Ans 2260 Exam 2

What does C X A mean?

f C means (let’s just say) “Charolais” and A stands for (let’s say) “Angus”, then C X A means a Charolais bull is mated to an Angus cow. Since there is no fraction in front of the C or the A, it implies that each are purebreds. • If there is a fraction in front of a breed “code” then this indicates the fraction of the breed composition of the calf that is comprised of that breed. For example, if one is to mate a C X A, then this will produce a (1/2C, 1/2A) calf. This means the calf is 50% (i.e. ½) Charolais, and 50% (i.e. ½) Angus

What is the difference between composition and crossbred cattle?

For example, C X A produces a (1/2C, 1/2A) calf. This is a “crossbred” calf because it is not the same breed composition as both parents. • For example, a (½ C, ½ A) bull mated to a (½ C, ½ A) cow also results in a calf which is (½ C, ½ A). And yet, this particular calf then is called a “composite” because it IS the same breed composition as BOTH of it's parents.

Heterosis

is created when animals are mated together that are less related than the average of the population. For traits that are controlled genetically by a lot of gene pairs across many loci, this means that some pairs will express non-additive genetic effects. It is these non-additive genetic effects that create performance that is beyond the average of the parents.

What is % of maximum retained heterosis (or sometimes just stated “% heterosis”)?

We calculate the probability that any two genes matched up in a calf at a particular locus come from a different breed origin. For example, if I mate Charolais bull to an Angus cow, then the chances of two genes at any locus on a chromosome pair coming from different breeds is 100%. So this means that the maximum possible heterosis one can expect from using these breeds in various crosses will be expressed in the calf of this mating.

Early weaned Claves will

gain .5 to 1.0 lb. per day faster than nursing.(but requires a good ration)

Early weaning program

Calves Weaned prior to 205 da. traditional age. (3 to 5 months)

Why we early wean calves

Improved repro performance of dams FF Better feed usage for enterprise – (15-20% less energy needed per pair) – Fits fall calving program better – Better during drought years, too FF Better feed efficiency FF Better carcass quality FF Better for retained ownership

Why not wean claves early

May be more resource demanding: facilities, laborlabor – Calf illness, drylot, handling, – High quality feeds needed earlier, longer FF Early marketing of light calves (if feed runs outEarly marketing of light calves (if feed runs out FF Non-standard performance valuesNon-standard performance values – Not 205 da. wts. – Poor eval of MMilk on dams FF May not be feasible in western grazingMay not be feasible in western grazing programs (earlyprograms (early ““rounduproundup””)) FF Others?

Fenceline Weaning

Calves removed but allowed to hear, see and smell dams.

Fenceline weaning advantages

Calf Behavior – Less walking, bawling FF Calf PerformanceCalf Performance – Greater growth at 2 and 10 weeks post weaning – Feed quality dependent FF Calf HealthCalf Health – Immunity acquisition same for both groups

Creep Feeding

Supplemental feed energy to a calve pre-weaning

why creep feed

added weight FF less weaning stress FF supports early weaning program FF purebred bull growth expression

Why would a producer pay the cost of properly preconditioning a calf?

including the desire for someone else to do the work ( contracting the labor out), insuring a more healthy calf at marketing time and to access certified preconditioned sales.

Then, the next question here is why would a feedlot operator pay a premium (i.e. a higher price) for properly preconditioned calves

Preconditioning reduces the rate of illness, stress and death when animals are brought into the feedlot BECAUSE an immune system is established prior to the stress and exposure caused by marketing and transport.   Illness incidence is reduced because the immune system is up and running prior to the exposure.   If the calves were processed at delivery, then there would be no immune system in place prior, and the calves will become ill at a much higher rate.

7 way clostridial vaccination”

A vaccination that protects cattle against seven types of clostridial diseases, which can cause severe illness and death.

7 types of clostridial infections

histophilus somni

infectious bovine rhinotracheitis

para influenza - 3

bovine viral diarrhea

bovine respiratory syncytial virus

mannheimia haemolytica

haemolyticum

Redwater Disease

chauvoei 

Blackleg

novyii

Infectious necrotic hepatitis (Black disease)

There are other mandatory practices applied to the calf besides vaccinations in order to be Iowa Green Tag Certified Preconditioned.  Name two. Not talking about paperwork administration here, but physical applications to the calf.

