A program where mating is not controlled and bulls are in all year means that calving is not condensed, thus your range of weaners can go from a few weeks old to 6 months old. When feeding weaners in tougher years, this large range in age and weights can make supplementary feeding more complicated, as one product will not suit the whole herd, and they will need to be split. Leaving calves in until a suitable sized herd is on the ground can also lead to extended calving intervals and in some cases, ?lactational?۪ anoestrus of the cows. Anoestrus can be caused by a number of factors including:
Anoestrus means that the cow is not exhibiting regular oestrus cycles due to one of these factors and is described in more detail in PL Senger?۪s ?Pathways to Pregnancy and Parturition?. Anoestrus ultimately affects the productivity of the cow. Anoestrus caused by the presence of the calf-at-foot can result in major problems in uncontrolled breeding situations in terms of productivity of the breeder herd. Prolonged postpartum anoestrus (no return to cycling following calving) can prevent your herd from achieving a 12 month calving interval. Furthermore, keeping a herd that has no controlled breeding program means that employing a preg-testing program is difficult without some loses due to badly timed testing for cows less than 6 weeks conceived. Neglecting to utilise such a valuable tool can result in a less efficient culling program.
Controlled breeding herds boast the practicality of reducing labour, forming larger weaner herd sizes of similar age/weight, synchronising herd health and supplementation programs with branding/weaning, timing the calf drop for the most suitable season, prolonging the life of your bulls and the ability to preg-test safely. In addition, herd health programs can be synchronised with other tasks such as branding or weaning, adding efficiency to the business.
Reducing labour costs, by limiting the number of musters you have to do in order to wean, allows you to tighten your annual expenses and reduce handling stresses on your herd and yourself. By handling larger herds of weaners, you can work more productively. In the event you have to early wean due to a very dry season, a more uniform group of weaners will make supplementary feeding a much easier task as weaners will generally all fall into the same group. This compared to uncontrolled mating, which results in all sized and aged weaners, is a much more manageable task. Doing this will also make your weaner herd more marketable, by having bigger numbers and the ability to draft weaners into select groups which increases saleability.
By pulling all your calves off at once, any lactation anoestrus that was prevalent from the calves will be removed and the cows should return to oestrus within a similar time frame. This, in turn, will benefit the window of opportunity for your bulls, as they can be put in at a specific time following weaning and taken out after sufficient time.
Longevity of your bulls will benefit from this practice as they are not in the paddock with the cows all year round and can rest and prepare for the next breeding season. In preparing your bulls for the upcoming breeding season in a control mated herd, you are also able to feed separate rations to bulls and breeders depending on conditions and targets. By separating bulls and breeders, you can target the changes in nutritional deficiencies that the breeders face across the seasons.
Once bulls have been removed for a period of no less than 6 weeks, you can safely preg-test your breeders to discern empty cows draft off older cows, making your culling practices tighter and more consistent. This removal of dead weight from paddocks will leave your more productive cows with a greater body of feed.
Giving your breeders?۪ access to a supplement that provides extra Phosphorus prior to joining and during peak lactation can help ease the burden of the higher mineral requirements that are experienced. In addition, correct supplementation around calving can aid in preventing postpartum anoestrus by allowing the body to avoid prolonged periods of Negative Energy Balance. Similarly, you have the option of spike feeding breeders or heifers in tougher seasons, depending on your management plans for them. In planning now for the future, you can help to increase the productivity and efficiency of your breeder herd. By assisting breeders with their hormonal status through removing calves and putting bulls in within specific time frames, you will reap more calves per breeder over her breeding life.