20 July 2004 Do Red Deer Like a Disturbed Night?

Finding out the answer to this question was the task set for Vanessa Crowley for her Bachelor of Agricultural Science honours project with Lincoln University's Agricultural and Life Sciences Division. In June 2004 she was co-winner of a Young Members' Award at the New Zealand Society of Animal Production's Conference for the high quality of her work.

Ms Crowley's research project investigated whether interruption of each long winter's night with one hour of light would stimulate the growth of young red deer, as has previously been shown with sheep.

Her research showed that under the particular light regime she used the answer was, "no" – growth of deer did not respond positively to the short burst of artificial light. This may not be the end of the story, however, as further research could show that deer actually are photosensitive at night but at a different time from sheep.

"The reason why this research is important to the deer industry," said Ms Crowley, "is because venison production depends on the growth of young (weaner) deer and most of this growth occurs in winter. There are limits to animal growth that can occur and this depends on the number of hours of daylight each day."

"Farmers who extend the number of 'daylight' hours for their deer have found that they can reach their slaughter weight up to seven weeks earlier and so they receive the premium prices paid for early carcasses," she said.

Ms Crowley used three different light regimes in her investigation, the control (short day) group (9-11 hours daylight per day), a long day group (16 hours of daylight) and a split day group (the same as the short day group but with artificial light provided for one hour, approximately 16.5 hours after sunrise).

"My results showed that there was no stimulatory effect from the split night photoperiod on the growth of red deer. I concluded that the photoperiod effect that causes the physiological changes in sheep do not apply in deer. Obviously, there are differences in the underlying mechanisms in light sensitivity in these two species," said Ms Crowley.

Ms Crowley's research was supervised by Associate Professor, Graham Barrell.

This work had approval from the Animal Ethics Committee at Lincoln University.

Ian Collins, Journalist, Lincoln University, Canterbury, New Zealand

Janette Busch, Technical Writer, Agricultural and Life Sciences Division, Lincoln University, Canterbury, New Zealand