Total Number of Breeding Beef Cows

Beef Breeding Season Management

Table of Contents

1. Introduction
   • Reproductive Charge per unit
2. Why Cows Exercise Not Become Pregnant
   • Fourth dimension of Calving
   • Body Status
   • Suckling
   • Weight Changes
   • Body Condition Scoring
   • The Bull
   • Bull to Cow Ratio
3. Case Breeding Program (Tom O'Connor)
4. Length of Breeding Season
5. Advantages of a Shortened Convenance Flavor
6. Breeding Replacement Heifers
7. Artificial Insemination (AI)
   • Heat Detection
   • Heat Detection Aids
   • Insemination Methods
   • Estrus Synchronization
   • Pregnancy Examination
8. Monitoring Reproductive Efficiency
   • Summary for Improved Reproductive Efficiency
9. References

 Introduction

In analyzing the cow-calf industry, the four factors that are more commonly used by producers as influencing profit are:

1. weaning weight of the calves
2. percentage of cows weaning calves
3. annual toll of maintaining the moo-cow
4. the price received for the calves

In evaluating research on cow efficiency, it is apparent that one of the more important factors influencing the overall productivity and efficiency of the beefiness cow herd is reproductive efficiency.

Reproductive Charge per unit

Table 1. Miles City Study (Montana 14 twelvemonth).

No. of cows	Non-Pregnant at terminate of breeding flavour	Calves lost during Gestation	Lost Near Birth	Lost Birth to two weeks	Calf Crop Weaned
12,827	17.4%	2.3%	vi.4%	two.nine%	71.0%

If the percent calf crop is to be improved, the number of cows becoming pregnant must be increased and the losses near or shortly, after nativity decreased.

Why Cows Do Not Become Significant

Much research has been washed indicating that many cows neglect to show heat early on in the breeding flavor and besides that formulation rate at starting time service is low. If, however, proper management procedures are utilized the number of cows showing oestrus the starting time 21 days of convenance every bit well equally the conception rate at start service can be high.

Factors affecting the number of cows showing rut early on in the breeding flavour and the number conceiving on first service are:

• Showing Heat Kickoff 21 Days of Breeding
  1. Fourth dimension of Calving
  2. Trunk status of cows at calving time
  3. Age of the cow
  4. Suckling
• Conception Rate at Kickoff Service
  1. Time of Calving
  2. Weight changes of moo-cow nearly breeding fourth dimension
  3. Bull fertility
  4. Balderdash to cow ratio

Time of Calving

Cows calving late in the calving season mostly have a lower pregnancy rate because they exercise not have time to bear witness estrus early on in the breeding season.

Cows require acceptable diet and balance post calving in social club to cycle normally. Formulation rate is higher in cows bred 60 days or more afterward calving.

Body Condition

Body condition is important in determining when a cow shows estrus following calving. Ninety-one percent of the cows in skillful body status at calving had shown heat by 60 days post-calving, as compared with 61 % of the cows in moderate condition and 46% of the cows in thin torso condition.

Table 2. Trunk Condition at Calving and Estrus after Calving

		Days after Calving (%)
Trunk Condition at Calving	No. of Cows	40	50	60	lxx	80	90	100	120
Sparse	272	19	34	46	55	62	66	seventy	77
Moderate	364	21	45	61	79	88	92	100	100
Proficient	fifty	31	42	91	96	98	100	100	100

Ref: Wiltbank

Suckling

Cows that are suckled accept longer intervals from calving to first estrus. Flushing and 48-hour calf removal can be helpful in improving reproductive performance. Neither practise solitary is equally beneficial as a combination of the two.

Removing calves for 48 hours can be a problem in some situations. The best fashion to accomplish this is to combine calf removal with working the calves. Calves must not nurse for 48 hours to get maximum results.

Weight Changes

Weight changes near convenance time bear upon pregnancy rate. Sixty-seven percentage of the cows that held their weight from calving to breeding conceived on starting time service every bit compared with 43% in cows losing weight during this menstruum. The pregnancy rate after 21 and xc days of breeding was also higher in cows holding their weight as compared with cows losing weight.