Dehorning, Castration

There are also several important dates/time frames to which to adhere in order for the certification to be valid.   Name a couple of these.

certificate not administered until after 30 days of weaning, mandatory procedures done at least 3 weeks prior to shipment.

Iowa Certified Green Tag and Gold Tag Preconditioning programs have some different requirements. What distinguishes the gold tag certification from the green tag program?Be complete in noting the differences.  

Gold tag requires booster vaccinations, and to be weaned at least 60 days before certificate is issued, instead of 30 days for a green tag certification.   On older certificates, 45 days is noted for the gold tab program, but this was corrected in lab.  Is best not to take answers from old keys without verifying them.

Another very popular and common preconditioning program in the United States is called the “VAC45” program.   For what does the acronym “VAC45” stand?

VAC stands for Value Added Calf and it requires a 45 day period post weaning before calf is marketed.

Dr. Hiscock or Hindman talked about other national programs like this that mimick the success that we have seen in Iowa with our Certified preconditioning program.

a.       In your reading, “BRD”, sometimes referenced as “shipping fever”, is mentioned a lot, and this was also discussed in lab.   Just to make sure we are all on the same page, define “BRD” (acronym and definition)?”

No, not specifically because this is a complex of possible disease organisms and other stresses that can cause the condition of BRD.   There is not one single cause.  There are products that certainly mitigate the causative agents.

There is not just one specific vaccination that takes care of all of “BRD”.  Thinking of what BRD is, then why is this the case?

Not one because there are numerous causes of the condition often refered to as BRD, including bacterial and viral organisms, shipping stress and unfavorable respiratory conditions such as dust.

Why did Dr. Hiscock indicate that all injections were to be given in the region that falls directly in front of the shoulder and higher on the neck (often referred to as the injection triangle), and why did he recommend that all those injections be given subcutaneously? in

Adherence to the Beef Quality Assurance standards (in other words to avoid creating abscesses in valuable meat cuts)

As the manager, I want to know if the cow is bred or not so that as the manager (aka the allocator or resources), I can

can sell them (cull) from the program so that we are not paying for carrying costs (mostly feed) for a cow that is not going to produce income.

Why is it likely that Joe would not use the blood test method?

A blood test can give a false positive reading caused by a recent abortion. It does not typically create false negative tests by the way as some have eluded on their homework.  Another and greater problem is that cows that are open will not be identified until a couple days later, and so this will require a resorting of cows to sort off the open cows (a chore that would be accomplished immediately when using ultrasound or palpation) and this of course represents for many to much labor and handling,

specific benefits to a manager gained from using ultrasound – benefits that can’t be gained as accurately or at all from a simple physical palpation

earlier detection

aging of the fetus

sexing of the fetus

detection of twins

Why is it useful to ‘age a fetus’?  Name two benefits that a producer can gain from this information.

To know when cows are to calve so that one can be prepared, sort into calving groups or related ideas.

To age the fetus means you can tell who the sire is – if a clean up bull was used after an attempt to AI, that is.

All of the information that one can gain from ultrasound applications is not really all that useful to this kind of producer. Why is that the case?

A producer can gather this information. Gender will allow producer to know his replacement potentials.   Early detection saves feed costs (21 days earlier or more per cow culled), and certainly age of fetus predicts both calving dates and perhaps ID of sire if breeding pastures are managed tightly.   Many large producers though do not really care about his information too much.  There is not much need to harvest this information if most calves are just going to the feedlot, or there is not much need to worry about numbers of replacements.

Now let’s say this large commercial producer, for some reason wants to know all of this potential information anyway. Then what is the biggest challenge for this producer being able to obtain this information?

In order to detect early and also to determine gender, sometimes age, one will need to process the cows through the chutes two times.   That is simply too much work for the information gained.  IE commercial producers are not going to take the time, stress and so on to accomplish this in most any case.  

have a calving season that lasts at about 42 days.  Let’s say that Joe Boviden’s season is currently more than 100 days in length, and it starts a bit later in the year than this producer wishes.   Describe how Joe could use the information gained from ultrasound pregnancy checking technology to improve his calving season situation?

