Managing an AI program
Artificial insemination (AI) programs can vary greatly in their cost and level of success. To maximise results and benefits, it is extremely important that AI programs are planned in advance and managed well.
What role can AI have? Why use AI?
- Artificial insemination is a tool that allows access to sires of high ‘genetic merit’ that are not readily available or too expensive to purchase
- Artificial insemination also allows a sire to be used over large numbers of females compared to natural service
- Fixed time artificial insemination (FTAI) is a tool that allows large numbers of Brahman and Brahman-infused females to be inseminated in a six hour window
- Artificial insemination is a very useful tool to disseminate ‘superior genetics’ efficiently and expediently into large tropically adapted, northern Australian beef herds.
Female selection for AI programs
Many AI programs involve the use of maiden heifers, as they are under much less stress than lactating cows and often provide higher submission rates. Mature cows are better to use than lactating first calf heifers as this latter class is under more stress. Wet cows should not be included in an AI program until 60 or more days after calving. Even after this time, a number of cows will not have returned to their normal oestrus cycle.
- Two-year-old Brahman and Brahman-infused heifers should have a mating target weight of 320–350kg
- Wet cows should have a minimum forward store body condition
- All females should be non-pregnant and cycling
- All females for an AI program need to be individually identified. A large flag eartag linked to the NLIS tag number is useful.
Knowledge of fertility status of the herd is useful. Do heifers have a regular high and early conception pattern? Are the cows regular calvers?
- Good nutrition is essential for at least six weeks before and after an AI program
- Planning and management of the nutrition of AI heifers should start at weaning to ensure adequate growth to meet the target mating weight
- Nutritional management of cows should start well before calving to ensure the target body condition and bodyweight are achieved by the time of AI.
- Vaccination against infectious diseases that affect pregnancy and calving rates must be implemented
- Important diseases include bovine pestivirus, vibriosis, bovine ephemeral fever (three day sickness), and leptospirosis
- Vaccination should be carried out at least eight weeks prior to mating. Leptospirosis vaccination (as it is a disease of late pregnancy) should be given mid-pregnancy.
Buffalo fly infestation can be a major problem at time of AI. Control of fly numbers can reduce the stress level on both cattle and operators during heat detection and processing operations.
Selection of sires for AI
- Have the sires you are considering for AI got genetic progress or improvement to offer you?
- Do the sires to be used have measured genetic differences in traits economic to your herd?
- Will they improve and maintain the fertility genetics of your herd through their progeny?
- What about structural soundness, growth, carcase and temperament?
- Do these sires have above average and balance in their traits, that is, above average EBVs?
Selection of mop-up sires
Ensure mop-up and herd sires have:
- Been through a Bull breeding soundness evaluation (BBSE) (includes structural and reproductive organ (scrotum, penis and internal reproductive tract evaluation), soundness evaluation and a minimum of 70% normal sperm at two year old)
- Vaccination against main diseases
- Above average EBVs for reproductive, growth and carcase traits (see BREEDPLAN EBVs)
- Sound temperament (see Improving temperament and flight time).
Ensure semen to be used for AI passes the minimum standards.
Order in advance
- Organise semen, equipment and drugs six weeks in advance.
Number of females per sire used in AI
This applies to BREEDPLAN herds. For accuracy of data, inseminate at least 30 to 40 females per AI sire to produce at least 12 to 20 progeny per sire.
Types of AI programs
- Without synchronisation, a program will run for 23 days for one oestrus cycle with heat detection and insemination twice per day (morning and evening)
- A range of oestrus synchronisation programs are available to reduce time and labour spent on a program.
Synchronisation of oestrus saves time and labour. There are three basic types of synchronisation:
- prostaglandins – a hormone administered as an injection that shortens the reproductive cycle. It will work only on cattle that are already actively cycling. The most usual is a 10 day program with heat detection and insemination twice a day.
- progesterone implants – a removable implant placed inside the vagina or under the skin behind the ear, which postpones the onset of oestrus until two days after removal. The implants are usually left in for 8–11 days. Five-day AI programs are possible here with heat detection and insemination twice a day.