Body Condition Scoring

As has been discussed, body condition of the moo-cow at calving (moderate or good) and post calving to breeding volition have a direct bearing on improved convenance efficiency.

Virtually scoring systems have been based on palpation of the back and hindquarters of the moo-cow. Detail attention is given to the chine, loin. rump, tail head. hook bone and pin os regions. Cows in i system are scored on a scale of one to 5. A score of one indicates severe nether conditioning while a score of 5 is assigned to over conditioned obese cows.

Scoring System

• Score 1. Private spinous processes accept limited mankind embrace; the ends are precipitous to bear on; they requite a definite overhanging shelf outcome to the loin region.
• Score 2. Transverse processes tin can be felt, only not prominent; rounded with some fat cover.
• Score 3. Transverse processes can be felt with firm pressure; processes appear polish; the overhanging shelf effect is not noticeable.
• Score 4. Individual processes only felt with very firm pressure level; rounded with no overhanging shelf effect; loin and rump appear flat; tail head and pins are rounded.
• Score v. The structure of the transverse processes, hook and pivot bone region is non apparent; fat deposition is obvious and prominent.

Ref: E.E. Wildman

Figure 1 . Trunk Condition Scores vs. Calving Interval (days).

The relationship noted above has led to the recommendation of a Mating Target Score of ii½.

It may non be necessary or applied to palpate all cows under most circumstances but an understanding of the scoring system and what is involved would allow eye-balling or visual appraisement of cows to evaluate status.

Cows should be in moderate to practiced body condition at calving fourth dimension to attain optimum reproductive performance.

Possible Scoring Use

1. Detect cows one or two months before calves are scheduled to be weaned. If cows are thin, supplement feed or wean calves.
2. Sort cows by trunk status at weaning fourth dimension - feed appropriately.
3. Prior to calving.
4. Middle of calving season (prior to breeding)

Suitable adjustments must exist made to the feeding plan to see the target score if cows are indeed too thin.

The Bull

Status and nutrition of the bull prior to convenance are equally important to breeding efficiency.

Unfortunately very few bulls undergo any thorough breeding soundness examinations prior to the breeding season.

A breeding soundness examination would involve:

1. Conformation
2. Concrete Examination
   • scrotum and testicles
   • scrotal circumference
   • penis and prepuce
3. Semen Evaluation
   • book
   • concentration
   • mortality and morphology

Scrotal Circumference

Research has documented that testicular and scrotal development is direct related to sperm production and fertility in bulls. Scrotal circumference measurement properly washed provides an aid in selecting sires with normal testicular development and is of considerable importance, particularly in yearling bulls.

Factors Affecting Bull Reproductive Potential

1. Testicular and scrotal development.
2. Ability to physically breed females.
3. Semen quality and volume.
4. Libido or serving chapters.

All four are of equal importance and testing would be a recommended procedure where practical earlier a bull is used.

Table 3. Scrotal Circumference in Centimetres.*

	Age (months)
Classification	12-14	xiv-20	21-30	30+
Very Practiced	>35	>37	>39	>40
Poor	<xxx	<31	<32	<33

*The average scrotal circumference will vary according to breed.

Bull to Cow Ratio

Table 4. Number of Cows per Bull.

Bull Historic period	Mating System
	Pasture Mating	Hand Mating
Yearling	10-20	twenty-xxx
ii year old	20-30	30-twoscore
3 year olds & older	30-40	40-sixty

These figures vary considerably with the condition of the pasture, the sex drive of the bull, the fertility level of the cow herd and the length of the breeding season.

Example Breeding Program (Tom O'Connor)

The O'Connor programme involves five factors:

1. Threescore-day convenance.
2. Cows in moderate or good condition at calving fourth dimension.
3. Cows proceeds in weight for iii weeks before the start of breeding season and during convenance flavor.
4. Calves removed from cows for 48 hours at starting time of breeding season.*
5. Cows bred to fertile bulls.

