Replacement Dairy Heifers – ‘Get it right or pay the price!’

December 13, 2021

Heifer rearing and the associated cost of replacement stock on dairy farms has become more significant on many dairy farms in recent years. This is largely due to increased replacement rates on farms and as a direct result more heifers are required to maintain herd size. This coupled with the fact that Northern Ireland average herd size is steadily increasing simply means more heifers, more facilities, land and labour required for the replacement enterprise.

Countless research has highlighted how strategic management during the rearing period can significantly impact the lifetime performance of the future dairy cow. So, what is a successful heifer rearing enterprise, and what are the key performance indicators we need to look for?

Richard Gibson, CAFRE Dairying Adviser, exclaims “get it right or pay the price!” and explains that statement by saying that“the cost of maintaining any dairy herd is a major cost, it’s basically the cost of replacements less the value of cull animals sold. As a proportion of total variable production cost it is typically the second highest in the region of 3 to 4ppl, with only feed and forage costs greater on most farms”. This is a cost area that needs to be looked at but few do, for a number of reasons, firstly it is largely hidden, unlike costs such as vet bills and dairy sundries. You never write a cheque for ‘Herd Replacement Cost’. It is also not an easy cost to tackle, it requires a clear plan, and in many cases a significant change in production system is required which in turn needs to be planned strategically, and as expected, takes time to implement.

Richard continues that in many cases the individual cost of rearing the heifer to the point of calving, while it is significant, it is not the most important figure. The total number of heifers now required on many dairy farms is now a more significant issue for dairy farmers. Replacement rates on many dairy farms are now ranging from 30 – 35%, just to maintain herd size. For many producers the starting point is to begin recording the reasons associated with culling to allow them to identify the core problems and then set about making improvements.

Richard advises to make sure the heifers entering the herd have the highest genetics possible. Getting heifers from birth to calving is a large investment on any farm and to get the greatest return on the investment the quality of stock needs to be the best possible. The heifers certainly need to be genetically superior to the cows leaving the herd. If possible establish a herd genetic report from milk records, and use this information to inform your sire selection process.

A recent business development group meeting in the Newtownards area established sire selection criteria for the host herd. While the herd was a high yielding herd, the focus for the selection was on cow fertility predicted transmitting ability (PTA), milk component % PTA, and cow stature. The targets used for this particular herd sire selection included; milk 350kgs, butterfat 0.2%, protein 0.1%, fertility index 9.8, and stature 0.7.  Selection of sires this way allows the herd to develop in the most profitable and sustainable direction.

Richard recommends that “the objective on every dairy farm should be to rear heifers to enter the herd at the correct weight and age to achieve the best production and fertility performance”. Numerous studies in Ireland and abroad have shown that calving heifers at two years old improves lifetime performance and reduces rearing costs. Therefore, it is essential to establish clear targets for heifer rearing and monitor performance closely over the rearing period.

If heifers are behind target it is important to look for the causes of poor growth. High quality grass or silage, good parasite control and targeted meal feeding are key to good weight gain. Any heifers behind target now should be separated from the main group and fed accordingly. Now is the time to take corrective action – do not wait until next spring!

Richard outlines practical growth target protocol as follows:

The aim for your 2021 dairy calves in an autumn calving profile is to have them submitted for service in late November/early December 2022. These calves are just at weaning stage now, or possibly just past it. Establish the weight of your replacement calves now, and refer to Table 1 but remember the live-weight targets in Table 1 are based on the mature weight of cows in your herd. It is critical to establish the weight of your average mature cow before setting targets for the replacement stock. Live-weight targets in Table 1 are equal to 30%, 60% and 90% of mature live-weight at 6, 15, and 24 months of age.

So for example, a target mature weight of 600kgs, the replacement heifer calf at weaning age should be 110kgs, then 180kgs at 6 months with a daily growth rate in this period of 0.73kgs/day required. The same heifer at breeding age should be 360kgs with an ADG of 0.7kg/day required, and finally this heifer should calve at 24 months at target weight of 540kgs which is 90% of mature weight target. For late born calves that will be calving at 22 or 23 months the ADG targets in the table above will need to be increased to meet target live-weight.

Richard concludes that “with the current pressure on margins from steady escalation of costs in the sector, it is essential that dairy farmers continue to review all parts of the business to increase efficiency and control costs.  A closer focus on herd replacements can have a large impact on farm profitability, after all it is the second largest variable cost of dairying after feed”.

Generally, there is considerable scope on most farms to reduce the cost of herd replacements with reduced age at first calving, and reducing the number of cows culled.