-34 mos.) • Cull to actual needed numbers based on weaning wt. performance of first calf • Select for early pregnancy
Cow Selection • Select based upon their performance and the performance of their offspring & additional evidence that they can be productive if bred back • Measured by: • Pregnancy • Weaning/yearling wts • EPD’s of cows
Crossbreeding programs for Commercial producers • Most producers travel w/in 150 mi to select bulls for natural AI • Must have knowledge of who has good genetics • Selection should be based on how each breed complements the other • Why is crossbreeding advantageous for commercial producers?
Crossbreeding programs for Commercial producers • Most heterosis is expressed by weaning time • Two breed rotations • Ex. • Two breed rotation w/ a terminal cross • Ex. • All terminal cross calves are sold • Three breed rotation • Ex.
Figure 25.6 Heterosis resulting from crossbreeding for pounds of calf weaned per cow exposed to breeding. Source: USDA.
Figure 25.7 Two-breed rotation cross. Females sired by breed A are mated to breed B bulls, and heifers sired by breed B are mated to breed A bulls. This will increase the pounds of calf weaned per cow bred by approximately 15%. Source: Colorado State University.
Figure 25.8 Three-breed rotation cross. Females sired by a specific breed are bred to the breed of the next bull in rotation. This will increase the pounds of calf weaned per cow by approximately 20%. Source: Colorado State University.
Figure 25.9 Two-breed rotation and terminal site crossbreeding system. Sires are used in the two-breed rotation primarily to produce replacement heifers. Terminal cross sires are mated to the less productive females. This system will increase the pounds of calf weaned per cow bred by more than 20%. Source: Colorado State University.
Cow-Calf Management • Effective and profitable management of cow/calf operations is dependent upon manager’s ability to budget time to critical activities • Two goals of the operation • Generate profit • Provide opportunities for others • Finishing cattle • Club calves
Cow-Calf Management • Criteria for measuring cow/calf profitability • Calf crop % • Number of calves/cow in breeding herd • Average wt at weaning • Wt at 7-9 mos. • Annual cow cost • Dollars required to keep a cow each yr • See table 26.2 for break-even guidelines
Cow-Calf Management • Costs & Returns • Compute using enterprise budget • Break out each part of the operation in order to evaluate profitability more closely • Typically, increasing weaning % decreases break-even price • Why might this not always be true
Figure 26.2 Annual cow–calf returns and cattle inventory. Source: Livestock Marketing Information Center.
Management for Optimum Calf Crop Percentages • Feed heifers adequately to reach puberty @ 15 mos (650-850 lbs) • Heifers bred to calve early in season • More likely to conceive early as 2 & 3 yr olds • Manage postpartum interval for heifers • Return to breeding time • May feed separately from mature cows • Monitor BCS • Fat/thin cattle have more problems • Observe closely at calving to prevent dystocia (especially heifers)
Management for Optimum Calf Crop Percentages • Manage birth weight • Critical balance between size of calf and dystocia rates • Heavier birth weights usually = heavier calves • Can also lead to problems • Evaluate bulls for soundness, fertility • Bulls can have low libido and/or low sperm counts • cow:bull ratio – 30:1 • Crossbreeding can improve calf crop % by 8-12% • More vigorous calves
Management for Optimum Calf Crop Percentages • Adequate energy intake • Monitor energy intake closely at critical times: • Puberty • Calving • Postpartum period • Balanced diet w/ protein, min/vit • Keep calf losses during gestation low – 2-3% target • Elevated levels often indicate presence of infectious diseases • Keep calf mortality low – 2-3% • Have a plan for severe weather & health challenges • Can reduce calf crop by 10-30% if not done well
Management for Optimum Weaning Weights • Calve early in the season • Each missed cycle during breeding results in 30-40 lb lighter calf @ weaning • Breeders typically limit breeding window to 90d • Keeps calves uniform • Forage/feed availability • Influences calf growth rate • Especially until calf consumes forages on their own @ about 3 mos
Management for Optimum Weaning Weights • Growth stimulants • Increase weaning wts 5-15% • Ralgro, Synovex C, Compudose, etc. • Implanted as pellets under skin • Don’t use on breeding stock • Communicate with buyers for appropriate implant strategy • Can reduce grading and meat quality • Creep feed • Can greatly influence weaning wt • Also adds cost • Best used under drought or marginal feed quality situations