Rafter N Ranch, Inc
EFFECTIVE USE OF ARTIFICIAL INSEMINATION IN BEEF CATTLE
Artificial insemination (A.I.) provides the cow-calf producer an opportunity to use bulls possessing superior genetics. Depending upon the needs and goals of an
individual's breeding program, A.I. offers an economically feasible means of increasing productivity over a wide range of traits. In spite of this enormous potential
to improve production levels, many beef producers have not put themselves in a position to take advantage of the benefits offered by A.I. The missing or limiting ingredient in implementing a successful A.I. program is often management. The use of A.I. necessitates a sound management program. Establishment
of an effective A.I. management program is best approached one step at a time. Factors to be considered are:
1) implementation of an efficient record keeping system;
2) well-designed, strong cattle handling facilities;
3) a sound nutrition program;
4) a sound, effective herd health program;
5) accurate heat detection;
6) a knowledgeable, well trained A.I. technician.
Records
The use of accurate and complete records is an essential ingredient in the implementation of any intensive management system such as A.I.. For an A.I. Program to be
successful, a manager must know both the present reproductive status of each individual cow in the herd and the reproductive history of each cow. Statistics such as calving date, date of first postpartum estrus, actual length of cow's estrus cycle, consistency of estrus cycle length, number of services required per pregnancy, incidence
and severity of dystocia, and individual cow ages are all useful in helping a manager to operate and to pinpoint weaknesses in the system. Only after management deficiencies
have been identified can appropriate solutions be devised and implemented.
Individual cow identification is also a necessary part of a successful record keeping system. There are a number of ear tags on the market which provide an effective,
economical means of individual identification for the cow herd. In purebred herds, it is necessary to also use a permanent form of identification, such as an ear tattoo.
Brands (hot or freeze) are also effective. Table 1 shows some sample record forms. Form A is a sample calving record. Form B records data needed in an A.I. program.
Facilities
A.I. facilities should provide an efficient means of sorting and restraining individual cows. They need not be elaborate or unduly expensive. It is essential, however,
that they be strong and solid. They should be designed and constructed with the idea of minimizing stress and to the cow. Excessive stress and excitement can markedly
reduce conception rates. Although an alley way may be sufficient in which to A.I. cows, a chute and headgate is a wise long-term investment. For practical cattle handling
facilities refer to Beef Housing and Equipment Handbook (MWPS-6), Midwest Plan Service, Iowa State University, Ames, IA 50011.
Nutrition
Nutrition can have a profound effect on the fertility of the cow herd. Nutritional requirements are dependent upon the physiological state of the individual cow.
Lactation, growth, pregnancy, and events surrounding and including parturition exert high demands upon a cow's metabolism. When the level of feed intake is insufficient
to meet the demands of the various physiological states which a cow may be experiencing at any given time, nutrients are diverted towards those functions most essential
to the survival of the cow and her calf. When this happens, the cow's ability to cycle regularly, and to conceive and maintain a pregnancy is often impaired.
Particularly critical times in most beef cow operations are the last 60 days prior to calving and the first 60 days following calving. Research has shown that during
the late prepartum period, cows receiving an insufficient level of energy to maintain their body condition experience a prolonged postpartum anestrus period. Because
of the demands exerted by the initiation of lactation, the postpartum period is also critical.
Feed requirements of cows in different physiological states and cows with different production potentials can vary greatly. It is therefore advantageous to separate
and feed cows based upon their age, lactational status, pregnancy status, and production potential. This can help eliminate the economic losses produced by both underfeeding
and overfeeding of cows.
Classes of nutrients that are important are energy, protein, vitamins and minerals. While adequate energy intake can be effectively estimated by monitoring changes in
body condition, deficiencies in other nutrients are more difficult to detect.
In general, protein deficiencies are rare in beef cows. Dry cows require approximately 8% crude protein; lactating cows about 12%.
Cows on green growing forages rarely experience vitamin deficiencies. However, several vitamins become inactive under prolonged storage conditions and in some ensiling
processes. Specifically, vitamins A, D and E are important in maintaining the integrity the reproduction tract, synthesis of steroids and normal cyclicity. Therefore, injections of vitamins A, D and e prior to parturition may be beneficial for cows wintered on poor quality forage.
Several minerals can be deficient in the brood cows diet. Calcium and phosphorus are two minerals which are essential for both milk production and reproduction. Another
mineral of particular importance is selenium (Se). Se supplementation has resulted in significant increases in overall fertility in certain areas of the nation. Additionally, Se has been implicated in the immune system. Table 3 presents a free-choice mineral mix which provides adequate levels of minerals and vitamins.
Herd Health
Reproductive performance and the ultimate success of an A.I. program can be greatly affected by the health status of the cow herd. Table 4 lists the important diseases that affect reproductive performance and the vaccination schedules which are most effective against them. Michigan law requires that all replacement females be calf hood
vaccinated for brucellosis (Bangs) between the ages of 4 and 8 months of age by a licensed veterinarian. Bangs vaccination laws vary from state to state.
The other vaccinations should be administered under the advise of a veterinarian. Certain modified live virus vaccines should not be used on pregnant cows because of risk of abortion. Based upon a producers herd history and area, a veterinarian
can establish a safe and effective vaccination and overall herd health program.
