Maintaining a Tight Calving Pattern in an Autumn Calving Herd

For the past 25 years, Thompson Harbison. Ballydevitt, Aghadowey has maintained a tight autumn calving pattern in his 120 cow herd.  This is achieved through quite exceptional fertility management.  Cows and heifers calve from mid-September to early-December.  Service starts on 3 December each year and comes to an abrupt halt in early March.  Cows not in calf at this stage will be culled.  Thompson has been able to limit this to less than 10 percent.

Predicted calving pattern for this current year

Maintaining this tight calving pattern without having to cull high numbers of empty cows is achieved by paying attention to the four key areas of fertility management:

Accurate records are the key to good fertility management.  Thompson keeps a diary in the office beside the parlour to note all calvings, heats and services.  This provides easily accessible information on a cows reproductive performance – cycling activity, when is the cow due on heat/ to repeat/ pregnancy diagnosis.  This record system will continue to be used although records are now also being kept on Farm Wizard.  Thompson says with a smile on his face “having kept the records it is also vital to use them properly, this is sometimes the weakness when you are very busy”.

Cow condition has a major impact on fertility.  Late lactation and dry period feeding strategies ensure that the mainly Friesian bred cows calve down in Condition Score (CS) 3.0.  They should lose less than 0.5 units of CS in the first eight weeks of lactation.  In order to achieve this target, every effort is made to maximise feed intake as soon as possible after calving.  Fresh calves are housed in early October if weather conditions deteriorate, as happened this year.

Dry Cows in the three to four weeks before calving are fed 2-3 kgs/day of a specialist dry cow ration.  This allows concentrate feeding levels to be increased more rapidly post calving, thereby helping to reduce the period of negative energy balance in early lactation when the cow milks ‘off her back’

Fresh calved cows are placed on a TMR of silage and home-mixed concentrate.  Although the same ingredients are used each year (barley, soya, citrus pulp, maize distillers and molasses) formulation of the concentrate depends on silage quality.  Cow feed intake is regularly monitored to ensure energy and protein requirements are actually being met and the diet adjusted as required.

Effective heat detection plays a critical role in achieving high fertility standards in this herd.  Time is spent observing cows and heifers for signs of heat from early November (four weeks before the start of the breeding season) until the end of the breeding season in early March.  Cows will not generally show good signs if feeding, waiting to be milked or if there is equipment operating in the area.  Thompson believes the best times for observation are first thing in the morning before switching on the parlour, and late at night.  Cows are also checked after milking times and mid-day.  Thompson believes two important factors leading to good heat detection on his unit are:

One method of evaluating the success of heat detection is by calculating the submission rate.  That is, the percentage of eligible cows due for rebreeding that are actually served in any 21day period.  Fertility benchmarking results for this herd show an exceptional submission rate of 94 percent - well above the 85 percent target set for block calving herds

This farm has operated as a completely closed herd for many tears now, with not even a breeding bull being purchased. All services are carried out by AI making mockery of the myth that there is no substitute for natural service!  Strong emphasis is placed on AI technique with careful handling of straws and good handling facilities for restraining stock at service.  The aim is to provide a clean and stress-free environment for both the animal and farmer when insemination is being carried out.

Conception rate for the herd in the past season was 75 percent - a result of the effort placed on good nutrition, accurate heat detection and sound AI technique.  To put this in context, research carried out by the Agricultural Research Institute at Hillsborough (now AFBI), found the average conception rate to AI in Northern Ireland herds to be about 40 percent.

There are clearly many lessons that can be learnt from this farm and any farmer serious about improving the profitability of their business at current low milks should visit this farm.  As a Focus Farmer, Thompson is happy to host visits from groups of farmers to discuss fertility management in his herd.  If you would like to find out more and to arrange a visit then please contact The Focus Farm Centre (tel: 028 9084 0400).

The skills and knowledge required to improve fertility in your own herd can also be obtained through the Dairy Herd Fertility Challenge training programme.  Contact your local CAFRE Dairying Development Adviser or telephone 028 9442 6756 for further information

Thomson Harbison takes  a look at the breeding board for his herd.  Note the concentration of pins in the bottom left hand corner which confirm the tightness of the calving pattern.