Fighting negative energy balance to secure a successful mating

ANIMAL NUTRITION Fighting negative energy balance to secure a successful mating

Good reproductive performance is essential for a profitable following season. There are several factors that come to play when setting up for a successful mating, and among these managing body condition and energy balance post calving.

Below covers the ins and outs of energy balance between calving and mating, and what tools can be used to help secure a successful mating this season. Achieving the body condition score (BCS) target of 5 for a mixed aged cow (5.5 for a heifer)1 pre-calving is gold standard on farm, as it has been proven to result in better reproductive performance for the mating ahead. However, even when this target is achieved, managing body condition loss postcalving is still important, and some condition loss is to be expected. This is because she is in a negative energy balance (NEB)- where the energy demand of her body is more than the energy input she is receiving from feed. This is a challenge in every cow, no matter how well she is set up for mating during the dry off, and transition periods. It is mainly due to rumen capacity restrictions of the cow, due to having competed for abdominal cavity space with a foetus until calving and lower dry matter intake pre calving. Not only does NEB result in body condition loss, but it can also impact things from a reproductive point of view. NEB has been found to impact the development of, and quality of the eggs the cow is producing. It can also cause irregular cycling, delayed cycling, and reduced conception rates2. The more severe the NEB, the higher the risk it will have of impacting on a cow’s reproductive performance. Therefore, any attempts made to help mitigate the severity of NEB will serve for the greater good long term. A loss of 0.5–1 BCS is considered an acceptable amount of BCS loss1 . Whilst it is impossible to prevent NEB, the length of time and the severity of the NEB makes a big difference to the cows overall seasonal success. Therefore, the main goal is to minimise this. Factors such as genetics, pre-calving body condition, milk yield and feed intake all play a role in NEB3, and whilst some are out of our control, others are not, so knowing how to influence them is important. Providing a balanced diet that meets a cow’s total dry matter requirements is always the first step to supporting the energy status of a cow, there are additional tactical ‘tools in the toolbox’ to aid in this process. One effective option is supplementing the diet with a dietary by-pass fat 2-4 weeks prior to planned start of mating3. By-pass fats are an ideal way to provide an energy dense fat to the diet. They work by passing directly through the rumen, without being digested by the rumen bugs, and absorbed in the small intestine instead. This means they are directly absorbed into the blood stream to be fully utilised by the animal. They are an ideal option to combat NEB as they can provide a significant amount of energy to the diet whilst taking up on minimal space in the digestive system. SealesWinslow’s by-pass fat solution is Energizer Gold. This product contains 31 megajoules of metabolisable energy per kilogram of product, making it almost three times as energy dense as one kg of dry matter of an average pasture! The product can be used at a feed rate of up to 5% of a ration in a SealesWinslow pelletised feed, to supply it through an in-shed feeding system, or up to 500g per cow per day as a straight product when added to a mixed ration on a feed pad. To learn more about Energizer Gold, and to see if it is the right fit for your farm, speak with your Ruralco store, or your local SealesWinslow TSR.

THIS PROMOTIONAL FEATURE WAS PROVIDED BY SEALES WINSLOW 1. Influence of negative energy balance on cyclicity and fertility in the high producting dairy cow. Wathes, D.C., et al. 2007, Theriogenology, Vol. 68, pp. 232-241. 2. Dairy NZ. Body conditio and nutrition for reproduction. Dairy NZ. [Online] 2022. 3. Dairy Australia LImited. InCalf book for dairy farmers. 2017.