Reaching your herd’s full potential

Tuesday, 11 May 2021

We look at the next generation coming through with our strategic dairy farmer David Cotton who achieves an impressive herd replacement rate of 19%, placing him the top 5% of performers.

A successful replacement strategy can help herds reach their full potential and enhance on-farm performance. It’s more than simply retaining a higher proportion of cows in your herd though. Selecting cull cows and maximising their revenue along with control of replacement costs are all equally important.

Since transitioning the herd at Bridge Farm to autumn calving in 2016, David has worked hard to develop animals more suited to his system. He addressed fertility and lifespan issues, a legacy from year-round calving, and focused on breeding smaller, stronger cows that eat less and maintain production.

His breeding programme is built around maintaining a tight autumn block as well as pedigree - following in his father’s footsteps when he took over the farm 30 years ago. They aim for high milk solids and achieve 625kg per cow per year, with over half the herd producing more than 5% fat.

IceQube monitors are used for heat detection, but David feels observation is still key since it gives the opportunity to know where cows are on heat, which is often the same place in the building. A familiarity and understanding of the cows helps to pick up heat indications, sometimes 12 hours in advance.

Records are kept using UNIFORM-Agri and NMR, used in tandem with a Bray board, which shows the state of the herd and individual cows at a glance - providing it is kept up to date.

As a block autumn calving herd, David uses our herd genetic report to enable careful genomic bull selection using the autumn calving index (£ACI). Their best genetics come from the youngest animals and preference is given to fertile cows that go through the system. The strategy is working as, based on average £ACI, the farm’s older cows rank in the top 20% of GB herds and youngstock in the top 1%.

Explore more about dairy breeding and genetics

Sexed semen is used on all heifers and provides most of their replacements. Cows are only served to a dairy bull when they come bulling in the first three weeks of the serving period, so long as they’re clean and healthy. Any that fall outside of this window are put to an Angus bull. There are no live bulls on the farm, the herd is 100% closed to reduce the risk of disease.

1.7 straws are used per conception, giving more animals in calf than needed to maintain herd numbers. Cows that don’t hold to the block are served again in November to give them a chance to stay in the herd if they are producing over 25 litres.

Some animals inevitably fall by the wayside, but they are few and far between. Data from Uniform along with cell count, mastitis, yield and service history are used to inform culling decisions. Most are lost due to poor fertility; not an absence of bulling but because they don’t get in calf. In the last year, 18 cows left the herd due to fertility, 10 for Tb and six for legs and feet. Inconclusive Reactor tb cows or those marked as Johnnes will also join the list.

The oldest cow in the herd was born in January 2007 and is in her 10th lactation. She was not in calf for two years but was still giving over 25 litres and averages 10,000 litres per lactation.

David’s ambition is to move from the herd’s current 3.2 lactations to four within the next year or so, which he feels is achievable provided they don’t have a TB outbreak.

The farm has a history of being shut down with TB, so any surplus heifers that do not hold, will go as stores to the local market.

An age at first calving of 24 months is set as the target with black and whites born in September and weaned at 56 days. Calf management is a keen area of focus so last year they employed a vet student to help with this critical period and plan to do the same again.

Learn more about dairy calf management

Growth rates are important and once the heifers are turned out and settled, they only eat good quality grass. Heifers are brought in at the beginning of November and fed a ration to get them in calf.

Serving starts on 21st November. The first six weeks are natural service and any not cycling at five weeks are checked by the vet and are either given an oestrogen jab or put on a synchronisation programme. Black and white semen is used exclusively for the first two services. 

The heifers are treated as one group. Any lagging behind are not given special treatment, which makes management easier. Over the years, the block has consistently tightened so that everything now calves between 1st September and 15th November.

Refinement of their approach is an ongoing process as David explains:

“We are getting good results with sexed semen and considering using it exclusively from now on. Genetic progress is faster than culling and we’re seeing the best genetics coming from our youngest animals. A better understanding of nutrition means we are getting more out of the animal too.

“The best cows are the ones you don’t notice. We place a huge emphasis on fertile cows that go through the system. Animals that deliver four lactations will give us the results we want to achieve. A replacement rate between 20 and 25% is optimum so I’ve very pleased to be running at 19% currently.”

See Bridge Farm's key performance figures

David‘s top three tips to tighten the calving block:

  • Get the dry cow transition diet right so they come into the herd clean and healthy. The three weeks prior to calving is one of the critical periods in terms of body condition score and transition diet
  • Get the heifers on the right diet three weeks before serving – they are the future of the herd
  • Don’t serve her to a dairy bull just because you think she is a good cow. The youngest cows will have the best genetics.


Find out more about Bridge Farm

See all our dairy key performance indicators (KPIs)

Explore our other strategic dairy farms