Heat Detection
Figure 2 outlines the timing of events surrounding estrous. Conception is dependent upon proper timing of insemination with ovulation. Insemination 10-14 hours following standing heat is the best way of ensuring this. Accurately identifying the period of standing estrus or heat is often the most difficult and limiting aspect of an A.I.
program. Heat detection is difficult for two reasons. First of all, it requires a serious commitment of time. Good heat detection involves careful observation of the cow
herd at several times during the day. Each period of observation should last for a minimum of 15-20 minutes. Furthermore, a successful estrus detection program involves
3-4 observation periods per day.
The second requirement of accurate estrus detection is a practical understanding of the cow's behavioral responses and physical reactions around and including estrus.
Signs that indicate a cow is approaching estrus include:
1) increased activity, nervousness, and restlessness,2) riding or mounting of herd mates,3) swelling and moistness of the vulva,4) presence of a clear mucous discharge on the tail, vulva, and/or rump,5) and finally, standing to be mounted by herd mates.
Generally speaking, standing to be mounted is the best sign of estrus to use for scheduling insemination. Insemination 12 hours following standing heat will result
in maximum conception rate. Using the signs of approaching estrus usually results in insemination too far ahead of ovulation to allow for sperm to survive.
A.I. Technician
The final ingredient in a successful A.I. program is a properly trained and knowledgeable A.I. technician. Effective training sessions are conducted by most A.I. organizations. Two important areas which require the most proficiency are semen handling and proper placement of the semen in the females reproductive tract.
Extreme caution must be exercised when handling semen. The first procedure which requires care is the thawing process. Semen is stored in liquid nitrogen
(approximately -240oF.). Any rise in temperature prior to thawing can kill sperm cells. This can present obvious problems in cold weather. Careful adherence to
thawing instructions and insemination techniques will minimize these hazards. Secondly, water is lethal to sperm. Careful drying of the semen straws and cleaning of the equipment will minimize this problem. The use of new clean dry paper towels is important.
Palpation of the reproductive tract and good A.I. technique are skills which require practice and repetition in order to become proficient. Research shows that even
experienced A.I. technicians have difficulty depositing semen at the desired location within the uterine body. Using radiography, inseminating syringe tip placement
and inseminate distribution was measured for 40 A.I. technicians. Results of this trial and others indicate that approximately 20% of all A.I. attempts result in semen
deposition in the cervix. Other studies show that cervical deposition of semen during A.I. results in near-zero conception rates. More recent studies show that A.I.
technicians can be trained so that over 90% of inseminations will result in uterine body or uterine horn deposition (McKenna, et.al., 1989).
While A.I. provides many advantages to beef producers for genetic improvement, it requires improved management techniques that parallel the potential improvements. Although not a "free-lunch", A.I. can provide significant return on investment when implemented within careful planned and conducted management programs.
Table 1. Cow Herd Record Forms
Form A -- Calving Record (USE THE FOLLOWING AS COLUMN TITLES) Calf I.D. Cow I.D. Calf Sire Calf Birth Weight Birth Date Calving Ease Score Comments
Form B -- A.I. Record (USE THE FOLLOWING AS COLUMN TITLES) Cow I.D. Calving Date 1st P.P. Estrus A.I. Sire 1st Serve. Date 2nd Serve. Date 3rd Serve. Date 4th Serve. Date
Table 2. Sorting Schemes For Feeding The Beef Cow Herd:
(THE FOLLOWING TABLE DOES NOT TRANSLATE ON THE COMPUTER, PLEASE SEE BULLETIN E-1636 FOR A COPY OF THE RECORD) By Physiological Status Sorting Scheme Greatest Feed Requirements Least Feed Requirements 1 Preg. Yrlng. Heifers Preg. 2-3 Yr. Old Cows Preg. Cows >3 Yr. Old Cows Open Females 2 Preg. Femeles < 3 Yrs. Old Preg. Females > 3 Yrs. Old Open Females 3 All Preg. Females and All Females with B.C. <5 Remaining Open Females 4 Thin Females (B.C. <5) Fat Females (B.C. >5) 5 Lactating Females Nonlactating Females
Table 3. Beef Cow Herd Free-Choice Mineral- Vitamin Mix
Ingredients Concentration Salt (NaCl) 28.15% Calcium 8.27% Phosphorus 8.27% Magnesium 11.60% Manganese .33% Zinc .67% Iron .41% Copper .17% Selenium .006% Iodine .022% Cobalt .008% Vit. A (I.U.lb) 298,051 Vit. D (I.U. lb) 30,985 Vit. E (I.U. lb) 1,134 Soy or coconut oil 1.25% Natural dry licorice 0.10% Approximate daily consumption rate = .15 lb/hd/day
Table 4. Immunization Program.
Disease Timing Number of Doses Interval Between Doses Interval Between BoostersBrucellosis 4-8 mo. (Mich.) 1 None None IBR Pre-weaning 2 2-3 weeks annually 1 dose BVD Pre-weaning 2 2-3 weeks annually 1 dose Leptospirosis (5-strain) Pre-breeding 2 2-3 weeks 6-12 mo. 1 dose Clostridium (7 strains) Pre-weaning 2 2-3 weeks annually (OPTIONAL) BRSV Pre-weaning 2 2-3 weeks annually 1 dose Haemophilus Pre-weaning 2 2-3 weeks annually 1 dose Campylobacter (vibriosis) Pre-breeding 2 2-3 weeks annually 1 dose Rota/Corona & E. coli Pre-calving 2 2-3 weeks annually 1 dose
