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Monthly Archives: May 2017

Polled genetics – examine the pros and cons

The polled gene in dairy cattle is dominant over the horned gene

Polled dairy cattle trace back as far as pedigree records have been kept. The polled gene in dairy cattle is dominant over the horned gene. Yet horned cattle are still much more prevalent in the global dairy population because few producers ever chose to select for polled cattle as part of their breeding program. This is because the real, economic paybacks of selecting for production, health and conformation traits has traditionally trumped the desire for polled genetics.

Genomic selection has allowed polled enthusiasts to focus on high ranking polled animals to propagate the polled population. However, producers stressing genetic improvement in other traits are also advancing their genetics at an equally rapid rate.

You can add polled as a criteria to your genetic plan, but must keep in mind the financial repercussions of that decision in terms of the pounds of milk and components you’ll give up, and the health and fertility you may need to sacrifice, just to avoid dehorning.

The more recent public awareness about dehorning cattle has made it another hot button topic in the industry. The naturally hornless cattle have gained popularity in recent years because of consumer opinion on the dehorning process, and the side effects they feel result from it. This perception has driven producers to create more naturally polled animals than ever in the past.

The pros of polled genetics

Despite the genetic and performance sacrifices made by selecting for polled animals, many producers do see the opportunity to incorporate polled genetics into their breeding program.

  • Avoid dehorning

You can save dollars, time, and labor, and also minimize stress on your calves by foregoing the need for dehorning. The average dehorning cost varies from one farm to the next based on the chosen method of dehorning, and there is a chance of causing additional stress on the calves during a crucial growth time.

However, it’s important to remember that modern dehorning methods done properly, and at an early age, will nearly eliminate stress on the calves, and will minimize your time and costs.

  • Cater to consumer perceptions

It’s a fact that consumer perception directs many aspects of the dairy industry’s reality. Animal rights activists have criticized dehorning for years, but it hasn’t been until recently that the general public has joined the activists’ view on dehorning as a detrimental process. With increased awareness about this common farm chore also comes increased consumer demands on how they feel farmers should handle it on their dairies.

We clearly don’t want animals with horns running around dairies, so the question is whether to dehorn calves or breed for polled genetics. Unless consumers are willing to pay a premium for milk from naturally hornless cattle, you will likely be leaving dollars on the table by selecting exclusively for homozygous polled sires if you want to ensure no animals are born with horns.

  • The polled gene is dominant

The basics of genetics tell us that since the polled gene is dominant over the horned gene, animals with one copy of the polled gene and one copy of the horned gene will not have horns, and a naturally hornless animal can be created in one generation. It also means it is easier to make more polled animals faster than if the polled gene was recessive.

An animal can have one of three combinations for the polled/horned gene:

PP = homozygous polled means this animal has no horns, an all offspring from the animal will be born without horns
Pp = heterozygous polled means this animal does not have horns, but offspring may or may not have horns depending on their mate
pp = born with horns

If you’re starting with only horned animals in your herd, the figures below demonstrate your results mating cows to a polled sire. The table on the left shows that a homozygous polled bull bred to a horned cow will result in 100% hornless offspring. The table on the right illustrates that a heterozygous polled sire bred to a horned cow will result in only 50% polled offspring.

Punnet square to demonstrate the resulting offspring when a homozygous polled sire is mated to a horned dam
A homozygous polled sire mated to a horned dam results in a 100% chance of polled offspring.
Punnet square to demonstrate the possible resulting offspring when mating a heterozygous polled sire with a horned dam
A heterozygous polled sire mated to a horned dam results in a 50% chance of heterozygous polled offspring and a 50% chance of horned offspring.

The downside to polled genetics

Eliminating the need for dehorning may seem like the right choice for your dairy. However, the genetic sacrifices you will make in order to get to that point cannot be overlooked. Whenever you add extra selection criteria to your genetic plan, you will sacrifice in other areas. Here are just a few reasons to think twice about selecting exclusively for polled genetics in your herd.

  • The continuous need for polled sires
    Like mentioned above, the polled gene is dominant, so you can create a polled offspring in just one generation. What many producers tend to forget is that, at this point, maintaining a population of polled cattle in your herd is much more difficult.

As the images above show, using a heterozygous polled bull will not yield 100% polled offspring. To get to the point of a completely polled herd, and to maintain it once you’re there, you continually need to use only homozygous polled sires. This may not seem difficult, but it leads to the next shortcoming of using exclusively polled sires.

  • Limited availability and variation on polled sires
    Since the prevalence of polled animals within the various dairy breeds is still low, it will still take many generations to genetically eradicate horned animals from your herd if you want to maintain reasonable inbreeding levels.

Even though the number of polled bulls in active AI has increased substantially over recent years, the total number of sires providing that polled gene is still limited. AI companies will only bring in bulls at genetic levels high enough to help you make progress in your herd. And since selection for polled animals has only recently gained popularity, many of the polled bulls are closely related – either from a small group of elite polled cow families or with sires in common.

Even with selection standards in place for elite polled animals, their genetic levels don’t yet match up.

