Katie Arrowsmith, Veterinary Surgeon at LLM Farm Vets, who is currently half-way through a Masters in Bovine Reproduction (MBR), shares her learnings from a recent module that brings to light the vital but often underappreciated role that nutrition plays in fertility management.
As farm vets, we’re not typically the first point of contact for nutritional advice. However, our broader perspective can be invaluable when evaluating herd performance. It’s important to understand that managing cow nutrition isn’t simply a matter of feeding them and expecting milk in return. The process is far more nuanced.
They say a cow is fed four diets:
If performance isn’t meeting expectations, these four areas are where we start our investigations.
This is the theoretical diet, meticulously designed by nutritionists who excel at balancing energy and protein levels for an average cow in a specific group. Yet, every cow is unique. Some may be growing, losing or gaining weight, gestating, or lactating. The ration might suit the average cow, but not necessarily each individual.
This is what goes into the mixer wagon. Errors can occur if the wrong silage cut is used, if there’s spoilage, or if moisture content differs from expectations. Precision is crucial, but even small discrepancies can impact the ration’s effectiveness.
Cow intake varies greatly depending on factors like lactation stage, body condition, and feed accessibility. We often assume cows will consume a certain dry matter intake, but obstacles like limited feed space or unappealing feed can disrupt this. Ensuring ad lib access, pushing up feed regularly, and preventing sorting are essential.
This is perhaps the most complex to assess. We monitor cow performance to evaluate it. Are they producing milk as expected? How’s fertility?
Our production reports, derived from milk recording data, can identify ketosis and subacute ruminal acidosis (SARA) risks using the fat: protein ratio. A butterfat >5.5% and protein yield <0.9kg suggest a negative energy balance and potential ketosis. Conversely, a butterfat <2.5% might indicate SARA. Further insights can be gained through faecal scoring and rumen pH testing.
A fat:protein ratio >1.5 may point to ketosis; <1 suggests SARA. Blood sampling for metabolic profiling can also provide valuable data.
If you’re facing nutrition-related challenges or underwhelmed by herd performance, please don’t hesitate to reach out to your veterinary support. We’re always happy to assist in getting your cows back on track.
The widespread dry weather experienced across the country since early spring has impacted forage growth significantly, leading to a short fall of required forage volumes for the winter months.