Some might feel that if cows are preg checked early and found open, one can breed them again and get them in the breeding herd.   However, I think this will likely not result in a shorter season, but probably a longer one.  So, this doesn’t address the plan of the producer The situation here is that the producer already has the cows bred but would like to use ultrasound information to shorten the calving distribution of the herd.  So, he will identify late bred cows and simply sell them.  He can do this because ultrasound can predict the age of the fetus.  He will not abort his cows (no one would want to do this).  A bred cow will sell for more than a cull cow, and the average season will be shortened in the remaining cows of the herd.

At ISU, our system is more productive than an average system, so choosing pounds of dry matter per inch per acre above 200, more likely 400 or more is much more appropriate and expected for this assignment. Since there are 15 paddocks, leaving the cows on any paddock of average size for more than 2 days will allow grass in other paddocks to mature.

400 lbs. 6 inches 11.4 acres .5 /1300 .03 * 2 day= 175 cows

171/15 paddocks= 11.4 acres/paddock 

ISU system= 400lbs dry matter per inch/acre 

15 paddock= 2 days per paddock 

400lbs X 6in x 11.4 acres x .5 / 1300x.03 body weight x 2 days= 175 cows

The grazing season typically ends by the end of October in Iowa. But if we want to extend the grazing season later than this in the year, what grazing strategies would accomplish this? We need to provide the client with 2 possibilities here. Please note that feeding silage, hay bales and etc. are not grazing extensions. They are providing stored feeds – not the same.

Utilize stover (strip graze it is best) as long as possible after grass is not available, then move cattle to stored feeds for remainder of winter. Also possible is plans for stockpiled forage usage from grass, or use of tillage/cover crops after frost such as turnips, radishes, or small grain forages

Why is strip grazing not considered rotational grazing?

Strip grazing is NOT rotational grazing because one isn’t going to return to a previously grazed paddock and expect regrowth. It is most often used on crop residues or stockpiled forage.

n the context of grazing systems, explain what is meant by stockpiled forage. Hint: stockpiled forage is not a haystack or a silage pile, and to just say that feed is stockpiled does not answer the question or just repeats the question

This is forage that is left in the field for grazing after the first frost. Hay or silage does not count. It is not what grazers are talking about with the practice of stockpiled forage.

When we talk about 300 lbs. of dry matter per inch per acre, what do we mean by ‘dry matter’? Don’t say “water removed”; for example, silage is 65% dry matter but we did not remove the water to say this. Therefore, what does it mean when we say that a feed is a certain % dry matter?

Dry matter means that rations are balanced by not considering the variations in water content of the feeds.

Will the rate of rotation (aka how fast do he moves cows between paddocks) typically be faster, slower or no different in the in the summer than in the spring? Explain why this is the case.

The rate must slower as grass grows slower and so needs more time to rest between rotations.

Why should utilization rates preferably be no more than 60% in most cases in a managed grazing system? Hint: Think about the plant. What is the word that captures why a leaf needs at least 40% of its surface area?

to allow leaf surface to remain so plants can photosynthesize. The key word here is to photosynthesize. Many people referenced needing more recovery time. This is not the question here – it is utilization rate.

Why do I need more paddocks if one plans a higher utilization rate?

To allow more time for rest during rotation. Time is the key issue here – rotation rate.

In the context of grazing systems, explain what is meant by “swath grazing”? When is it employed specifically?

Swath grazing, a means of extending the summer grazing period of beef cattle right through the winter, is like a frozen TV dinner for cattle. Feed crops — like barley, triticale, or corn — are planted in the spring and cut in the fall.

In the context of grazing systems, explain what is meant by “cover crop”. Hint: Your answer should not reference the obvious situation that the crop is ‘covering’ something. That is not the point. While it is true that cover crops can enhance soil quality, that is not the point here either.

These are annual forages (not perineal is the key) that are very high yielding, easy to establish and improve soil as well as provide a grazing source after frost, thus extending the grazing season. Forages such as annual rye, turnips, millet, etc.

When we choose say 400 lbs. of dry matter per inch per acre in the determination of stocking rate, what are say three factors that lead us to choose this value instead of say 200 lbs. of dry matter per inch per acre?

One needs to reference the criteria that are used to determine the ‘qualty’ of the pasture (as indicated on the notes and handout in lab). For example, cite erosion, weeds, less density, less diversity of forages in the stand, uniformity of use, and so forth. We used this to determine the appropriate value of pounds of dry matter per inch per acre for our calculations