How a dairy farm is using TMR to improve calf health

Feeding heifer replacements a total mixed ration (TMR) from birth is dramatically improving calf health and lowering date of first service on a Cornish dairy unit.

Husband and wife Roger and Wendy Semmens along with their son Adam are expecting to serve heifers up to three months earlier at Little Bosanketh Farm, St Buryan, after switching to the home-mixed ad lib ration in December 2014.

Roger and Adam Semmens

Roger and Adam Semmens

“This ration has cost and welfare benefits”, explains Adam, who is on target to have heifers calving at 24 months – a reduction of six months. Scours have also become a thing of the past.

Farm facts

  • Milking herd of 90-100 calving all-year-round
  • Grazing platform: 18ha strip grazed on 24-25 day rotation – two shifts a day
  • 19ha of maize
  • 28ha of first grass silage and up to 12ha second cut if needed


Prior to the change, calves received 1-1.5kg of calf rearing nuts fed at morning and night (up to 3kg overall), with calf milk replacer fed as standard and hayledge and straw offered ad lib from racks, which tended to be ignored.

However, by combining the same nuts with barley straw and molasses, the Semmens’ replacements now eat up to and above 4.5kg of cake each day after weaning (see table 1 below).

“Molasses is important in the mix for palatability and energy,” explains Adam, who adds that the lower stress system has removed the growth-check previously seen at weaning.

See also: Colostrum feeding

“Calves no longer bellow at weaning and some bigger calves are eating over 4.5kg of cake a day. The point is that some might eat 6kg, but they aren’t scouring.

“Offering the feed ad lib means there is no bullying at the feed trough, we are preventing an acid load on the digestive system as the calves feed little and often and we are bringing our average serving age down from around 18 months to 15 months.”

TMR transition

Calf pen:
Age Regime
Birth – 2 days Calves are with mothers and fed colostrum
2 days – 4/5 weeks “Small amounts” of TMR offered alongside standard milk replacer regime
4-8 Weeks After a month, calves eat around 3.5kg of TMR (includes 2kg of calf nuts)

 Group housing

Age Regime
6-8 weeks Calves are weaned and placed into a group, progressing onto 5.4kg/TMR/day = 3kg of nuts
8 weeks-8 months Heifers intake in excess of 4.5kg of calf nuts without scouring
8 months Heifers are taken up to service on a 80:20 grass:maize silage ration before calving down

Winning formula

The coccidiosis treated nut costs are combined with a coccidiosis drench in early life as part of the farm’s youngstock programme.

“We aren’t seeing problems with coccidiosis and scours anymore,” says Roger. “We aren’t trying to produce bigger cows but we are getting them to the same size faster.

“Rather than looking like pot-bellied calves, they look like small cows, the ration really helps their frame and stature.

Ration ingredients

  • Fed from birth to 6-8 months
  • 1t of calf nut with coccidiosis treatment (£366/t)
  • 400kg barley straw (£26)
  • 400kg molasses (£30)
  • Mix cost = £472
  • 16 calves = £1.40/calf/day

“We tried wheat straw in the mix for scratch factor, but this was too easy to sort and we use a 20mm chop length which allows the straw fibres, as well as the molasses, to help bind the mix.”

Setting them up

The replacement policy at Little Bosanketh aims for a 650kg cow that is robust with good feet and udders and can give 8,500 litres per lactation with butterfat at 4.55% and protein at 3.4%.

Cows are expected to walk three quarters of a mile to some outlying grazing fields. Breeding hinges on Holstein-Friesian genetics crossed to a variety of other breeds, including Dairy Shorthorn, Norwegian Red and Fleckvieh.

“For 650kg cows they aren’t particularly tall,” explains Adam. “We breed something a bit shorter and wider. Rain is often sideways here. They need to be hardy and we are targeting 4,000 litres of milk from forage and currently managing 3,800 litres.”

Moisture matters

With space at a premium around the yard, ton bags are loaded from the Keenan forage wagon and stored in sheds for up to six weeks each containing 250kg of TMR, with Adam stressing that bags be kept dry to avoid heating and moulds.

Currently there are 16 heifers on the ration and bags are lasting three days. This will be different in March/April when 25 calves will be on the TMR, adds Adam.

“We’ve not seen the full effects yet either only starting with it 14 months ago,” he stresses. “Feeding them this way allows us to push more cake through them each day without them getting a huge hit of cake in one go.”