When a cow becomes pregnant, some of the nutrients it consumes will be used by the developing calf. There is no other time in the calf’s life when the development of tissues, organs and systems is occurring as rapidly as early weeks in utero.
While the volume of nutrients needed as building blocks for this process is very small, in the first few weeks after conception access to the specific nutrients necessary is critical. Providing these nutrients to the cow to enhance the development of the calf is a concept known as fetal or developmental programming.
The nutrients fed – protein (particularly amino acids), energy (all sources), minerals (macro- and micro-) and vitamins (fat- and water-soluble) – all have very specific roles in the development of the embryo and the fetus.
If even one of these is in short supply during that period, the development of the embryo/fetus can be compromised in some manner that will affect how the animal functions and performs later in life. In some cases, particularly for breeding animals, these effects may be noted years later.
All nutrients are critical to this process. Generally, the nutrients given the most focus are protein and energy. Adequate provision of both these nutrients is important for production of genetic materials. Remember: Both DNA and RNA are essentially proteins.
For proteins to be synthesized, basic building blocks (dietary proteins and amino acids) must be present to create the structure. Energy is required to facilitate the synthesizing reactions, as are enzymes – which are also proteins but involve numerous other components such as minerals and vitamins. The availability of protein has very practical results.
Studies have shown calves born to cows lacking in protein early in pregnancy may be more susceptible to respiratory disease later in life. This is believed to be caused by poor lung development during gestation. Research has examined the incidence of bovine respiratory disease in feedlot cattle.
Fifteen to 45 percent of cattle have been affected by bovine respiratory disease, and 1 to 5 percent of cattle placed in feedlots die from this disease. There is likelihood fetal programming, through proper nutrition, can help reduce the incidence of bovine respiratory disease in these cattle. This may become increasingly important as food animal access to antibiotics becomes more restricted.
But protein and energy are not the only nutrients requiring focus. Minerals also play a role in embryo/fetal development. It was reported in 1957 there was an association between DNA synthesis and the trace mineral manganese (Mn). It was suggested Mn has a functional relationship in the transmission of genetic information. Researchers in 2010 reported Mn seems intimately involved in the synthesis of protein as well as DNA and RNA.
Their results suggested epiphyseal growth plate cartilage was affected during early stages of embryo development due to Mn deficiency in the diet of the dam. This went on to result in malformations of the calf’s reproductive systems and birth of calves with congenital defects in the skeletal tissues.
This infers if Mn is in short supply in the cow, this deficiency will be present in reproductive tissues and may be in short supply during the initial phases of cellular division when the transmission of this genetic information is critical.
To illustrate the importance of certain nutrients at very early developmental stages, researchers in 2001 reported the presence of zinc-, copper- and Mn-dependent enzymes in bovine embryos prior to placental implantation. These enzymes include superoxide dismutase, which is a critical antioxidant and is found in virtually every cell in the body. This study showed this enzyme was present from the very early stages of life.
Implications for the producer
Most dairymen will tell you they are giving increasing focus to management and nutrition during the dry periods prior to freshening and leading up to breeding. In many cases, this focus is driven mostly by the desire to produce milk and getting the cow rebred. For some dairymen, especially in a typical dairy economy, rebreeding and producing a genetically optimal calf often takes a back seat to producing milk.
With high-producing herds, the competition for nutrients between the cow for milk production and the fetus (early and mid-trimester) is significant. Fetal programming emphasis is not only to give attention to the next pregnancy but, also, nutrition and management of the cow have significant extended implications on the life and productivity of the calf.
Extensive research has shown attention to the dam’s nutritional program at conception and in the weeks and months thereafter can bring improved productivity, efficiency, growth and overall quality to both female and male calves.
This is illustrated by:
1. Healthier calves at birth with less scouring or respiratory disease issues (In general, a more responsive immune system, assuming adequate colostrum is available along with proper care after birth)
2. Better growth rates, resulting in heavier calves at weaning
3. A healthier calf throughout the pre-weaning period (This results in lower medicine and vet costs and greater growth performance.)
4. Potentially better bone and muscle expression, resulting in an overall better-quality calf
A study in 2009 reviewed results that maternal nutrition has on calf growth performance. It found inadequate nutrition during the first 90 days post-conception can reduce the number of skeletal muscle fibers, change the composition of muscle fibers, reduce growth potential (skeletal and muscle) and increase fatness of young calves, particularly in non-desirable areas.
Proper nutrients improve fetal skeletal muscle development. Fat cell development may also be enhanced. This has long-term effects such as enhanced marbling potential in calves (used for slaughter). The degree of fat deposition, particularly brown fat, is also believed to improve the younger calf’s thermo-regulation ability.
Finally, ongoing research has shown the pregnant cow’s diet may also signal how efficiently the fetus uses available nutrients. Ideally, there may be ways where we can manipulate the cow’s diet to influence the developing fetus to build muscle, intra-muscular fat cells and other productive tissues (reproductive or mammary gland).
Taking advantage of what we know
1. For heifers prior to initial breeding or cows post-calving prior to breeding, make sure the nutritional program is as complete as possible. Restricting intake and nutrients, particularly for heifers, is not a wise choice.
2. Develop correct supplements that will help meet these requirements as well as maximize cost-effectiveness.
3. Adopt a high-quality mineral and vitamin program.
4. Use of additives such as certain specific yeast products can help improve forage digestibility, improve protein and starch utilization, and help reduce stress effects. Other additives can likewise help nutritional efficiency and delivery of nutrients to the fetus.
5. Ensure a sound de-worming and vaccination program is in place.
Adopting a plan to maximize fetal programming opportunities can go a long way to improving the overall performance of the herd and the profitability of the operation. It can also improve overall long-term performance of the herd and increase the quality of animals for generations to come.
This article was originally published on www.progressivedairy.com and is reproduced with permission from the author.