Heifer rearing may not be perceived as the most important sector of dairy farming, but it is critical for those aiming to calve at two years of age.

However, when you have 5000-6000 young Holstein calves on site at any one time and a staff of 15 to attend to their nutritional and welfare needs, management not only has to be up to the mark but also simple.

It's a policy which appears to be bearing fruit for the Bos Family's Dairy unit which is one of six farms operated by T and M partners' 30,000-cow business providing milk for Select Milk Producers in the United States, and visited as part of an Alltech/Keenan trip.

Here, some 3600 Holstein cows are milked either through a 12-unit robot system, or on a separate site, through a 60-point rotary, while all the heifer calves produced along with those from the other farms are reared on the one unit, which is better known as Calf Land.

Newborn calves are fed from pooled colostrum and don't leave the home farm until they have had at least three feeds, are dry and able to walk freely, roughly 36hrs of age. From there they are transported to Calf Land which has 3000 individual calf hutches situated on sand where calves are fed pasteurised waste milk for the first 30 days in two, 2.2litre feeds per day. Milk is then mixed 50:50 with calf milk until day 58 when they are weaned.

Water and dry feed is nevertheless available at all times and comprises starter whole grains, protein pellets, oats and flaked and whole maize.

"A dehydrated calf can be a big issue here so the first thing we have to do is train the calves to drink and show them where the water is," said herd vet, Jim Roodzant,"

No hay is fed to ensure calves consume a highly nutritious protein diet, although a small amount of straw is used for bedding in the winter.

At day 70, individual calves join a group pen of up to 40 calves and are fed a total mixed ration for a further 100 days, when they are then moved to the state of Colorado – 18hours away, after they have been tested for tuberculosis.

Having grown on, the top end of heifers are AI'd using sexed semen, while the bottom end are AI'd to Jersey sires to improve butterfat and protein percentages. They return to their home dairy, in calf at 22 months, to calf at 24months of age.

"We are looking to breed racehorses not show cows. Our cows have to milk and they have to make money so we aim to calve our heifers at two years of age." Jim added.

According to Jim, 1% of calves die at birth and mortality rate up to six weeks is just 4%, but then calves hutches are thoroughly disinfected between each calf. Like here, scours and pneumonia cause the biggest problems.

At present, cows produce on average three lactations, but with the introduction of robots on one of the family's units, and another 12-robot shed for up to 740 Holstein cows planned, it is hoped longevity will reach nearer four lactations.

Admittedly, the current rotary parlour at Herrema which milks 420 cows per hour has worked well over the years, however, the installation of robots on one site has helped to increase overall milk yields by 20% due to the reduced stress on the cows.

"The high yielders on the rotary system don't getting milked out properly as they are not on the rotary long enough, and if we installed robots there we'd probably find milk yields and lifetime yields would increase," said herd manager, Cory Craig adding that standing time would also be reduced as cows would not have to queue up the same to be milked.

This compares to the Bos Dairy unit where cows are milked on average 2.9 times per day through robots and cull rates have fallen from 40% to nearer 20% due to the reduced stress. Average milk yields have also improved by 3litres per day to 41l.

Somatic cell counts have also been reduced but then the Lely robots give detailed reports of the amount of milk produced each time a individual cow goes through the machine and the amount of milk given from each quarter, thereby highlighting potential disease issues before clinical signs appear.