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0607 PD: Improved pregnancy rates boost profitability

Elliot Block Published on 06 June 2007

Ask 10 dairy producers their definition of a profitable cow and they’ll likely give you 10 different answers. From a reproductive standpoint, profitable cows are cows that calve in healthy, get bred back in 80 to 120 days in one or two services and stay healthy throughout lactation so they can dry off and repeat the process.

Getting cows bred back quickly after calving has a dramatic impact on profitability. More pregnant cows means you have a greater choice over which cows to cull, eliminating cows before they become problems and resulting in a healthier, more productive herd. More pregnancies will result in more calves, which means more heifer calves to keep as replacements, with extras to sell as breeding stock.

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Several research studies in large-herd settings show there is a direct correlation between improving pregnancy rates and enhancing profitability. Adding Omega-3 and Omega-6 essential fatty acids (EFAs) to a cow’s ration has been shown to raise pregnancy rates by up to 5 percentage points, when supplemented from the beginning of the close-up period through conception.

The link between higher pregnancy rates and added profits is well-documented and dramatic. Each percentage point increase in pregnancy rate equates to an additional $35 in profit. The gross profit per cow for the 3 percent increase in pregnancy rates is $105. If a product cost for the EFA supplement added to the ration is $6.25 per cow per percent, the net profit is $86.25 per cow, per year, or $86,250 in a 1,000-cow herd.

Cows cannot naturally produce Omega-3 and Omega-6, though they are vital for reproductive success. These EFAs can be found in other feedstuffs, such as roasted soybeans, whole cottonseed and flaxseed, but they are altered in the rumen before they can be absorbed. Rumen bypass fats, such as calcium salts of fatty acids, containing the right balance of Omega-3 and Omega-6 EFAs deliver these nutrients to the small intestine where they can be absorbed without impacting rumen microbes, feed intake, milk production or components.

Omega-3 and Omega-6 are the only EFAs proven to improve reproductive performance. Omega-3 aids in the production of prostaglandins, fosters embryonic survival and balances the function of Omega-6. Omega-6 aids in the production of prostaglandins, promotes ovulation and sperm capacitation, aids in oviduct contraction and maintains embryo implantation.

Omega-3 and Omega-6 EFAs in combination are crucial to reproductive function in cows. They have three key functions:

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• Aid in the production of specific reproductive hormones (progesterone). Higher concentrations result in stronger heat signs, improving heat detection, higher conception rates and maintaining pregnancies.

• Aid in the production of eicosanoids (prostaglandins). These cause ovulation and a subsequent estrous cycle. In addition, they enhance visible signs of heat and increase blood flow to the ovaries to promote follicle growth.

• Promote cell wall integrity.

Dr. Roy Ax, professor of reproductive physiology, and Bonnie Jones, a master of science degree recipient at the University of Arizona, recently conducted a trial on a 2,000-cow commercial dairy with a rolling herd average of 21,000 pounds of milk. The objective of this study was to determine how the Omega-3 and Omega-6 EFAs improve reproductive performance.

All cows were fed 0.35 pounds of rumen bypass fat for three weeks pre-calving. From calving to 150 days in milk (DIM) cows were fed 0.35 pounds of either rumen bypass fat or rumen bypass fat containing extra Omega-3 and Omega-6 EFAs. Rations were balanced for equal energy. The following measurements were taken:

• Ultrasounds to evaluate ovarian structures (120 cows)

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• Milk progesterone levels

• Uterine health based on veterinarian prescription of prostaglandins

• Conception rate differences between treatments

Cows were synchronized on the Ovsynch™ program at the same time postpartum to remove any effects of heat detection.

At the first 30 days, cows on Omega-3 and Omega-6 EFAs had nearly twice as many ovulations, 49 percent versus 27 percent, Ax explains. Cows gained almost an entire additional cycle, as evidenced by the trial results. The ultrasound results are shown in Table 1*.

Research done in the A.I. industry, Ax says, has shown the more ovulations a cow has after calving, the higher her fertility will be on a first A.I. service. In the trial, cows fed the extra Omega-3 and Omega-6 EFAs had 2.7 cycles versus 2.0 cycles for cows fed only rumen bypass fat. The researchers also compiled data on the number of cows treated with prostaglandins for uterine health issues by the herd veterinarian in trial groups. The therapy included treatment for metritis, poor uterine tone, clean-out and cystic ovaries.

Results showed 25 percent fewer cows were treated by 60 days in milk in the group fed the rumen bypass fat containing Omega-3 and Omega-6 EFAs. The difference was significant, Ax explains, as was the amount of money saved by not treating cows with prostaglandins. Producers save money by reducing medication cost, using less labor and improving fertility. Data are shown in Table 2*.

Cows fed Omega-3 and Omega-6 EFAs experience health benefits beyond more successful reproduction. A foundation study of four trials analyzed more than 4,200 cows averaging over 27,000 pounds of 305 ME milk. The cows were fed varying levels of the nutritional supplement from pre-fresh through the voluntary waiting period for breeding. Results showed cumulative pregnancies increased up to 19.1 percent as compared to cows fed a rumen bypass fat product. Cows fed the supplement also had fewer post-calving disorders, DAs, milk fevers and abortions.

Ax recommends this “to-do list” to optimize the reproductive program in your herd and improve pregnancy rates:

1. Provide a clean, dry area for cows to calve.

2. Supervise each calving and know when to call on professionals. Avoid assisting the cow with every calving.

3. Fine-tune dry cow management. Preparing a cow for her next lactation starts well before calving and includes proper rations and supplements. Work with your nutritionist.

4. Do all you can to stimulate appetites of cows during the transition period.

5. Don’t overlook fresh, clean water available to cows at calving.

6. Consider using a breeding synchronization program as an option to get cows rebred quickly after calving. PD

*Tables and references omitted but are available upon request at .

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