
After rearing calves on cow’s milk for 20 years, in 2021 Rosemarie Costar did things a bit differently. She reared 220 calves with Sprayfo Blue calf milk replacer.
Based on the excellent results she achieved, coupled with the financial benefit, she’ll be using Sprayfo Blue again this year.
Rosemarie and her husband Bryce are dairy farmers. Milking 300 cows, they rear approximately 60 replacement heifers annually, plus another 160 calves to sell.
Targeting nil mortality, they wean the calves off milk at 90kgLW and off meal at 120kg, generally at about 12 weeks old.
The Costar’s set-up
Farm type: Dairy
Location: Onewhero, Waikato
Rearing no’s: 60 replacement heifers +120 to sell
Products used: Sprayfo Blue CMR
Target weaning weight (off milk): 90kg
Franklin Vets recommended Sprayfo Blue calf milk replacer (CMR) to Rosemarie for a couple of reasons: one, it was more cost-effective to use than milk from the vat and two, it was a product backed by science.
“We quickly worked out that there was a financial benefit to feeding CMR but that wasn’t the only reason we agreed to try Sprayfo” says Rosemarie. “We felt there was a good amount of science behind the product, it was made from quality ingredients and manufactured quite uniquely. Also endorsed by the vet, we were assured that the calves would be getting the right amount of nutrition.”
Changing from a whole milk system to milk replacer feeding was simple, Rosemarie adds. “I only bought two things: digital scales to weigh the milk powder and a flow meter to measure the milk coming out of the feeder.”
Because she was feeding numerous mobs, she needed to make sure each mob received the correct volume.
“Jaco from AgriVantage talked us through how to premix the milk, the feeding rates and the pros and cons of once or twice-a-day feeding” Rosemarie continues. “I explained our system and he gave us really good tips on how to merge the product into our system. It felt fairly seamless.”
Rosemarie fed her calves Sprayfo Blue from about day 10 (once she ran out of day 3 and 4 colostrum). They were on TAD feeding for three weeks, then OAD until weaning off milk at 90kg.
The only extra work involved with using the milk replacer was mixing up the milk, but Rosemarie says that was minimal.
Rosemarie surrounded by 9 month old Sprayfo-reared calves in March 2022.

“I quickly worked out that it was easier to pre-mix whatever volume of milk was needed the next day. I mixed up the powder with half the volume of warm water, left it overnight and then added the remaining volume of water, hot, in the morning. A quick whizz with the paint stirrer (attached to a cordless drill) and we were ready to feed.
“Giving the milk powder time to soak overnight meant it all dissolved and mixed really easily, we had no lumps at all.”
And did the calves perform as well on CMR?
“We have definitely seen better results with Sprayfo Blue” confirms Rosemarie. “The first thing we noticed was no nutritional scours. I always found that when the calves changed to whole milk from day 3-4 colostrum, we’d get some nutritional scours. Sick calves always require a lot of time in monitoring and nurturing, but this year? Nothing! It was brilliant!”
She puts the lack of scouring down to the consistency of the milk replacer. “Where cow’s milk can fluctuate from one day to the next, the calves on Sprayfo were getting a consistent feed every day.”
“We know that one of the benefits of Sprayfo Blue whey-based powder is enhanced rumen development. We obviously couldn’t see that rumen developing, but the calves were well rounded and looked amazing” says Rosemarie. “They also consumed a kilo of high-quality meal a lot faster than they did on the whole milk system. We have meal available in their pens from day 4 and it was great seeing them getting into it quicker than normal”.
“Our Sprayfo calves have also achieved better growth rates than our calves fed on whole milk in previous years. The mobs were averaging just on a kilogram a day with milk and meal. I did expect their growth rates to slow down once they were weaned off milk but surprisingly, they didn’t. They just kept eating meal and pasture and growing which was evidence to us that they had really good rumen development.”
Finally, the calves achieved the 120kg target weights 10-12 days earlier than previously, so they were weaned earlier. Another cost saving.
This year, Rosemarie will use Sprayfo Blue again. She also plans to add AgriVantage’s Launchpad18 to her toolkit – to enrich maternal colostrum.
She describes her calves as having a good sized frame, being well covered and having good depth to their gut; all the things she looks for in a well-reared calf.
Recommended products
AgriVantage offers a choice of curding or whey Sprayfo calf milk replacers, each one offering different benefits for calf and growth development.

Sprayfo Blue Premium Calf Milk Replacer
Our premium whey calf milk replacer for enhanced rumen development

Launchpad18
Colostrum
Our premium, whole colostrum replacer with high levels of IgG.