It’s spring silly season at Ellinbank Research
AGRICULTURE Victoria researchers at Ellinbank are still in the middle of the spring silly season, with some experiments winding up and others just beginning.
First cab off the rank this spring was an early lactation nutrition experiment as part of the “First 100 Days” research program.
In this experiment, which is led by Vicky Russo and Dr Bill Wales and runs until January, four different strategies for providing grain supplements during early lactation are being tested in four groups of 24 cows.
Flat feeding rates of either “high” or “medium” amounts of grain for the first 140 days of lactation are being compared to systems in which a high amount of grain is reduced to a “low” amount when cows were judged to have switched from a fat mobilisation phase to one of fat deposition.
Two different ways of approximating the timing of this transition were compared: in one treatment diets were changed when 70 days in milk was reached.
In the final group, diets were changed when cows stopped losing weight and started gaining it irrespective of days in milk ( as judged by daily measurements of live weight).
Results from this experiment should become available early in the New Year.
Next, the second grazing experiment as part of the “Smart Feeding” research program was conducted in October.
An experiment using 40 cows was led by Meaghan Douglas and myself to measure the effect of time away from pasture on grazing behaviour, dry matter intake and the change in the availability and quality of pasture as grazing progressed.
The cows were allocated into five treatment groups of eight and released back to their paddock sequentially.
Over 15 days, one group was walked straight to the paddock while others were sent back at 45-minute intervals over three hours, in the same order each time, thus mimicking what often occurs on commercial farms.
Some cows, therefore, were away from the paddock for six hours per day plus walking and milking time.
To measure grazing be- haviour, cows were fitted with jaw movement sensors and activity monitors to record the time cows spent grazing each day, the total number of bites the cows took each day, and the rate at which cows grazed.
In addition, the n- alkane technique was used to measure the total daily dry matter intake of cows.
Measurements were also made of pasture mass and quality prior to grazing, and then immediately prior to each new group of cows entering the paddock.
Preliminary analyses of the results showed that cows returning to the paddock first produced around 6.2kg more milk per day than cows returning three hours later.
This was despite spending approximately the same amount of time grazing.
Presumably the cows returning to the paddock last harvested a smaller amount of pasture per bite, resulting in a lower intake of lower quality pasture, but this data is still being collated.
Last but not least, an experiment was commenced in early November as part of the “Cool Cows” program led by Dr Leah Marett and Richard Williams.
This experiment, which uses 24 cows, has the aim of investigating four different supplements for their potential to form diets with a lower heat of fermentation that may be useful for feeding cows in hot weather.
Supplements that will be tested include wheat, barley, maize and canola meal.
Information from this experiment could ultimately lead to special “summer supplements” to help relieve the milk loss incurred during heat stress.
These diets will be tested in cows that have been previously identified as being either tolerant or susceptible to heat events, to check for possible interactions between the effects of nutrition and genetics.
SILLY SEASON AT ELLINBANK: Not only is it the spring silly season at Ellinbank Research Centre, it’s also Christmas.