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Calf health and nutrition: Today’s data and tomorrow’s research

Amanda J. Fischer-Tlustos and Michael A. Steele for Progressive Dairy Published on 17 April 2020

We have gained tremendous momentum in dairy calf nutrition research, with publications tripling over the last 20 years. And rightfully so, since dairy calves are the future of the milking herd and how they are fed and managed during early life influences their future reproductive efficiency, capacity for milk production and health.

Although we have made significant improvements in calf management over the past decades, calf morbidity remains a pressing concern for many dairies. While there isn’t a recent study on this in Canada, a 2018 USDA NAHMS study found that current calf morbidity rates reach up to 34% despite the Dairy Calf and Heifer Association (DCHA) reporting that the target morbidity rate for young calves is less than 25%. That same study noted diarrhea and digestive dysfunctions as the major culprits behind these high rates of morbidity, continuing to threaten the health, productivity and survivability of dairy calves.

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To combat this, an abundance of research is published yearly, and automated feeding and precision management technologies are being implemented at a rapid rate. With these developments, researchers and the dairy industry have many exciting avenues to explore in order to develop new and innovative strategies to improve calf productivity and health so we can cut calf morbidity rates by at least 10% by 2030.

Prenatal programming

In humans, we are highly aware of the importance of proper nutrition during pregnancy on fetal development. For example, pregnant mothers during the Dutch Famine gave birth to children who later gave birth to grandchildren who faced a multitude of health problems throughout their lives. This classic scenario makes it clear that maternal effects during pregnancy can alter the long-term health and metabolic status of offspring.

During almost three-quarters of the Holstein cow’s pregnancy, we expect her to produce massive amounts of milk and simultaneously nourish the calf in utero. A 2012 study from Spain found that females conceived in non-lactating dams lived longer, produced more milk in the first lactation and had greater metabolic efficiency than females born to lactating dams. Additional prepartum dam factors, such as heat stress and health, can also influence the calf’s capacity for milk production later in life.

Although this research provides us with a concrete foundation, there is currently little research surrounding the optimal prepartum management and nutrition practices to produce healthy and productive future animals. Advancing this field of study and incorporating the use of newly discovered DNA technologies will enable us to not only develop innovative and effective prepartum management strategies but also study the specific mechanisms that cause these effects.

Colostrum and milk bioactivity

Immunoglobulin G (IgG) in colostrum has been the focus of colostrum research for the past 40 years, with the aim of ensuring passive transfer in newborn calves. Yet in addition to IgG, colostrum contains an estimated hundreds of bioactive molecules that may positively influence calf gut health and development. Certain compounds, such as growth factors and hormones, possess a well-documented influence on calf metabolism and health, while others, such as fatty acids, prebiotic molecules and antimicrobial compounds, have received relatively little attention. These bioactive compounds also exist in higher concentrations in transition milk (TM) compared to whole milk.

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Recent work from the University of Alberta found that calves fed TM after the initial colostrum meal had improved gut development compared to calves transitioned directly onto whole milk. Additional studies have also found that calves have better overall health and energy status when fed TM. There may be opportunity to directly feed TM or to supplement colostrum in whole milk to enhance calf gut development and function. However, we have yet to determine the optimal transition from colostrum to milk and how this can affect both short- and long-term productivity and health.

Similar to colostrum and TM, there is growing interest in the composition of whole milk – both the bioactive and macronutrient fractions – and how this compares to current milk replacer (MR) formulations. In traditional milk replacers, the large amount of whey permeate results in high concentrations of lactose (45% versus 35%) and low levels of fat (18% versus 30%) in MR compared to whole milk. There is emerging evidence that this may disturb gut function and calf metabolism, which may cause concern when calves are fed high amounts of milk replacer pre-weaning.

In addition, the fatty acid profile of MR largely differs from that of whole milk; however, the implications this may have on calf development and health are largely unknown. In the future, further investigation into the ingredient quality and quantity of milk replacer will likely lead to MR formulations being based on ingredient bioactivity, with less emphasis on macronutrient composition.

Optimizing weaning and post-weaning programs

The dairy industry has made great strides in optimizing the weaning transition over past decades, with more and more producers weaning calves gradually and later in life. At present, the initial weeks and months following weaning are essentially a black box for heifer nutrition and management. Dairy producers tend to underfeed heifers at this time: We assume they consume a large proportion of forage, yet it only comprises approximately 10% of the diet. There is a sufficient need to develop step-down strategies from the high-concentrate diets fed during the first year of life. This period is critical in heifer development, and we need strong evidence to support changes to post-weaning diets that maximize growth and minimize overconditioning yearling heifers.

Automated and precision management technologies

The rapid development and adoption of automated scales and feeders provides us with easy access to calf performance, intake and behaviour data. All of this data will ultimately allow us to program feeders on an individual calf basis to increase the efficiency and profitability of dairy operations. In addition, there have been tremendous developments in sensors to characterize the physiology, health and behaviour of calves and cows. Combining these sensors with automated on-farm technologies presents us with the opportunity to improve calf predictions and will eventually lead to automated intervention strategies that will become the future of the calf industry.

This is an exciting time to work and study in the field of dairy calf nutrition and management. Continuously challenging traditional management schemes that may compromise calf health and productivity is fundamental in providing dairy producers with the opportunity to make informed, confident decisions that maximize the profitability and efficiency of their operations.  end mark

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Dr. Michael A. Steele is an assistant professor with the department of animal biosciences at the University of Guelph. Email Dr. Michael A. Steele

Amanda J. Fischer-Tlustos
  • Amanda J. Fischer-Tlustos

  • Research Assistant
  • Department of Animal Biosciences
  • University of Guelph
  • Email Amanda J. Fischer-Tlustos

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