12 August 2013 Curly question about kale and cows answered

Kale is an important and commonly-grown winter feed for cows in cooler parts of New Zealand.

Cows are often wintered off the main farm on run-off properties as this protects the main farm (milking platform) from being damaged. Because grass doesn’t grow as well in cold weather supplements are used and crops such as kale are grown on the run-off properties. 

Kale grows at lower temperatures than the traditionally-grown perennial ryegrass and produces large amounts of high quality feed in winter.

Innocent Rugoho, a PhD candidate in the Department of Agriculture, Faculty of Agriculture and Life Sciences at Lincoln University has undertaken a study to quantify the daily needs of cows fed kale as part of their winter diet.

“Cows need to be fed well throughout the whole year, and providing adequate feed in winter is very important to farmers who want to ensure that their cows regain their condition and are prepared well for the next calving and lactation. Until now there has been little experimental data on the utilisation and forage behaviour of cows grazing kale in response to changing levels of allowances,” said Innocent.

Innocent compared three equally matched groups of cows fed two different allowances of kale high and low (14 kg and 11 kg dry matter/cow/day, respectively) with a control group (eating grass) and found that the quality of the kale in the feed depended on the ratio of leaves to stems in the kale plants. Cows ate the kale quickly, consuming 8.9 kg dry matter/cow/day in the first three hours after feeding out.

He showed that the quantity and nutritional status of the feed offered in the high kale allowance ensured the largest increase in the body condition score (BCS) of the cows.

The reason why the usual feed calculations put the cows at risk of being underfed was because the low nutrient status of the kale stems had not been compensated for. The high kale allowance of 14 kg dry matter/cow/day ensured a gain in body condition score higher than with the more usual allowance of 11 kg dry matter/cow/day.

As part of this research, Innocent also compared the intake and body condition score of cows offered kale one or twice a day and found that there was no improvement in utilisation or gain in body condition score when feeding cows more frequently.

Innocent came to New Zealand from Zimbabwe after completing an undergraduate science degree. His interest in dairying developed while working at Ngamarua Dairies (a Synlait Farm) in Rakaia. 

His research project is supervised by Professor Grant Edwards and Senior Lecturer, Dr Jim Gibbs .