It is that time of the year when local farmers are starting to join their cattle with the help of Zoetis here is some interesting information to have in mind when joining cattle. The standard joining period is 6 weeks for heifer and 9 weeks for cows.

Zoetis recommend reducing joining periods by 1-2 weeks their reasoning behind this is that it allows;

• Reduced time and labour supervising calving overall.
• Extended recovery for cows/heifers.
• Identification of superior calves at weaning and acknowledge heifers to keep and re-join next time for overall herd improvement.
• The overall herd becomes more profitable.
• Increased value per head.

Of course, ideal conditions need to in place to be successful in reducing joining periods and it is always a good idea to get advice from your veterinarian or and stock agent/advisor if this is suitable for your herd.

Factors that affect fertility and joining periods:

• Herd management
• Female nutrition
• Bull management
• Parasite control
• Genetic factors
• Vaccinating against preventable reproductive diseases.

Nutrition –

Nutrition is an important factor in joining as it determines the reproductive cycling activity. Good nutrition will allow heifers and cows to cycle early allowing early conceiving and shortening calving patterns. With adequate feed during the calving period allows for a potential shorten anoestrus interval (the period of inactive sexual activity). Ideally calving females should have a condition score on >2.5-3.0.

Bull Management –

It is recommended by the MLA (Meat & Livestock Australia) a maximum of 2 healthy fertile bulls per 100 cows/heifers for normal conception rates. Insufficient ratio of bulls to cows/heifer can lead to lower pregnancy rates.

Single sire joining is widely practiced in southern beef industry as it does reduce bull injury from fighting in opposition to that it can decrease calving percentages within the herd.

Poor bull management can significantly reduce fertility and conception.

Important things to note with joining bulls:

• Ideal condition score prior mating is 3.0 (min 2.5 – max 3.5) outside of this range could mean the bull is unfit and over-weight that can lead to low sperm count and infertility.
• Venereal disease such as vibriosis is a STD in cattle that can cause early-term abortion and low calving rates. Prevention can be made by culling aged bulls, seasonal mating and vaccinating with Vibrovax.
• Having insufficient number of bulls in ratio to number of cows/heifers.
• Assessing that the bull is physically sound prior to mating.

Preg-testing –

When aiming for a shorter joining period it is important to preg-test early ideally 6 weeks after joining to ensure maximum calving rates.

Increased Value per Head –

Calves conceived in a shorter joining period (6 weeks) will be ~10kg heavier and 10 days older than those conceived in a longer joining period (12 weeks)

In addition, those in a shorter joining period will be less spread out in age which is ideal when it comes to selling.

It is important to note that if you reduce joining period too quickly and without consideration of factors it may result in lower pregnancy rates.

For more in-depth information on this topic please see the following sources referenced below:

Zoetis
MLA