Vet’s Voice by Dave Barz: Marketing muscle
Man am I spoiled. These few cold days have certainly reminded me that winter is rapidly approaching. Usually winter has been a time when our gestating cows have been stressed severely. Couple that with the high feed costs in the last few years, and the problems increased. Recent research on fetal programming in both humans and livestock indicate long term consequences to off spring.
The basic concept of fetal programming involves the fetus and its growth and maturation while it is in the uterus. Nutritional deficiencies and stressors during stages of development of the fetus have resulted in both positive and negative effects on the calf itself and ultimately the future off spring of that calf. Human data sets from the Holocaust and other disasters of war and nature were studied and future problems in the offspring and their descendents were documented. This has resulted in a new term epigenetics. This means environmental factors cause genes to ‘express’ themselves differently though the genes themselves do not change.
How does that affect my cows? In this era of genetic testing we understand that the genes don’t change, but why is there variation? We can identify the portion of the gene which results in the expression of certain characteristics, but we have less control of how those genetics are ultimately expressed in the offspring.
In the past we only cared that there was a calf in the cow’s uterus and never worried about it until it was delivered. When we examine the nutritional needs of a cow we must ask, ‘When is the cow consuming nutrients for herself?” The answer is “ never unless she has a reproductive failure.” Once the cow delivers she is feeding her calf through lactation. Then she is bred while still lactating and even after weaning she is still developing the calf until birth when the cycle starts again. Because she is always consuming nutrients for two and sometimes three individuals nutrition becomes very important.
After birth it is the milk she producers which makes the calf grow to an acceptable weaning weight, but also the young fetus is developing in the uterus. The first trimester of pregnancy is very important because placentation develops (attachment of the calf to the uterus). Optimal nutrition and low stress will result in a more vascular placenta thereby furnishing better blood flow to the fetus. During the first trimester the organs begin to differentiate themselves;
· Lung and liver
· Heart and brain
· Gastro intestinal tract
· Repro organs
· Muscle fibers
These continue to replicate and grow during gestation.
In the beef industry we market muscle. All the muscle fibers are formed during the first and second trimester and no others form later, they merely enlarge. Fat cells develop during the second and third trimesters of gestation but they can also be created after birth. There is no net increase in the number of muscle cells after birth. Research has been conducted on:
· Reproductive efficiency
· Growth rates
· Weaning weights
· Carcass grading
· Feedlot performance and health
Data has shown very subtle changes in nutrition during gestation can affect outcomes of the calf and also future generations. If you want to examine studies contact me at firstname.lastname@example.org and I will forward them to you.
Purebred producers have understood the existence of fetal programming for many years although they never had a name for it. That is why their cows always appear to be over fleshed. Early weaning also decreases the nutritional burden on the cow during the second trimester. This winter feed is inexpensive and relatively easy to assemble. Consult with your nutritionals extension specialist or veterinarian to formulate cost effective management programs which will allow you to maximize the potential of your herd. For too many years we have utilized least cost practices to merely allow your cows to become pregnant. With the value of muscle at this time we need to develop the full potential of your herd. Not only will it result in short term gains, but it will ensure a bright future for your beef enterprises.