On the lower country around Wagga, the last week in July and the first couple of weeks in August is when many producers aim to get the majority of their spring-born calves on the ground.

Calving supervision in winter is chilling stuff.

So it’s great when you hear about something that might make cows calve during the day, rather than at night.

There have been several studies that have demonstrated feeding last thing at night can delay some cows so they don’t calve until later – in this case during the day.

Independent Canadian, British and American studies work have shown feeding expectant cows in the evening delayed their calving until the next day.

In the British study, 162 cattle on four farms compared the percentages of calves born during daylight to cows fed at different times. When the cows were fed at 9am, 57 per cent of the calves were born during the day, compared to 79 per cent for cows fed at 10pm.

In the American work more than 1330 cows on 15 farms in Iowa were fed once daily at dusk, with 85 per cent of the calves being born between 6am and 6pm.

There has been other work, however, that suggests the results are not conclusive.

Motility studies indicate the frequency of rumen contractions is lower a few hours prior to calving. Pressure in the rumen begins to decrease in the final two weeks of gestation, with a more rapid decline during calving.

It has been shown that night feeding causes pressure to rise at night, due to feed volume in the rumen from evening feeding, and decline during the day.

Is it worth considering feeding late in the evening for day births?

Fortunately, the work showing that night feeding does have an effect was published by both the University of Oklahoma and the Alberta Department of Agriculture – both credible sources.

Many producers, however, do actually check their calving cows and heifers at night.

For those who do, feeding last thing of the day should not replace checking the animals, as any gains made from day calving could be lost by lack of attention at night.