Reproduction on the Ranch

Clay Lents1, Kraig Peel2, George Seidel Jr.1,and Gordon Niswender1

Colorado State University

1Animal Reproduction and Biotechnology Laboratory2Western Center for Integrated Resource Management

Clay Lents1, Kraig Peel2, George Seidel Jr.1,and Gordon Niswender1

Colorado State University

1Animal Reproduction and Biotechnology Laboratory2Western Center for Integrated Resource Management

Reproduction on the RanchReproduction on the Ranch

Reproduction on the Ranch

• Reproduction is the most important trait

• Heifer Development and Management

• Reproduction in Mature Cows

• Management of Bulls

• The Future

Example

If we increase calf crop by 5%

300 Cows would yield 15 additional calves

15 calves average 450 pounds at weaning and sold at $.90 would equal $6075 additional income

OR

Cull the 15 open cows

15 cows off the ranch which cost $300/year= $4500 annual savings

Sale of 15 cows at $400=$6000

$10,500/year

Receipts from cull cows only pay for at best, 60% of the cost of replacements

Reproduction on the Ranch

• In General:– Reproductive traits have low heritability

– But, reproductive traits do respond well to changes in management and environment

Heifer Management

• Heifers should conceive by 14 months of age

• Heifers should be in a BCS of 6.5 at calving (genetics, nutrition, environment)

• Strategies to increase pregnancy rates for first calf heifers– Provide extra feed– Match heifers to their environment– Remove calves for 48 hours or early wean

calves (6-8 weeks)

Typical Natural Service Cost Per Calf (ABS)

Bull Purchase Price

$ 1,800 $ 2,000 $ 2,500 $ 3,000

20 cows/year for 3 years

$ 54.60 $ 59.30 $ 71.05 $ 82.81

25 cows/year for 3 years

$ 43.68 $ 47.44 $ 56.84 $ 66.25

30 cows/year for 3 years

$ 36.40 $ 39.53 $ 47.34 $ 55.20

*Typical natural service costs assume $800 salvage value, $500 annual feed & veterinarian, 95% final conception rate, 10% risk and 8% interest rate.

$ 47.44

AI Cost Analysis with Varying Estrus Response and Pregnancy Rates (ABS)

Est

rus

Res

pons

e R

ate

Pregnancy Rate of those Responding

60% 70% 80% 90% 100%

70% % AI PregCost/Synch AI Preg

42%

$64.29

49%

$55.10

56%

$48.21

63%

$42.86

70%

$38.57

80% % AI PregCost/Synch AI Preg

48%

$60.42

56%

$51.79

64%

$45.31

72%

$40.28

80%

$36.25

90% % AI PregCost/Synch AI Preg

54%

$57.41

63%

$49.21

72%

$43.06

81%

$38.27

90%

$34.44

AI Cost Analysis with Varying Estrus Response and Pregnancy Rates (ABS)

Est

rus

Res

pons

e R

ate

Pregnancy Rate of those Responding

60% 70% 80% 90% 100%

70% % AI PregCost/Synch AI Preg

42%

$64.29

49%

$55.10

56%

$48.21

63%

$42.86

70%

$38.57

80% % AI PregCost/Synch AI Preg

48%

$60.42

56%

$51.79

64%

$45.31

72%

$40.28

80%

$36.25

90% % AI PregCost/Synch AI Preg

54%

$57.41

63%

$49.21

72%

$43.06

81%

$38.27

90%

$34.44

Reproduction on the Ranch

• Average Cost of Natural Service per Calf– $2000 bull/25 cows per year/3 years

• $47.44

• Average Cost of Estrus Synchronization and AI– 90% in estrus, 70% pregnancy rate

• $49.21

Reproduction in Mature Cows• Genetics are important (Seedstock)

• Genetics are important (Commercial)

• Match time of calving and peak lactation to available forage

• Body condition score influences post partum anestrus

Reproduction in Mature CowsTrait Total heterosis, %

Cow milk production 9 Calf wn. wt./cow exposeda 18 Cow forage intake 2 Cow efficiency 2 Cow-calf TDN consumed 3 Calf wn. wt./cow wt. 8 Cow longevity 38 Cow lifetime productivity 25 Adapted from Kress, Don D. and M. D. MacNeil. 1999

Reproduction on the Ranch

2

3

4

5

6

7

D J F M A M J J A S O N D0

0.5

1

1.5

2

2.5BC SMP

Month

BC

SM

P, available lbs/d

1200 lb cow producing 20 lb of milk requires 2 lb of MP inearly lactation

Calving Breeding

**** **

Breeding Soundness Exam

• Structural soundness, scrotal circumference, semen quality

• Pregnancy rates increase 6-10%

• More cows pregnant at first service

• Increase bull to cow ratios (1:40 or higher)

• Every $1 invested yields $17

(Chenoweth 2000)

The FutureThe Future

• Cloning will not be routine in near future

• Synchronized ovulation – timed insemination

• Use of sexed semen

• Cloning will not be routine in near future

• Synchronized ovulation – timed insemination

• Use of sexed semen

Heifers producing Heifers

• More rapid genetic improvement

• Heifer calves weigh approximately 6 pounds less at birth

• Match cows to environment – use terminal sires

Summary• Before using any procedure to modify reproductive

performance, be certain that use of the procedure will advance your goals and fit with available resources.

• A well designed crossbreeding program results in increased conception rates, calf survival, weaning weight, reproductive performance and longevity, which result in increased lifetime productivity and profits.

Summary

• In general, beef heifers should be bred before the cow herd to maximize their chances of rebreeding as first-calf heifers and remaining in the herd.

• The calving/breeding season should be limited and, in most cases, matched to the available forage.

Summary

• In special cases, treatments for synchronization of estrus can induce puberty and/or post-partum estrous cycles and enhance reproductive performance.

• Breeding Soundness Exams for bulls are a key strategy to increase reproductive performance and reduce costs in nearly all cow herds.

Returns on Tested Angus Bulls (ABS)

Data from central bull test

Test A Test B Test C Test D Totals

# Bulls

All angus435 325 136 210 1106

% A.I. Sired

77% 71% 38% 81% 71%

% non A.I. Sired

23% 29% 62% 19% 29%

Avg. $$ A.I. Sired

$2,073.73 $1,661.85 $1,763.46 $1,591.81 $1,828.46

Avg. $$ Non A.I. Sired

$1,733.50 $1,540.26 $1,748.81 $1,491.67 $1,650.16

A.I. Premium

$340.23 $121.58 $14.65 $100.15 $178.30

Reproduction in Mature Cows

Reproduction in Mature Cows

Effect of Mating System

01020304050607080

R RT T

Mating System

Ne

t R

etu

rn (

$/C

ow

)

(R=3-breed rotation, RT=2-breed rotational terminal sire, and T=static

terminal sire)

Reproduction on the Ranch

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9

Body condition score at calving

Inte

rval

fro

m c

alvi

ng

to

est

rus,

d

Low nutrition

Adequate nutrition

High nutrition

Relative Economic Value

02468

101214161820

Repro Production Product

Wilham

Melton

Average