High fertility, milk solids and positive for milk - Johnstown Castle’s route to functional cows

Strict breeding policies are delivering for the Teagasc winter-milk herd in Johnstown Castle, Co. Wexford. Consisting of 90 autumn-calving cows, the herd has delivered 7,500kg of milk and 600kg of milk solids per cow over the past five years.

As part of the recent Winter Milk Open Day held at the Teagasc research centre, Aidan Lawless, Farm Manager of the Johnstown Castle dairy unit, highlighted how this is being achieved, while also giving insight to the breeding programmes being utilised.

Aidan explained: “We have two herds here – an autumn-calving herd of 90 cows and a spring-calving herd of 50 cows – with both herds being managed as standalone herds. Over the past five years, the autumn herd has delivered an average of 7,540kg of milk and 616kg of milk solids per cow, coming from fat and protein percentages of 4.52 and 3.66, respectively. This level of performance was achieved from a meal input of 1,602kg per cow, with the vast majority being fed in the first 150 days of lactation at a rate of 8-9kg/head/day.”

Table 1: Cumulative milk production

Block calving

Block calving is operated in both the spring and autumn herds in Johnstown Castle, with this limited to 2 x 10 week periods. The autumn cows are currently dry, with this period typically occurring between August 20^th and September 15^th annually. A mean calving date of October 9^th is expected this autumn, with close to 50% of cows expected to calve in the month of September.

Aidan Lawless presenting at the Winter Milk Open Day held in Teagasc Johnstown Castle.

“Block calving is something that makes the management of the herd easier for us,” Aidan explained. “Not only does it concentrate labour, it has a huge advantage in terms of calf rearing. If you can be finished autumn calving by the end of November, Christmas is straight forward in that you don’t have young calves to manage.

“It didn’t happen overnight and probably there are a lot of herds with a 12-14 week calving period, but if you want to tighten your calving pattern, you need to make a plan and focus on your fertility. When the fertility sub-indexes come up, it will give you more scope to tighten the calving pattern.

“We don’t recycle any cows between the seasons. We had a target before of less than 5%, but that’s zero at the moment. Our fertility metrics have improved over the last number of years and that has probably allowed that to happen.

“Our average calving interval over the past five lactations is 370 days. There is a direct correlation between calving interval length and profitability and the closer you can get it to 370 days, the more profitable your herd will be.

“Although we have an average empty rate of 13% after 10 weeks of breeding, our replacement rate is a little high at 23%, we have scope for around 10% voluntary culling and carry enough replacement heifers to have a replacement rate of 20-22% within the herd for trial purposes,” Aidan said.

Table 2: Fertility key performance indicators for the Johnstown Castle autumn herd

Genetics and breeding a functional cow

The 10-week breeding season will start for the autumn herd on December 12^th. In terms of the genetics used, a focus has been placed on producing a high EBI cow that can also deliver from pasture. Maximising the proportion of grazed grass in the diet is a central focus of the herd and having the correct genetics available to turn forage into milk is important. For the 2022 grazing year, the Johnstown autumn calving herd grazed 10.6t of grass dry matter.

Commenting on the genetics in play, Aidan said: “The herd is predominately Holstein Friesian, although some Norwegian Red genetics are present in the back breeding of some of the cows. The autumn herd has an EBI of €218, with €78 coming from milk and €87 from fertility.

“The herd has a maintenance sub-index of €8, which is giving us a mature cow weight of approximately 600kg and they are delivering 1.02kg of milk solids per kilogram of body weight.

“The same genetic selection criteria is used in both the spring and autumn herds. It’s the same cow type we are using in both systems – highly fertile, capable of turning pasture into milk and delivering kilograms of milk and milk solids.

“When you look for high fertility, high milk solids and a reasonable amount of milk, you end up with a functional cow. That’s not our starting point, that’s where we finish with our breeding programme.”

Table 3: EBI profile of the Johnstown Castle autumn calving herd

To achieve this cow, Aidan’s bull team focuses on AI sires with a fertility sub-index of >€100, high milk solids (>35kg) coming from percentages of 0.2 for fat and 0.15 for protein, and positive for milk (€100-200 of a milk sub-index).

Future focus areas for the Johnstown Castle herd will centre on maintenance, carbon and health sub-indexes in addition to the above.

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