* This factor may not exist practical to the majority of commercial producers.

80 percent of the cows were pregnant afterward 30 days of breeding in the O'Connor herd that utilized these v factors. After 42 days of breeding, 87% were pregnant.

Length of Convenance Flavor

The length of the breeding flavor is an important cistron in determining pregnancy rate. It has been shown that late-calving cows take smaller calf crops than do early calving cows. The only reliable method for making sure cows calve early on in the calving season is to have a curt convenance flavour.

A 60-90 24-hour interval breeding season should be a goal of almost moo-cow-dogie producers with 45 to threescore days being more desirable. This could be accomplished by gradually reducing the breeding season each year by 2-iii weeks which would event in fewer open cows beingness culled within a given year. Acceptable nutrition and management are essential to success.

Table 5. Effect of Shortening the Calving Flavor.

Year	No. of Cows	No. of Heifers	Length of Breeding Season (Mo)	Calving in Desired Time (%)*	Calf Ingather	Weaning Weight		Pounds of Calf Per Moo-cow Exposed
						Actual	At 205 Days
1st	74	0	11	38	69	400	400	272
2nd	63	iii	7	62	85	428	432	295
3rd	52	17	iii	89	86	476	452	405
fourth	58	23	2	100	83	509	459	499

*Of cows calved. Ref: Spitzer

Advantages of a Shortened Breeding Season

1. More concentrated management (time and labor).
2. More uniform group of calves by age, size and weight to sell at weaning.
3. More than uniform group of calves past age, size and weight to feed as a management grouping if calves are kept and fed.
4. Early calving cows usually wean heavier calves.
5. Nutrient requirements of the moo-cow herd will be much easier to meet during the critical stages of the product cycle with all cows calving within a shorter flow.
6. Eliminate cattle with depression fertility from the breeding herd.

With shorter breeding seasons success will be dependent on feeding and breeding management. Acceptable diet and rest are essentials to fertile and cycling cows. Equally important is the health, condition and fertility of the balderdash if natural service is used. During the breeding season it is of import that the herd exist checked routinely to observe convenance progress.

Convenance Replacement Heifers

When considering a shortened convenance season, heifer management at breeding will be of importance. Yearling replacement heifers should exist bred 3 weeks prior to the breeding of the mature cow herd. Heifers will crave a longer catamenia of time to begin cycling and show oestrus subsequently calving than mature females. Heifers bred before the chief moo-cow herd, will calve earlier in the season and will be cycling normally by the time the main moo-cow herd is being bred the following yr. If nosotros want a heifer to exist a good lifetime producer she must calve early. She must prove estrus and conceive early on in the breeding season. Heifers calving tardily ordinarily become late calving cows.

The lifetime production of beefiness females can exist increased by calving at two years of historic period. This can exist achieved by producers willing to provide the required nutrition and direction.

Tabular array 6. Reproductive Performance in Hereford Heifers equally Influenced by Weight at Beginning of Breeding (Tom O'Connor).

	Under 550 lbs	551-600 lbs	Over 600 lbs
No. Heifers	40	166	45
Pregnant 60 days (%)	65	77	xc
Calves weaned (%)	40	71	86
Losses pregnancy test - weaning (%)	25	vi	4
Wet cows pregnant - 2d year (%)	18	57	69

Artificial Insemination (AI)

Those because or using AI should ensure that the breeding season does not go lengthened in attempts to settle cows. Pinnacle breeding management is required for successful oestrus detection and high conception rates with AI.

A suggested practice would be to breed the top finish of the herd AI the first 25-thirty days of the breeding season and employ a clean-up bull or bulls for the remainder of the breeding period.

A audio health program and good nutrition are requirements of any breeding plan. They become fifty-fifty more important in an AI program.

Proper handling facilities are essential to an AI program. They can be very simple or elaborate. Anything that can be done to reduce handling stress volition profoundly increase conception rates.

