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Use key benchmarks to find opportunities in raising replacement heifers

Marc-Antoine Guesthier for Progressive Dairy Published on 31 July 2019

A heifer’s life can be divided into four main periods: newborn and colostrum; pre-weaning; post-weaning; and growing, puberty and pregnancy. Using key benchmarks and well-established protocols during these periods allow producers to find opportunities in replacement programs and allow them to concentrate on changes that will impact profitability.

This article briefly focuses on areas associated with newborn calf care, heifer-rearing protocols and key benchmarks to keep in mind while evaluating replacement program performance.



Newborn and colostrum management

The management of colostrum may be the single-most important item to look at when a newborn calf program is evaluated. Preventing and treating disease are probably the greatest challenges when raising calves.

The calf’s best chance for overcoming disease is to have the highest level of immunity possible. This is only possible if the newborn calf has received an adequate amount of good-quality colostrum.

To improve calf performance, fresh colostrum should be fed within the first hours of life. Colostrum should be creamy in colour, have a consistent texture and be free from mastitis, blood, manure and urine.

All of these factors will affect the concentration of immunoglobulin antibodies present in the first milking of colostrum from the cow.

If blood samples are available, calf serum IgG (immunoglobulin used as a marker of immunity transfer quality) should be above 10 grams per litre 48 hours after birth.


This minimum value is considered as the threshold for efficient immunity transfer, which has been shown to directly impact calf average daily gain (ADG) and mortality.

Studies have shown calves with higher serum IgG (greater than 10 grams per litre) had a 24% increase in ADG and a 61% reduction in mortality compared to calves with lower IgG (less than 10 grams per litre).

Another important practice is the use of a colostrometer to determine colostrum quality. Standard quality values should fall above 22% Brix.

Colostrum with a Brix value of 19 to 21.9 should be mixed with higher-quality colostrum. Colostrum with a Brix value lower than 19 should be replaced by higher-quality colostrum.

Finally, the minimum amount of colostrum recommended greatly varies in the literature. We typically recommend a minimum of 3 litres of colostrum in the first hours to provide 150 to 200 grams of IgG as soon as possible and an additional 3 litres within the first day.

Pre-weaning period

After birth and colostrum feeding, the newborn calf should be housed in a new pen, not too close to older animals, for the pre-weaning period.


The calf should not remain with the cow any longer than necessary to reduce risk of pathogens transmission, as suggested in the Young Stock Signals program elaborated on by Dr. Joep Driessen of Holland.

Many types of housing can be used and support high-performance growing calves, as long as it is kept clean, well ventilated without drafts and minimizes calf-to-calf contact to reduce disease transmission.

Calves need a sufficient amount of dry bedding at all times. If bedding gets wet, calves are more likely to be dirty, lose their insulation ability, become sick and perform poorly.

Sterilization of feeding equipment between meals helps reduce disease transmission. During hot summer days, calf body temperature is susceptible to increase, just like with dairy cows. Make sure the calf always has access to fresh water, a shaded area and good ventilation.

After colostrum feeding, transitional milk should be fed for the next 48 hours. Beginning on the fourth day, the calf should be switched over to milk replacer or whole milk as the primary source of nutrition.

Free-choice calf starter should be made available to the calf by the third day of life and will help development of papillae in the calf’s digestive system.

Forages may also be offered to help with digestive system development. However, recent studies have shown high-quality calf starters better support rumen development early in life.

This is in part due to the fact that fibre digestion will lead to the production of acetate instead of butyrate as major volatile fatty acids used as energy sources in rumen metabolism.

Butyrate is well-known for its positive impacts on rumen development and papillae growth in ruminants. Fresh, clean water should be available at all times, especially during hot summer days.

Post-weaning period

Calves should be weaned once starter consumption is over 1 kilogram per calf per day for three consecutive days. This normally occurs between 6 to 8 weeks old but can also take place sooner.

At this quantity, consumption of feed is sufficient to support energy and all nutrients required for adequate calf growth. During this stage, calf starter represents the most cost-efficient nutrition strategy.

The post-weaning period represents a great opportunity to measure calf performance. Keep in mind: Calves should double their bodyweight from birth to weaning.

They should also reach 15% of their estimated mature bodyweight at 90 days old. These are the first indicators for calf performance benchmarking.

Growth, puberty, pregnancy and the close-up period

Raising heifers is an expensive but key investment for the future of your herd. This is the period where you will determine improvement opportunities and if your animals are performing as expected.

For this reason, key benchmarks should be used to determine heifer performance, starting with the first insemination happening ideally around 14 to 15 months old.

This key indicator is critical to ensure profitability and performance post-calving. Heifers should reach 55% of their mature bodyweight at this stage of first breeding.

Heifers that calve at 22 to 24 months old after reaching 94% of their mature bodyweight have been shown to be the most profitable animals.

Heifers calving at more than 27 months old are more susceptible to calving problems and udder fat deposits, which can result in a reduction in milk production over the long term.

In terms of nutrition, regular monitoring of bodyweight and ADG can keep the heifer-feeding program on track in the same way milk weights and components help us evaluate rations for lactating cows.

Heifers, just as close-up cows, should be prepared at least five weeks before calving. Heifers should receive a pre-calving feeding program and care to ensure ease at parturition and performance for the heifer and health of the newborn calf. 

Figure 1 shows a summary of the expected results for each key period of replacement animal rearing that should be kept in mind while discussing protocols on-farm.

summary of the expected results for each key period of replacement animal rearing

Click here or on image above to view it at full size in a new window.

Technology programs are available today to help you track these important benchmarks and set next goals.


There is a lot of information on proper rearing of replacement animals. Even though many good practices can be used on farms, it is important to keep in mind that setting goals and following key benchmarks are essential to achieve good performances in your calf and heifer program.

Many tools exist to help you measure your performance and create a discussion around animal rearing. These should focus on well-established protocols that allow you to get your animal ready for a healthy and productive life.  end mark

References omitted but are available upon request. Click here to email an editor. 

Marc-Antoine Guesthier
  • Marc-Antoine Guesthier

  • Dairy Technology Development Specialist
  • Cargill/Purina
  • Email Marc-Antoine Guesthier