Current Progressive Dairy digital edition
Advertisement

Laying the groundwork for a healthy, productive calf

Stephen Blezinger Published on 18 January 2013

Scientists have long known that the nutrition and management of a pregnant female has direct effects on the health and growth of the fetus and the baby. Some work at Southampton University in England showed that human mothers who were malnourished during the first half of their pregnancy had children with an increased incidence of health problems as adults, including diabetes, obesity and cardiovascular disease.

In livestock production, lack of proper nutrition often occurs during gestation, particularly during the first two trimesters, even though we know that the bulk of fetal growth occurs in the third trimester.

advertisement

advertisement

In lactating dairy cattle, this can result from competition for nutrients going toward milk production or in heifers, competition for nutrients used for growth and/or milk production.

While variations in the duration and severity of maternal undernutrition do not always result in a reduced calf birthweight, alterations such as glucose intolerance, skewed growth patterns and alterations in structure and physiology have been reported.

In the dairy industry, the primary goals are to produce high volumes of milk with the necessary components in an effort to maximize profitability. A confounding factor exists here, in that during the period when the cow is pushed to reach her peak in production and thus requires a high level of nutrient intake, this coincides with the period when we are also attempting to get her rebred.

Thus, when there is a significant demand for production-oriented nutrients, we are also attempting to achieve conception and initiate embryonic and fetal development and growth.

Many producers recognize the breeding function as a means to an end. The next lactation depends on a pregnancy and full-term delivery of a calf. Often, little focus is given to prenatal care of the calf, and the assumption is made that if the diet is balanced for production, it should also meet the needs for embryonic development and fetal growth.

advertisement

This is where the fetal programming (FP) concept comes into play. Many producers with a strong focus on long-term herd quality will tell you that they are attempting to produce calves that have a set of genetics that will result in improved production and health performance. In heifer calves, this extends to reproductive performance as well.

This can also be seen as having a multigenerational effect, as specific traits pass through a dam to her offspring, then to its offspring and so on. This may be as simple as hair coloring or more complex traits such as milking ability, fertility and longevity – factors that have a direct effect on animal profitability and a measurable economic effect.

To grasp this, we need to understand a few things concerning the developmental process from conception through birth of the calf. First, some general observations:

• The concept that lifetime health is determined in large measure by the environment experienced during development is the single-most important story in human and animal health.

• The process through which a stimulus or insult establishes a permanent response

• Fetal (developmental) programming hypothesis has several components:

advertisement

• Exposure during a critical period in development may influence later metabolic or physiological functions in adult life.

• The ability to improve animal production and well-being by altering the maternal environment holds enormous challenges and great opportunities for researchers and animal industries (producers).

• Provides the basis for establishing and supporting the maximized expression of genetics (Of particular interest to the cattleman is phenotypic expression.)

• Involves long-term management and nutrition

• May be multigenerational

All this can be summarized in one statement: What we do with the cow – how she is fed, how she is managed – sets the stage for how the calf she is carrying performs throughout the rest of its life.

The principles
The principles or basics of the FP concept are fairly straightforward. They include:

1. Fetal programming can be positive or negative.

2. Base genetics of sire and dam must be considered.

3. Initial stage is embryonic attachment to the uterine wall and development of blood supply is critical.

4. Nutrient availability to the developing fetus/embryo

5. Cow stress level

While all these principles are important, let’s focus on two key items:

A critical stage in this process is embryonic entry to the uterus, attachment and establishment of functional utero-placental and fetal circulation. Ruminants have a cotyledonary placenta. This means that the calf is attached to the cow at multiple points, with each of these points providing for the delivery of blood, oxygen and nutrients.

Research has shown that nutrient restriction of cows from day 30 to 125 of gestation resulted in reduced caruncular and cotyledonary weights. Fetal weights from nutrient-restricted cows also tended to be less. Even after correction of the diet during day 125 to 250 of gestation, caruncular and cotyledonary weights were still reduced for nutrient-restricted cows; however, fetal weight was not different.

This suggests that the cow’s nutritional plane at the time of embryo attachment and the related placental development and structures directly affects how these structures develop and can thus affect the flow of blood, oxygen, nutrients, hormones and other blood chemicals from the cow to the fetus.

The flow of these various metabolic components is critical considering that a heartbeat is detectable as early as day 21 to day 22 postconception. In the days following, it has been long known that sequential development of pancreas, liver, adrenals, lungs, thyroid, spleen, brain, thymus and kidney occurs.

These are all critical organs and susceptible to maldevelopment should a restriction or insult to the blood or nutrient flow occur at a specific stage of development.

Cow nutrition also plays a major role. In the dairy cow, during the point in time when breeding and a subsequent conception is to take place, she is well into an ascent of the milking curve. In many cases, she is in a negative energy balance and may be behind the curve on protein, mineral and other nutrient intake as well.

Given this dynamic – where competition exists between the developing fetus and the nutrient demands of high milk production – it is possible and even likely that a shortage of one or more nutrients may exist for optimal embryonic and fetal development.

One specific example could be the availability of the trace minerals copper and zinc, deficiencies of which during developmental stages have been shown to have a direct effect on the calf’s immune system development.

If such a deficiency exists prenatally, after birth the calf may show a higher rate of sickness and thus require more treatment either while on milk or later during weaning and transition.

This means the calf has to be handled more and that antibiotics have to be utilized to treat the illness. This can result in lower milk production response as well as decreased longevity in the herd. Both of these effects will negatively impact the animal’s economic performance and overall dairy profitability.

So at this point the bottom line may be that failure to provide proper levels of copper and zinc (at a cost of pennies) and specific fetal developmental stages while the cow is gestating may end up costing large amounts of money in health costs and reduced long-term performance. Other implications come into play when we consider major nutrients such as energy and protein.

Obviously the maternal groundwork that is laid from conception through birth is important to the new calf and is a complex process. For the calf to develop properly and properly express those genetics that would lead to a long, healthy and productive life, focus needs to be given to the cow’s nutrition and management during this exceptionally important time. PD

Dr. Steve Blezinger is the director of technical services for R & D Lifesciences in Menomonie, Wisconsin. Click here to reach him by email or call (903) 352-3475.

References omitted due to space but are available upon request.

00_blezinger_steve

Steve Blezinger
Director of Technical Services
R & D Lifesciences

LATEST BLOG

LATEST NEWS