RESEARCH conducted by the DairyFeedbase project First 100 Days has reinforced the importance of the type of cereal grain and high-quality forage provided during early lactation.
"During the transition period, we know that cows experience a suppressed feed intake paired with increased insulin resistance and lipolysis, increased challenges for the immune system and increased nutrient demand (mainly glucose)," Agriculture Victoria research scientist Dr Rodrigo Albornoz said.
"Poor health outcomes from a poorly managed fresh period can have short-and-long-term effects, like increased health treatment costs, production loss for the first 20 weeks in milk, decreased reproductive performance and increased carryover/culling rates."
A spring 2020 experiment conducted at Agriculture Victoria's Ellinbank Smartfarm fed concentrate mixes at each milking containing base cereal grains, with contrasting ruminal starch fermentabilities.
Separate groups received wheat grain (high ruminal fermentability) and maize grain (moderate ruminal fermentability) at a rate of six kilograms dry matter (DM) per day from calving to 7 days in milk (DIM) and then 8kg DM/day from 8-23 DIM. A third group received the maize base mix at the same rates plus 350 grams per cow per day of a fat supplement. Additionally, all cows had free access to a low fibre lucerne hay.
At the start of the carryover period (24-72 DIM), all cows were transitioned to a common diet of grazed pasture and a wheat and barley grain mix.
In this experiment, cows consuming maize grain, with or without fat, increased intake by about 2kg DM/cow per day, reaching 24kg DM intake by 23 DIM, and increased milk production by about 2kg/cow per day compared with the wheat grain treatment, which reached 22kg DM intake by 23 DIM.
Differences in milk production between treatments carried over despite all cows receiving the same diet during the carryover period (pasture and grain mix).
Metabolic and physical signals control feed intake in dairy cows, with metabolic signals predominant in the fresh period, and they can interact with the type of starch offered.
When more fermentable starch sources, such as wheat, are fed to fresh cows, signals that inhibit DM intake take place faster than when cows are fed starch sources of moderate fermentability, such maize, causing a decrease in daily feed intake.
In research with total mixed ration systems (TMR), the addition of fat with about 30 per cent oleic acid (a long-chained mono-unsaturated fat), has been shown to stimulate DM intake, however, in this experiment DM intake from cows fed maize and fat with a similar percentage of oleic acid did not differ from those fed the only the maize mix.
Dr Albornoz said this might be due to TMR cows having a consistent fat consumption throughout the day versus a pasture-based system where the mix containing fat is only fed at each milking and therefore the digestion and absorption of nutrients may not be in synchrony with the animal's nutrient demand throughout the day.
Dairy Australia major Innovation director and DairyFeedbase co-director Kevin Argyle said: "Once again the DairyFeedbase joint venture has highlighted the importance of feed type and the provision of high-quality forage during the fresh period (early lactation) for production and health outcomes.
"In the spring 2019 experiments, Dr Bill Wales and his team identified gains of about 73 cents per cow per day in the first 100 days in milk by managing the amount and type of supplement fed to grazing cows in early lactation; and a carryover increase of 50 cents per cow per day after they returned to the main herd and were fed a common diet. This new experiment has found additional gains that can be made with feeding tweaks."
Visit dairyfeedbase.com.au for more information.
Want to read more stories like this?
Sign up below to receive our e-newsletter delivered fresh to your email in-box twice a week.