Johanna Marsden BVSc MRCVS, Molecare Farm Vets
In calf rearing, Daily Live Weight Gain (DLWG) is one of the most significant indicators of overall performance. Whether rearing dairy or beef calves it is important that they grow efficiently to meet their target bulling weights or finishing weights on time. Standard targets are a pre-weaning DLWG of >0.7kg/day and post weaning DLWG of >0.8kg or >1 kg/day for dairy and beef respectively.
For heifers to calve down at two years old they need to reach bulling weight (60% of their adult body weight) by 15 months old. Failure to reach bulling weight at the right age will lead to lower conception rates due to an increased number of non-cycling heifers and consequently increased costs of rearing. Studies have also shown that for every extra kg of body weight at 6 weeks old they will produce 20.1kg more milk in their first lactation and have an overall higher lifetime milk production compared to later maturing heifers.
Calves have a more efficient feed conversion ratio pre-puberty; therefore, greater growth rates are seen earlier on for the same dry matter intake. So, it is important to monitor growth rates in calves to ensure they’re meeting their targets and make the best use of nutrition resources early in life.
A growth rate of <0.7kg/day can indicate a great number of issues including problems with colostrum management, diseases such as pneumonia or scour, insufficient energy intake or stressors. There are multiple factors that can impact growth rates, and it is crucial to diagnose the reasons for reduced growth rates on your farm working alongside your veterinary surgeon and nutritionist. Following a diagnosis, your vet may suggest changes that include adjustments to nutrition and feed programmes, vaccination protocols if an infectious cause is identified or adaptations to the calves’ environment and management.
The most accurate method of weighing calves is with a digital weigh scale. Weigh tapes can also be used, however, to improve reliability the same person should carry out the weighing each time to ensure that data is collected in a consistent way to provide the most accurate results. Calculating DLWG can be done by using a program or this equation: DLWG (kg/day) = (current weight – previous weight) /age in days
Weighing calves regularly will provide the clearest picture of growth efficiency, especially when taking into consideration any changes in management or illnesses a calf may have had. At Molecare we are able to provide a regular calf weighing service to help our clients to accurately and consistently monitor the growth of their herd.
If you have concerns regarding your calf growth rates, or would like to speak to our team about our calf weighing service, you can call the practice on 01392 872934.