AI in Cattle

18th June 2019

What’s Involved & What are the Benefits??

Artificial insemination (AI) is becoming a more widespread tool within the beef industry in Australia. Once seen as being limited to use within the stud industry, it has rapidly gained in popularity amongst commercial beef producers in the past decade or so.

There are a number of benefits gained by using AI programs within your herd including the following:

  • Access to superior genetics – In the past few years bull prices have jumped considerably. This has greatly reduced access to advanced genetics. AI allows greater opportunity to obtain progeny from top bulls through purchasing semen ($20-50/straw) rather than having to purchase the bull itself. Additionally semen can be sourced from Australia and even world wide – genetics which would otherwise be unavailable.
  • Access to proven genetics – Typically bulls are purchased at a young age before they have any progeny on the ground. This means that most are bought unproven and unfortunately many will not go on to produce the type of progeny hoped for. In contrast semen can be purchased from a proven sire which can increase the predictability of the progeny and reduce the risk.
  • Obtaining better calves from heifers – Typically producers use very low birth weight bulls over their heifers to reduce calving issues – these bulls are also often low weaning weight bulls and the bulk of the progeny are often culled despite heifers representing the best genetics in the herd. By using an AI program over heifers, a bull with accurate EBVs and proven results can be selected with a low birth weight and moderate-high growth rate, ensuring that progeny are suitable for retention in the herd. Sale animals may weigh 20+kg heavier at point of sale than those from a typical ‘heifer bull’ = 15 x $3 = $60+/head
  • Improved genetic turnaround – By retaining a much larger percentage of progeny out of heifers, genetic turnaround can be reduced from 3 years (a females 2nd calf) to 2 years – an improvement of 50%.
  • Increased use from own bulls – Semen can be collected from your own bull and be used in an AI program at the same time as the bull is joined to another group of cows. This option may be particularly attractive when purchasing expensive bulls to increase number of progeny obtained from him.
  • Increased selection pressure on fertility – In most beef production systems fertility is the number 1 driver of profitability. In order to improve the fertility of a herd, a selection pressure needs to be applied (e.g. selling any females that do not raise a calf per year). An AI program is a great way to select for the most fertile heifers in a cohort that then carries on to the cow herd in future years.
  • Females will be set up for future years – By putting heifers through an AI program they are in a better position to remain in the herd for more years. Whilst adult cows take on average 55 days to reconceive post calving, heifers can take a month longer. This does not leave much leeway for heifers to get back into calf in a tight window post calving. In an AI program, heifers can be joined a few weeks before the cow herd and the majority of heifers will calve in the first week of the calving period. This will give them an extra few weeks to start cycling again, ready to conceive early in the subsequent joining period. This will help your females remain part of your herd for longer.
  • Large proportion of calves born at start of calving period – the average gestation length of heifers in an AI program is generally shorter than usual – therefore the bulk have already calved by the due date. The result is a shorter calving window and more uniform age/size of the calves which has flow on benefits at marking & weaning (less younger animals which may struggle) as well as at the point of sale. On average, calves in an AI program are 10.5 days older = 10kg x $3 = $30/calf born
  • More predictable calving – as discussed above most calves will be born in a rush over a short period which cuts down on time spent monitoring heifers.
  • Less calving difficulties – by selecting proven sires with low birth weights and good ease of calving figures, far fewer issues are generally experienced at calving time. Additionally, gestation lengths in AI females are typically shorter which further helps reduce birth weight.
  • Improved handling of females – running heifers through the yards multiple times over a short period helps significantly to improve their temperament and ease of handling for the remained of their lives.
  • Improved heifer growth/condition – As the condition and weight of heifers is critical to the outcome of an AI program, more attention is generally paid to ensure that they are meeting targets. This often results in heifers being better grown than they may otherwise have been which again helps conception rates as 2nd calvers.

What is involved in an AI Program?

Artificial insemination involves firstly the process of synchronizing the females in the program to all cycle at the same time and then secondly the insemination itself. There are a number of different protocols available which can change depending on age/condition/time of insemination/etc. A typical protocol may look something like the following:

Day 0 – Insert CIDRs + Bomerol Injection

Day 8 – Remove CIDR + PG Injection

Day 9 – Bomerol Injection

Day 10 - Inseminate

As can be seen, there is a large amount of work to be carried out over a short period of time with minimal flexibility to change dates/times. As such it is important that the availability of labour and the ability to process the cattle in a timely manner is considered before embarking on an AI program.

The success rates of AI programs vary widely dependent on a number of contributing factors. As a basic guide we would suggest that 50-60% pregnant would be satisfactory, 60-70% would be a good result and above 70% would be an excellent result.

Generally back up bulls are introduced from 10 days post AI onwards (any empties will re-cycle from 17-24 days post AI) and can be left in for 1-3 cycles. In many cases if upwards of 80% of the females are pregnant from the AI and the 1st cycle of back up bulls combined, the decision can be made to sell the remainder. That essentially leaves a 3-4 week joining period and a tight calving interval the following year.

As mentioned, there are a number of factors that can influence the outcome of an AI program. The most crucial of these relates to the maturity and condition of the females. In most commercial settings, AI programs are generally used on heifers as they do not have calves at foot which can complicate handling/etc. As such it is imperative that these heifers have attained sexual maturity prior to AI. The general guideline is that heifers must be a minimum of approximately 60% of mature cow weight (330kg if MCW is 550kg). This is a minimum figure and ideally the average weight of the heifers would be 380kg+. The nutrition leading up to the program is also important and the females should be in good body condition score and on a rising plane of nutrition.

In most situations, heifers are being joined to calve as 2 year olds. Therefore time is of the essence in getting them to adequate weights prior to joining/AI at 15 months of age. It is important to make an assessment several months in advance taking into consideration the weight of the animals and the anticipated feed available. Weighing heifers in April/May prior to joining in September/October is a valuable tool to assess where the heifers are at. Required daily weight gains can be easily calculated and required feed +/- supplementation can be determined.

What are the costs of an AI Program?

The costs involved in an AI program can be broken down into the following:

  1. Semen costs – this is the most variable cost involved and often ranges anywhere from $10-$50+ per semen straw depending on the stud and the bull chosen. It is up to the clients to source the semen used in their AI program. We can then arrange for transport to the clinic for storage in our liquid nitrogen canisters.
  2. Drugs – we will supply all of the required drugs including the progesterone implant and all injectables. With the standard heifer protocol the drug costs are $25-35/head depending on the program used.
  3. Labour (veterinary) – the cost per head for the actual insemination is $120 (GST Incl). This rate may increase in very small programs (<25 head). Additionally, a visit may be required at the beginning of the program to insert the progesterone devices. This process is relatively straightforward and after a short demonstration most producers feel comfortable doing it themselves.

Please do not hesitate to contact us to discuss further if you think that an AI program would suit your operation either this year or as something to look towards in the future.