  • Genetic sacrifice and compromised future performance
    Most importantly, at this point in time, polled bulls, as a whole, don’t yet live up to the genetic levels of their horned counterparts. With polled as a strict selection criteria, you will miss out on the best sires, regardless if you select from the genomic or daughter-proven lists. When you figure the amount of production, health and conformation that could be lost by limiting your options to only polled sires, dehorning calves becomes even less of an issue.

Review your pros and cons for polled genetics

As you set your genetic plan keep in mind the pros and cons of selecting exclusively for polled genetics. At this point, the overall genetic and performance levels of horned animals still outpace those of polled cattle. Modern dehorning methods minimize stress on calves, so when performed correctly and at the proper time, it should be almost a non-issue.

On the flip side, you could make a case for exclusively polled sire selection if your milk plant is willing to pay more for milk from polled cattle, or if consumer perception drives your decisions.

Regardless of your selection decision, make sure it aligns with the customized genetic plan you put in place so the genetic progress you make on your farm is in the direction of your goals.

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Sire selection vs. mating

“What is the true value of a mating program?”

Many producers around the world have used a mating program within their herd for many years. However, not all producers have put that keen focus on SIRE SELECTION. If you are in that same boat, you may be missing out on the best genetics to drive profitability on your farm.

Selection vs. mating – which is more important?

Before answering this question, it is important to realize what both of these terms mean.

SELECTION – The process of documenting genetic goals to determine which bulls will help you achieve those goals the fastest. In other words, it is identifying which bulls from the available population will be utilized in your herd.

MATING – The process of choosing which individual bull (of those selected for use in your herd) should be used on each individual cow.

Mating programs generally correct problematic type traits of a cow by using a bull whose trait strengths match a cow’s weaknesses. The goal of mating is to breed a consistent herd of cows. There is great merit in consistency, but it’s easy to see that when the right sires are not SELECTED, then MATING has little impact. If you desire to improve the udders in your herd, and only select sires with poor Udder Composite (UDC), you will not improve udders, regardless of whether your cows are mated or not.

Another frequently overlooked point is that even when you SELECT the right bulls, mating also has little impact! For example, if you select only the best UDC sires for your herd, the effect of individual matings will be minimized. Even if there was no mating program in place, you would still be improving udders in your herd simply by using those udder-improving sires.

Are you sacrificing genetic progress?

The value of a mating program is questioned by many dairy farmers. One in particular, who we’ll call Joe, wants to improve the production and health of his herd. With a nice, consistent group of cows, he has determined that the conformation of his herd is already more than adequate. (This is a common thought. You too can test this in your herd by asking yourself or your herdsman how many cows have been culled for conformation reasons in the past month or past year.) For many years, Joe has had his cows mated, but never put much thought into selection.

In Joe’s case, the mating program was run by allowing any bulls from the available lineup who were at least +500 PTAM and >1.0 UDC to be individually mated to each cow. This process meant semen from at least 20 different sires always remained in the tank. Although the topic of this article is not to discuss how many sires should be used at a given time, clearly having that many bulls increases the likelihood of recording errors and reduces efficiency for the breeders.

So, will Joe make more genetic progress for production and health by continuing his current method of mating without selection? Or would he be better off selecting a group of 5-8 bulls that meet his production & health goals, and randomly using those sires within his herd? Hopefully the answer is becoming clear.

Proof in examples

To break it down in the simplest form, if you want to use two different sires on two different cows, you have two options. The first option, shown below in blue, is to mate Cow 1 to Sire A, and Cow 2 to Sire B. The second option, shown in green, is to mate Cow 1 to Sire B and Cow 2 to Sire A.

Sire vs Cow Comparison

Within the table, you can see the resulting offspring’s parent average figures for PTAM and UDC. As you can see, the offspring genetic average for PTAM and UDC are exactly the same, regardless of which cow is mated to which bull. Mating option 1 will give more consistency between daughters, but mating option 2 yields exactly the same genetic average between offspring.

So once you select certain bulls, the average genetic progress of your herd will be the same in the next generation whether the group of bulls are mated to individual cows, or if one bull is randomly selected for use each day of the week.

In one more example, let’s say Joe does an experiment on his farm. He randomly selects half of his herd to breed to Group A sires, and the other half of the herd to Group B sires. Just for the fun of it, we will say that the Group B sires are mated with a traditional program, and the Group A sires are randomly selected, with one bull being used each day of the week.

Group A: 5 sires that average +100 CFP and +4.0 PL

Group B: 5 sires that average +30 CFP and 0.0 PL

The offspring from Group A sires will average 70 lbs more CFP and four extra productive months in the herd than daughters of Group B sires – even though Group A was randomly bred with no mating program. If both groups were individually mated, the difference between the offspring of each group would still be exactly the same. Daughters of Group A sires will still yield 70 lbs more CFP and four more productive months in the herd than daughters of Group B sires!

What is the value in mating programs?

The quick answer from a purely genetic standpoint is that the value in mating is minimal at best. But there are a couple benefits.

First of all, the mating staff is often the same staff with whom you set your genetic goals.  Having people you trust help you design and build your genetic program is extremely important.