- fixed time insemination – a removable vaginal progesterone implant in conjunction with a series of hormone injections will align oestrus so that a group of cattle can be inseminated in a six hour period without heat detection. This type of program is appropriate for large numbers and in particular cows with calves at foot.
The accurate detection of standing heat and the resulting timing of insemination are critical to an AI program’s success (a non-FTAI program). Clear identification of individual animals, record keeping, visual observations for signs of heat and, where necessary, the use of heat detection aids are all critical factors in an AI program.
Animals detected on heat in the morning are inseminated in the evening and animals detected on heat in the evening are inseminated next morning.
On heat in morning – Inseminate that afternoon
On heat in evening – Inseminate next morning
Cattle handling during AI programs
- Cattle handling has an effect on the behaviour of the cattle and how they work through the yards, race and veterinary crush
- Calm, steady handling using common sense will encourage the steady flow of cattle.
- A covered veterinary crush is essential to provide shade for protection for the semen and more comfortable conditions for both cows and operators
- Concrete floors and aprons will help overall hygiene, cleaning and general operations
- If large scale AI is to be conducted on a regular basis, a small shed or room near the crush will increase the efficiency of the program
- Clean water at the site will enhance working conditions and hygiene.
Large scale programs
In large scale programs, 200 head may be inseminated in a six hour window.
- Skilled and experienced inseminators are needed for this sort of program
- Skilled staff are required for the head bail/slide gate and backyard to manage the steady flow of cattle.
Semen handling and insemination technique
Semen is a live biological product and must be handled correctly. It is susceptible to temperature shock, and exposure to sunlight, water, blood and poor hygiene. The recto/vaginal insemination technique gives the best results.
To inseminate the cow or heifer, slowly deposit the semen, two-thirds in body of uterus, one-third in mid-cervix, withdraw the AI gun and massage the cervix.
|SEMEN HANDLING AND INSEMINATION GUIDE
|Work in the shade as: sunlight kills spear, cows are quieter, everyone is more comfortable.
|Have cow in the vet crush before handling semen.
|Thawing: Keep water level just below tip of crimped end, temperature of water at 35°C,
extra supply of hot water to maintain at 35°C.
|Kit box: Ensure gun is accessible but protected, ensure sheath is accessible but protected,
ensure scissors are clean.
|Locate semen in the unit using records.
|HYGIENE AND SAFETY
|Keep hands clean and dry.
|Use tweezers when removing semen from the unit.
|Do not over-expose semen.
|Keep straws as low in the neck of the unit as is comfortable.
|Do not handle the tapered end of the sheath.
|Handle straw by the ends only.
|Dry the straw thoroughly without excess rubbing.
|Check ID of the bull.
|Roll the double plug end and place the straw in the gun (crimped end is always up).
|Pre-warm the gun if necessary.
|Cut the crimped end off in the air space and reclean scissors.
|Cover gun with sheath.
|Bring the semen to tip of sheath and straw so that there is no hollow space for contamination transfer.
|Avoid gun contact with anything.
|Hygiene: Wipe vulva. Open vulva.
|Inseminate cow: Slowly deposit the semen – two-thirds in body of uterus, one-third in mid-cervix. Withdraw gun and massage the cervix.
|Unload gun Check tip of gun for blood. Recheck bull ID. Dispose of straw thoughtfully.
|Fill in records.
|THERE ARE NO SHORT CUTS!
You have accessed good quality semen from bulls with quality genetic performance information and inseminated a number of females. Good records are essential to maximise the results of your program.
- All females should be individually identified
- Keep records on all AI details
- Keep records on pregnancy results to AI
- Mother-up cow and calf
- Keep track of the performance of progeny of each bull
- Fill in the records.
Variation in gestation length
Your AI program may have resulted in producing a lot of pregnant females on the one day. Be prepared that females that fall pregnant on the one day can calve over a four to eight week period, that is, from two to four weeks each side of the average. This is normal.
- Ensure good paddocks and feed six weeks BEFORE and AFTER program.
- Organise semen and equipment six weeks BEFORE required.
- Only use cows KNOWN to be empty and cycling in program.
IDENTIFY BEST TIME TO INSEMINATE
Greg Fawcett (Beef Breeding Services) and Alan Laing (formerly, Queensland Government).