Maintaining a consistent diet for milking cows should be the main objective day-to-day, yet, for several reasons this is often not achieved.
Many farmers and dairy specialists concentrate on increasing the cows dry matter (DM) intake. Whilst maximising DM intake is important, it requires much more than simply dumping a ration of essential nutrient in front of the cows. Providing a consistent diet in terms of nutrients and structure promotes stable intakes and maintains good rumen health.
In order to achieve this, you need to analyse ingredients and diets on a regular basis so that DM intakes can be optimal day in day out. High yielding cows need to achieve at least 4% of their body weight in dry matter intake by 9-10 weeks post-calving. Meeting DM intake targets during this early lactation stage sets the tone for the remainder lactation. Every additional kg/DM eaten by the cow at peak milk production will yield an additional 2-2.5 kg/milk/day for the entire lactation. It is important not to forget that a large percentage of the cow’s performance may be attributed to non-nutritional factors. Therefore, consistent management is as important as a consistent diet.
Larger cows will tend to consume approx. 22-28kg/DM feed at peak feed intake, with smaller cows and first calf heifers between 20-25kg/DM. Regardless of the prime DM intake targets, a cow will only consume as much feed as she has in front of her, thus the regular pushing up of feed is crucial.
By correctly measuring DM intakes and monitoring the number of stock entering/leaving the milking group, farmers should be able to estimate what percentage of the total ration should be fed on a daily basis. Similarly, the daily monitoring of DM intakes can prove an important signal of rumen health, particularly in high yielding cows. Depressed intakes can be an indication of poor rumen health.
A healthy rumen microbial population is vital to the cow. The microbes digest fibre, starch and sugars, converting them into available energy for body maintenance, milk production and reproduction. The microbes also break down dietary protein into ammonia which is used by the microbes to produce microbial protein, supplying the cow with a majority of its protein requirements. An unbalanced and inconsistent diet can cause rapid dietary changes, in turn, upsetting the microbial feed fermenters and decreasing feed intake. A rumen effectively digesting both starch and fibre will produce more fermentation acids that an acidic rumen just digesting grain.
To maintain a consistent diet and to maximise DM intakes, the following must be provided:
- Clean, high quality water to drive strong feed intakes.
- High quality feed - forage quality is the driver of a good feeding programme. Quality forage supports higher and more consistent DM intakes. This is due to its increased usable fibre content, providing greater digestion and increasing essential nutrient availability for milk production.
- Avoid feeding mouldy or spoiled forage.
- Adequate physically effective NDF (pNDF) - high yielding cow’s diets should contain approximately 30- 35% total NDF, with 75-65% respectively coming from the forage. physically effective NDF promotes cud chewing which in turn creates rumen buffer and neutralising rumen pH, thus preventing acidosis. A lack of cud chewing indicates the insufficient provision of pNDF.
- Formulation of a palatable, rumen friendly diet – In addition to peNDF, high quality dietary proteins and starch must be provided.
- Awareness of DM intakes and milk yield – regular monitoring of DM intakes is essential. Fluctuations in DMI and production are key indicators of rumen health issues.
- Application of common sense bunk management – feed should be delivered at the same time of the day and with pushed up a minimum of 4x per day. Feed bunks/troughs should never be empty. It is essential not to force cows to clear troughs before providing fresh feed.
- Monitor the number of cows with suspected acidosis – watch out for gaunt cows, a lack of cud chewing, cows not feeding and lameness. Manure should be consistent and have the consistency of thick porridge.
Martin Hope
Dairy Technical Specialist
