Given the current market conditions, dairy farmers have a huge incentive to utilise and incorporate spring grass into the diet. Grazed grass is acknowledged as the most cost effective feedstuff available, however, it is not without its limitations and challenges.
If it is not correctly managed and balanced, it can end up causing nutritional and metabolic issues. There is no one-size fits all when it comes to managing cows at grass. Each farm needs to assess its own resources and look at what can be practically achieved.
Key considerations when turning cows out:
Early Turnout Criteria – If cows are batched and ground conditions allow, farmers should implement the following early turnout criteria to select suitable cows for grazing;
- PD+ in calf
- < 30 litres milk production
- 100+ Days in Milk
A gradual approach to turnout, with part-time grazing initially, ensures a smooth transition to full-time grazing, with minimal digestive upset and performance loss.
Intake Is King – Potential milk yield from grass varies on every farm and is largely driven by grass intake. There can be significant fluctuations in grass dry matter and quality depending on weather conditions and grazing management.
Under ideal conditions cows can consume 7 – 8kg DM from grazed grass on daytime grazing. It is advised to maintain TMR feeding at night until grass growth rate matches cow requirements. TMR access should be restricted one hour prior to turnout to ensure cows have an edge to their appetite.
Minimising Milk Fat Depression (MFD) – MFD typically occurs on the second rotation in full time grazing herds due to an combination of factors such as low physically effective NDF, high sugar levels and elevated levels of polyunsaturated fatty acids (PUFA’s) in spring grazing swards.
These factors can negatively impact rumen function, resulting in a shift in rumen fermentation patterns, lowered rumen pH and increased passage rate. Whilst it is hard to avoid MFD at grass entirely, it can be minimised by ensuring a gradual transition to full time grazing, buffer feeding chopped straw or silage, feeding a maximum of 4-5kg per milking and including AcidBuf and ActiSaf yeast to stabilise rumen pH.
Excess Protein – Lush, leafy spring grass can often have a very high crude protein content which is mainly rumen degradable protein (RDP).
Rumen microbes are unable to utilise excess protein, particularly if there is a shortage of fermentable energy available. Converting excess protein to urea can have an energy cost equivalent of more than two litres of milk production.
Fane Valley offers a comprehensive range of low and medium protein dairy feeds that can effectively compliment any grazing system.