Research and the Developing Fetus
For years cattle industry experts have been talking about the importance of meeting the protein and energy requirements of beef cows especially during the third trimester of pregnancy. This was due to the fact that 75% of the fetal growth occurs during this time period.
So how important is nutrition during the first two trimesters? It is very important that protein and energy needs of the cows be meet at this time because of the affect is has on the developing fetus. New research has shown that the fetus is sensitive to the nutrient level of the cow early in the gestation period. A cow that is being fed a nutrient restricted diet can have a fetus that is undernourished which may result in future health and growth problems for the calf. In other words, the fetus is programmed for performance in later life.
Fetal Programming Defined.
Dr. David Barker from Southampton University in England was the first scientist to use this term. He says that fetal programming is defined as "the concept that a maternal stimulus or insult at a critical period in fetal development has long term impacts on the offspring".
Dr. Barker was studying human health and the affect that nutrition during the first half of pregnancy has on the future health of babies during their lives. His findings showed that mothers who were malnourished during the first half of their pregnancy had children that had an increased incidence of health problems as adults which included diabetes, obesity and cardiovascular disease.
Animal Scientists in this country have learned this concept of nutrition during gestation and fetal programming applies to cattle as well.
According to Kim Vonnahme, Animal Scientist from North Dakota State University, the key to fetal programming is the development of the placenta and the vascular system that supplies blood flow to the fetus.
The critical time period for attachment of the placenta to the uterine wall and the subsequent vascular system for the fetus begins at 90 days after conception. By the 120th day, blood flow to the fetus has increased greatly. During this critical span of days, (90 to 120 days) if the cow is malnourished, the development of the vascular sys-tem between the uterus and the fetus affects the ability of the fetus to get nutrients and oxygen from the mother, thus negatively impacting the growth and development of the fetus.
Of course prior to Day 90 the fetus is developing vital organs along with the development of the placenta so cow nutrition is important at this time as well.
What Happens to Future Calf Performance?
Nutrition Affects First Trimester:
Research studies have shown that calves born to cows that are fed a diet lacking in protein during the early stages of pregnancy, may be more susceptible to respiratory disease later in life. This is caused by poor lung development in late gestation.
If we look at statistics of the incidence of bovine respiratory disease in feedlot cattle, 15% to 45% of cattle have been affected by BRD and 1% to 5% of cattle placed in feedlots die from BRD. Anything we can do to reduce BRD and respiratory problems will be huge for the industry in the form of additional profits. Maybe fetal programming through proper nutrition can help.
Nutrition Affects Second Trimester:
A study was conducted to determine the affects of mid-gestation cow nutrition on subsequent calf performance by the University of Wyoming and the USDA Fort Keogh Livestock and Range Laboratory in Montana.
Two groups of spring calving cows were studied. One group grazed native grasses while the other group grazed improved pastures in the late summer and early fall. The cows grazing dry native grasses were consuming forage low in protein, while the cows grazing the improved pastures with green grass were consuming forage much higher in protein.
The next season after the steer calves were weaned, they were backgrounded and sent to a feedlot at similar weights with data collected after 120 days on feed. The steers from the cows that grazed lower quality native forage had lower daily gains, had lighter carcass weights, had less backfat and had lower marbling scores compared to the steers that were from cows that grazed improved pastures with higher protein levels during the second trimester of pregnancy.
Nutrition Affects Third Trimester:
The University of Nebraska has also conducted studies specifically on the impact of protein nutrition during late gestation on calf performance. A group of cows grazing dry forage in late fall in the Sandhills area of Nebraska were given protein supplements and compared to cows receiving no supplements.
The results showed that calves from cows that were supplemented with protein were healthier, had improved calf performance meaning they were heavier at weaning and had heavier feedlot end weights, and had improved carcass quality (higher marbling scores) compared to calves out of cows that were not supplemented with protein late in the fall.
How About My Replacement Females?
The Nebraska study also looked at the affect of protein nutrition during late gestation on the fertility of heifer calves born to those cows. Heifer calves from cows that received protein supplements had higher pregnancy rates than heifers from non supplemented cows. Heifers from supplemented cows had a pregnancy rate of 93% compared to 80% for heifers out of non-supplemented cows.
In addition, heifers from supplemented cows calved earlier in the calving season, 77% in the first 21 days, compared to heifers from non supplemented cows, 49% calved in the first 21 days.
So yes, according to the Nebraska study, providing adequate protein nutrition to cows during the late gestation period appears to have a fetal programming affect on the reproductive performance of their daughters.
What Have We Learned?
Current research has shown that fetal programming is real and it impacts the future health of calves. It also influences growth rate, reproductive efficiency in heifers, pregnancy rates and initial calving date. In addition, fetal programming impacts carcass quality in the form of muscling and the amount of marbling.
Cattle producers and cattle industry experts have known for years that it is extremely important to meet the nutrient requirements of cows during the last trimester of pregnancy. With this new research we are finding out that it is vitally important to meet the protein and energy requirements of cows throughout the entire gestation period.
If we understand how fetal programming works and how it improves the health and productivity of the calves produced, it makes sense to make sure we are meeting the nutrient requirements of our cattle during pregnancy.
This doesn't mean we have to break the bank buying the most expensive protein supplements available and by not grazing dry forages in the fall. We can analyze the forages and supplements that you have available and balance a ration that meets the requirements of your cows at the least cost.
We also know that there is a need to conduct more research on this topic. There is definitely more to learn. For more information on this topic feel free to contact me.
Source: Jim Church
Contact Information: Jim Church, 320 West Main, Grangeville, Idaho 83530; email: [email protected]; phone: 208-983-2667.
Vonnahme, K.A., Nutrition During Gestation and Fetal Programming., Range Beef Cow Symposium XX, December 11-13, 2007, Fort Collins, Colorado.
Radunz, A.E., Developmental Programming in Beef Cattle and Potential Utilization of This New Science in the Beef Herd., 2011 Minnesota Beef Cow/Calf Days, Publication BP-1103.
Smith, Troy., What We Know About Fetal Programming., American Angus Journal, pgs. 112-113. April 2008
Robbins, Mark., Does Fetal Programming Affect You? Only If You Are in The Cattle Business., Drovers News Source, September 13, 2010.
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