Inoculants Help Achieve Maximum Use of Home Grown Forages

September 1, 2015

Inoculants Help Achieve Maximum Use of Home Grown Forages

It is important to maximise growth, conservation and utilisation of home grown feeds, as farm overhead and running costs attributed to them cannot be avoided.  Repeated dairy industry surveys and competitions (Dairy Business of the Year) have highlighted this as a major driver of farm profitability irrespective of farm system (1-5).  This is even more important in a low payout year, with constraints on cash flow limiting opportunities to purchase additional feeds.

Maximising home grown resources includes, growing high quality feed, conserving surpluses, and utilising them as efficiently as possible for maintenance and production.  This article considers the aspects of forage conservation and diet balancing.

There are three aspects to silage quality; nutritional quality at harvesting, rate and type of fermentation, and hygienic quality (contamination).  Poor management and practices can result in forage losses in excess of 50%, rendering it an unprofitable exercise.  However, with good silage management, and use of appropriate and effective inoculants these losses can be reduced to as little as 15%.

Low nutrient value silages incur similar costs to high ones, but support much lower levels of production, resulting in a lower income, or require more purchased feeds to maintain production.   There are two main consequences of poor fermentation, being losses of nutrients during ensiling, and unpalatable and poorly utilised silage when fed to stock.

Controlled trials have demonstrated that stock ate more silage, and performed better (after accounting for the extra silage consumed) when fed well made inoculant treated silages, even though laboratory tests were unable to distinguish these from untreated silages.

The benefits were due both to improved palatability, and efficiency of utilisation of energy and protein, with recent trials indicating increased microbial protein production in the rumen.  The net result is that using proven inoculants have been demonstrated to retain more silage (2-6%), that is used more efficiently (i.e. increased utilisable MJ ME/kg DM).

Good management during harvesting and ensiling will help with hygienic quality.  This can be enhanced by including an inoculant containing a specific strain of Lactococcus lactis bacteria, which reduces the risk from thermoduric bacteria, by producing nisin, a bacteriocin that inhibits clostridia.

A positive return on investment from using a good inoculant is generally achieved by reduced dry matter losses during ensiling.  Further benefits are accrued due to reduced losses during feed out, less thermoduric bacteria, and more production per kg silage DM.

As featured in NZ Dairy Farmer

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