Rearing More Productive Heifers – Trial Review

May 1, 2016

Rearing More Productive Heifers – Trial Review

Rearing calves well has long been recognised as important in the development of productive heifer replacements.  This concept has been extended more recently to studying the benefits of early rumen development on subsequent growth and milk production.

Agrifeeds/Agritrade have promoted an early rumen development feeding programme using an extruded pre-starter feed RumenX®, and have conducted trials comparing its use to conventional calf rearing systems.  The high degradability of RumenX® is designed to encourage early rumen development, and its low density results in it being retained in the developing rumen longer, ensuring a more is degraded in the rumen.  The restricted milk intake also encourages early intake of RumenX®, and subsequently calf meal, as the rumen develops rapidly.

A recent trial was conducted on a Friesian and Friesian Cross herd averaging 580 kg milks solids per cow.  Traditionally reared calves were fed 2.5-3 litres per meal of colostrum then whole milk twice a day until 3 weeks old, after which the same amount of milk was fed as one feed a day.  The calves were weaned over 10 days, aged around 9 weeks, when consuming 1.5-2 kg calf meal a day.

RumenX® calves were fed 2 litres per meal of colostrum then whole milk twice a day until 3 weeks old.  The milk was reduced to 2 litres and fed once a day until 6 weeks old, after which it was discontinued.  RumenX® was offered at 400 g/day when 1-3 weeks old, increased gradually to 1 kg/day by 5 weeks old, then gradually reduced to zero by 8 weeks old. Calf meal was available from 4 weeks old.  Both groups had access to straw throughout the rearing period.

The calves were combined in one group, and remained on the farm until 5 months old, then grazed on a run off until about 6 weeks prior to calving aged 2 years.  Herd tests recording milk production were performed on five occasions over 9 months during their first lactation.  Milk solids yields averaged 0.21-0.35 kg/cow higher with the early rumen development than the conventionally reared group at each of the herd tests.

The higher milk and milk solids (MS) yields of the early rumen development group were statistically significantly higher in four out of the five herd tests (p<0.05), which is remarkable for an on farm trial, and as both groups had been fed and managed together since weaning.  A rough calculation of the additional milk income per cow in its first lactation was made, using the average MS difference at the herd tests, multiplied by 280 days, and a MS price of $3.90.  This showed an increased income of $290 relative to a cost of the RumenX® of about $65/cow, giving a return on investment of about 4.4:1, and this does not include any savings from decreased milk required during rearing.

These results confirm the benefits of similar trials on other farms, comparing early rumen development using an extruded pre-starter with conventionally reared calves.  Similar improvements in milk solids yields were recorded on these farms.

Comparisons between early rumen development and conventional rearing have been conducted on cows during later lactations, with the former group appearing to outperform the latter group during their 2nd and 3rd lactations.  Calculations based on performance data also indicate the early rumen development cows have improved life time performance.

These trials help demonstrate the importance of early rumen development in setting cows up for improved milk production starting with their first lactation, and continuing throughout their productive lives, which is important when trying to improve profitability irrespective of the milk payout.

As featured in AgriBusiness’ Green to Gold 2016

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About the Author

Julian Waters
Consulting Nutritionist
BSc(Hons), MSc, PhD, CBiol, MIBiol, RNutr, CPAg, MNZIPIM
Julian is an independent, qualified nutritionist who consults around the world. Read More

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