Using Alfalfa to improve milk output and liveweight gain

Colman Purcell, Nutritionist Dairygold Quality Feeds

Traditionally we value forages based on their net energy and digestible protein content. We usually confine our efforts to these nutrients as we assume these to be the most limiting for milk production or live weight gain.

Some forages and wet feeds that have characteristics other than their protein and energy content that have very significant effects on their feeding value. Alfalfa is one such feed that feeds better than its nutrient analysis would suggest, arising from a number of unique characteristics:

• The level of structural fibre (known as NDF) is typically lower in alfalfa compared to grass silage. Intake is known to be negatively correlated with NDF, i.e. the higher the diet NDF, the lower the intake.
• Alfalfa has a high natural buffering capacity which means that diets containing alfalfa are less likely to cause acidosis. A healthier rumen environment, from a pH perspective, will improve intake and diet digestibility. In fact, a number of trials have shown that there is no justification for the use of chemical buffering agents in alfalfa hay based diets.
• INRA (French Agricultural Research Institute) ascribe intake values to all feeds describing how much of each feed a cow will eat. These values, known as ‘Fill Values’ suggest that alfalfa has a very high intake potential which is consistent with both bullet points above.

Trials comparing alfalfa to grass silage has demonstrated an improvement of 2.3 Kg in diet dry matter intake and 1.7 Kg in milk yield from replacing grass silage with alfalfa. This response is consistent with expectations from the INRA Fill Value system and also feedback from Dairygold customers who have used alfalfa.

Alfalfa vs Grass Silage

Typical feeding levels of alfalfa to milking cows are ~ 5Kg/cow/ day. At this feeding level and with a milk price of 32c/litre, 1 tonne of alfalfa would be expected to return an additional 340 Kg milk worth €106/t alfalfa over and above the price of the silage that it displaces.

At our current offer price of €195/T alfalfa is good value, especially when you consider;

• Alfalfa, unlike home-grown forages, is sold on a ‘per tonne basis’ so you can be certain of the weights purchased.
• Alfalfa is cut at 4 weekly intervals and dried mechanically indoors. This gives a level of product consistency not achievable with other forages.
• The high level and quality of protein that alfalfa brings to the diet allows savings in concentrate protein levels.
• Alfalfa hay can eliminate the requirement for chemical buffers in the diet.
• There was a tendency in the trials analysed where alfalfa replaced grass silage, to increase milk protein yield. This benefit, if it is real, is not valued above.
• Where dry matter intake is increased, we expect improvements in body condition score. Again this is not valued above.

In summary, alfalfa would appear to be a highly nutritious feed for cows and cattle, but with many benefits not immediately obvious from its nutrient analysis.

Colman Purcell, Animal Feed Nutritionist at Dairygold said: “The feedback from members who are feeding Italian Alfalfa has been very positive. Reports continue to indicate that the product is very palatable and is giving responses in milk yield. This is entirely in line with expectations from published trial work with Alfalfa replacing grass silage, cows increased intake and milk yield with a tendency towards increased protein yield as well.”

For more information, contact your local Area Sales Manager or Inside Sales on 022-31644