Success with artificial insemination requires summit direction. Management must exist willing to provide the additional labor which will always be above the requirements for natural mating.

Heat Detection

Individual cow identification visible from a distance and adequate records are essential components of a successful oestrus detection program.

Table 7. Heat Detection.

Number of Ascertainment Periods	% Cows seen in Rut
Once a day	threescore
Twice a twenty-four hours	80
Three times a mean solar day	90
Four times a twenty-four hours	100

A higher detection charge per unit of cows in heat has been observed earlier apex than during the afternoon and evening. Shortly subsequently sunrise a special endeavour should exist made to detect rut.

Oestrus Detection Aids

1. Kamar Patch - pressure level sensitive devices glued to the rump of cows for rut detection.
2. Sterilized Bulls - surgically contradistinct bulls.
3. Teaser Bulls
4. Hopped up Heifers - heifers treated with hormones.
5. Mentum Ball Marker - detector animal fitted with this mark.

Insemination Methods

Cleanliness during all insemination procedures is essential and is a disquisitional point for success or failure.

Estrus Synchronization

Injection of a natural or synthetic prostaglandin will induce heat in sexually mature and cycling females. Cattle which are not reproductively cycling must non be included in an estrus synchronizing program.

Rut synchronization with prostaglandins has the potential to amend and increase artificial insemination (AI) programs with cattle.

Controlled breeding programs will reduce time and labor involved with heat detection and shorten both the breeding season and calving flavour. Total Cost factors would have to be considered.

With good management this program tin be successful.

Pregnancy Examination

Pregnancy examination as a routine practice at the end of the breeding season can be an important tool in improving the efficiency inside the beef cow herd. Identifying open cows which can be effectively marketed will reduce wintering costs and increase efficiency of production.

Pregnancy examination should accept place 6 to viii weeks after the end of convenance season.

Advantages of early pregnancy diagnosis in beefiness cattle are:

1. Gives alarm of breeding issues (infertility and problem breeders)
2. Improved fertility - effective alternative and marketing of problem breeders.
3. Reduced overhead costs - constructive use of time, labor, facilities, etc.
4. Guarantee pregnancy in females for sale.

Monitoring Reproductive Efficiency

Records are essential to identify where losses occur in the reproductive cycle. This summary (Table 8) volition permit calculation of reproductive performance indices that volition enable you lot and your veterinary to make breeding management decisions.

Records are essential to identify where losses occur in the reproductive cycle. The following summary will permit adding of reproductive performance indices that will enable you and your veterinarian to make breeding management decisions.

Table 8. Monitoring Reproductive Efficiency.

	Heifers	Cows
Convenance History
Number exposed to natural service
Date bulls turned out
Appointment bulls removed
Number of bulls used in ii & 3
Number exposed to bogus service
Date first AI service
Date concluding AI service
Full number of AI services
Number significant past natural service
Number pregnant by artificial service
Appointment of pregnancy check
Breeding to Calving Period (died = culled)
Number of open up cows culled
Number of open cows sold
Number of pregnant cows culled
Number of pregnant cows sold
Number of abortions
Number due to calve
Calving History
Number of liveborn calves
Number of stillbirths
Date first calving
Engagement of last calving
Number barren

Summary for Improved Reproductive Efficiency

1. Body condition score
2. Diet - bulls and cows
3. Breeding soundness examinations
4. Balderdash to cow ratio
5. Breed heifers - target age 14-15 months - 3 weeks before cows.
6. Convenance season 45-60 days
7. Calving season 45-sixty days
8. Pregnancy Exam
9. Cull open or barren cows
10. Monitor performance.

A highly managed cow herd volition be much more than efficient and productive. Discuss your reproductive program with your local veterinarian, and/or AI company.

References

1. Beefiness Moo-cow Efficiency Forum '84 L. Corah
2. Cattlemen'south Library
3. Veterinary Clinics of Due north America. J.Northward. Wiltbank

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Source: http://www.omafra.gov.on.ca/english/livestock/beef/facts/85-054.htm

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