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Fertility: You Get What You Breed For


How often have you heard a 4H leader, FFA member, classifier or show judge say a heifer or cow must have slope from her hips to her pins and be wide in the pins because that’s what we need for good fertility? Yes we have all heard that many times. But is it true? Could it be that the Holstein bloodlines we have selected were poorer for fertility than other bloodlines we left behind half a century ago? And that rump conformation has a low correlation with fertility.

A Colorful Opinion

Something we can all agree on is that the fertility levels in our herds, the world over, are not what breeders would like them to be. I well remember just a year ago when I had a discussion with an old time Jersey breeder. True to form he was telling this Holstein guy that Holstein breeders have ruined the breed. Sure higher butterfat and protein yields and udders much higher off the ground were great moves but why the excessive stature, very flat and deep rear rib and the demand that animals be tall in the front end when nature did not make them that way? “Jersey cows don’t need to have sloping rumps in order to quickly get back in-calf. So why do Holsteins need sloping rumps?” His bottom line was that by going for the tall skinny cow syndrome we have selected against reproductively sound females. His concluding statement was “You are breeding cows not runway models.” Think about it, shorter, rounder cows that may give a little less milk but get in-calf quicker are very likely preferred by milk producers to the tall, deep rear rib, walk uphill ones.

Have we won a Little but Lost a Lot?

Have we selected our Holsteins for the ones that do not quickly get back in-calf? Is it possible that our breeding strategies have taken us in a wrong direction when female fertility is frequently the biggest cow problem that breeders have? (Read more: How Healthy Are Your Cows?)

Certainly over the past half century the average production of Holsteins has doubled. And yes in the past decade we are seeing more outstanding scoring (type classification) cows. And the winners at the shows are super cows with awesome mammary systems.

However whether it is genetics, nutrition or management, our calving intervals are longer and pregnancy rates are perhaps half what they were forty years ago. As well with the need for breeders to focus today on profitability there is the need to replace high cost manual labour with technology and there are moves ahead pointing to less use of drugs and medicines for food safety reasons. Therefore we need to find some way to put reproduction efficiency back into the Holstein cow. And do it by selection rather than by cross-breeding.

Skinny at Odds with Conception

Research and breeder experience has brought to our attention that cows that have above average body conditioning get back in-calf quicker and with less trouble than cows that sacrifice their body condition due to high yields, poor nutrition, inadequate transition cow feeding, poor conformation, … or maybe some combination of all of those.

The Billion Dollar Question

So I ask. “Now that we have sire and cow indexes for Daughter Pregnancy Rate (USA) and Daughter Fertility and Body Condition Score (Canada) are breeders using those indexes in their Breeding Programs?”

Bulls That Get Used

The Canadian Dairy Network, last week, published the thirty Holstein sires with the most daughters registered in Canada in 2012 (Read more: Canadian A.I. Market Share and Most Popular Sires for 2012) accounting for 40% of the total registrations. The remaining 60% were sired by 5900 other bulls. The Bullvine decided to study in some depth the 20 sires with the most registered daughters in Canada in 2012. Those twenty sired 35% of the females registered which should be a good benchmark for where the breed is heading.

Table 1 Sire Comparison – 2012 Daughters Born vs. 2011 Top Sires Available

GroupLPIMilk (kg)Fat (kg / %)Protein (kg / %)CONFMSF&LHerdLifeDFSCSUdepthCA
20 Bulls-most registered 20122075103160 /+.21%41 / +.06%15128105982.894s102
20 Bulls - top in 20112392139367/+.16%55 / +.07%101091081022.874s104
Difference-317-362-7-1452-1-3-4-0.020-2

Table 1 compares the twenty sires with the most registered daughters in 2012 to the top twenty Canadian proven LPI sires available to Canadian breeders in 2011. The short answers to the comparisons are: breeders use sires with lower LPIs, less production, more type, less fertility and less Herd Life than the very top LPI sires that A.I. organizations marketed. The shocking truth is that ten of the top twenty most used sires were below average for their Daughter Fertility (DF) indexes. One of those twenty sires had a DF index of only 88 while the top two sires were rated at 107 & 106. High (top 10%) but not overly high.

In case you are wondering if this is a Canadian phenomenon you can refer to a recent Bullvine article (Read more: Top Sires North American Breeders Are Using). The sires with most registered daughters in the USA have the same deficiency in their genetic merit for female fertility. Six of the top ten bulls with the most registered daughters in the middle half of April 2013 were below average for Daughter Pregnancy Rate. Different country same story.

Let’s take the Bull by the Horns

Even though we have only had fertility indexes on bulls for a few years, we as breeders are not using them to genetically improve female fertility in our herds. And it likely goes beyond that – are our A.I. organizations using them when selecting the parents of the next generation of bulls? After all over 90% of the genetic improvement in a herd comes from the sires used.

Fertility Sires

Sires do exist that top the April 2013 North American TPI™ and LPI listings and have fertility ratings in the top 25% of the Holstein breed. Breeders wishing to genetically improve their herds for female fertility should consider the following sires:

Table 2 Top Sires with High Fertility – April 2013

Table 2 Top Sires with High Fertility – April 2013

Click on image for enlargement

Of course we all want to know what we will have to give up to get the female fertility. Further analysis of the twenty-four bulls listed in Table 2 shows that only significant concession would be in ‘show type’ for eight of the twelve top proven sires.  All bulls on this listing have above average indexes for PTAT or CONF.

The Bullvine Bottom Line

Half a century of breeding for increased yields, taller and more angularity cows have taken their toll on the fertility in our herds. Female fertility indexes are available for both males and females. With genomics these indexes became much more accurate. Now is the time to put the genetics for female fertility back into our modern Holsteins. It is not a “Perhaps or Maybe”, it is a “MUST”!


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