The second value of a mating program comes through inbreeding protection.  We do not want daughters of a given bull to be bred to their brother, uncle, nephew, or worse yet their father himself!  Mating programs do a good job of reducing inbreeding within your herd. However, in order to maximize this value from a mating program you must have two things in good order on your dairy:

  1. Your Identification must be accurate – not knowing the real sire of a cow, makes inbreeding protection impossible.
  2. The technicians must closely follow the mating recommendations. There are way too many herds that go through the process of mating the cows, but very few of those mates are actually followed.


This article is not written to discourage anyone from mating. Mating can help create a consistent group of cows. And for those interested in breeding a “great” cow, protecting faults is important.

However, if inbreeding prevention is the reason for mating, you must ask yourself if it is still necessary to have someone look at cows to mate them. Both a pen mating, which tells which bulls should be avoided on an individual animal, or pen of animals, and a pedigree mating are effective options to minimize inbreeding.

Drive genetic progress – put a plan in place

There are two important concepts to remember when setting genetic goals, and selecting bulls that fit those goals.

  1. We cannot mate our way out of a bad selection decision
  2. When you select the proper bulls to fit your genetic plan, you will maximize genetic progress, even with no individual matings. However it is good practice to utilize a pedigree or pen mating to ensure inbreeding is managed.

The most important concept to remember is that genetic progress is driven by the goals you set and the bulls you use on your dairy – not the individual cows to which those bulls are mated.

So in order to maximize genetic progress and profitability on your farm, be sure to spend at least as much time setting your genetic goals and defining your selection program as you do on your mating program

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Inbreeding: manage it to maximize profit

Inbreeding is a hot topic…

Are you concerned about whether genomics is creating too much inbreeding in the dairy cattle population? Many producers express their concern that sire options to prevent negative inbreeding effects continues to dwindle. We certainly don’t want to mate an animal to her father or brother, but we do need to ask what the real goal is in terms of inbreeding. Should we aim for zero percent inbreeding or rather manage it to maximize profit?

The linear effect of inbreeding depression

As animals become more related to each other, inbreeding depression, or sub-par productive performance, can occur. Inbreeding depression is not ideal. Yet you should still weigh the negative effects against the added profit you could see from greater genetic gains.

Many producers buy in to the common misconception of a magic level of inbreeding that we should never exceed. In reality, we’ve seen results from numerous studies over time that show the effects of inbreeding depression to be linear.

For every 1% increase in inbreeding for a mating, you will realize $22-24 less profit over the life of the resulting offspring. You will see the same cost, or loss, when going from 9% to 10% inbreeding as you see between 1% and 2%.

Genetic progress

It’s well-documented that inbreeding has risen each year since the mainstream adoption of AI. Despite this increase, dairy cattle have made significant strides in production traits like milk, fat, and protein. It’s safe to say that producers would not trade today’s high producing cows for the less inbred, but also lower producing, cows of the 1960’s.

Inbreeding and milk production graph

Real-herd examples

Let’s look into the records of a random cross-section of 10 upper Midwest dairies averaging 1,500 cows, who implement a mating program on their farm. This analysis shows how cows with superior genetics are more productive than cows with inferior genetics, despite the more highly productive group also being more inbred.

In this analysis, cows born between 2005 and 2010, with at least one lactation on record were included. Each individual herd was first analyzed separately, and cows were split into quartiles based on their individual level of inbreeding.

Total # of cows% InbredNM$Milk Deviation1st Lact 305-Day MilkPTA DPRAvg. 1st Lact Preg RatePTA PL
25% MOST inbred from each herd38107.0158649282580.422.51.4
25% LEAST inbred from each herd37844.5121296278750.422.60.9

Here, you can see the difference in genetics, 1st lactation milk production, and NM$ between the top 25% most inbred from each herd and top 25% least inbred animals from each herd. The most highly inbred quartile of cows was also the most genetically superior group of cows in each of these ten herds.

When we measure actual performance, genetics more than make up for inbreeding depression. The NM$ levels, pounds of milk and milk deviations were all favorable for the more highly inbred, but also more genetically superior group.

This doesn’t mean that a mating resulting in 25% inbreeding is the best option. Rather, when managed properly as part of a program, excellent genetics can outweigh the results of inbreeding depression.

You may not realize that current proof values already account for the bull’s level of predicted future inbreeding. Outcross sires see favorable adjustments. Whereas, PTA’s on sires that are more closely related to the average population are negatively impacted because of these adjustments.

Determining matings

Let’s check out an example to see how managing, rather than avoiding, inbreeding is the best route.

The example below shows three sire options to use for a mating in your herd. Sire 1 and sire 2 both offer high Net Merit $ levels. However, their 8% and 6.5% inbreeding levels would be above the suggested 6.25% industry standard. That alone could eliminate them as potential mating sires in many breeding programs. Sire 3 would be a logical outcross mating in this example, resulting in a mere 1% inbreeding.

Sire OptionSire NM$Inbreeding % with cow being bredEconomic loss due to inbreedingAdjusted NM$ for level of inbreeding
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