In partnership with Bovine Veterinarian
THURSDAY, OCT. 29, 2009 | VOL. 3, ISSUE 5

2009 DCRC
REGIONAL MEETINGS
It's not too late to register for the 2009 Regional Meetings. Learn more.
In this issue:
WHAT'S NEW IN REPRODUCTION
DCRC
Get a leg up on reproduction
 Lameness is one of the largest health problems on United States dairies, costing producers thousands of dollars annually in higher costs and culling rates, as well as reduced milk production. Another area sore feet negatively impacts is reproductive function, and research continues to show that lameness and breeding pen performance are closely related. Click here to read more.

Advancing dairy reproduction: the 2009 DCRC Reproduction Awards
In 2009 the DCRC created a Reproduction Awards program to recognize and honor dairy producers from across the United States who have successfully implemented management procedures to achieve high reproductive efficiency. Meet the four Platinum winners of the inaugural honors and learn more about how they make their reproductive program so successful. Access the full article.

DCRC RESEARCH SHORTS
Identify ketosis earlier by monitoring intake
 That's what a new study completed at the University of British Columbia reports in an article published in the October issue of the Journal of Dairy Science. In the study, feeding behaviors for 101 Holsteins were tracked three weeks before and three weeks after calving. Following calving, animals with subclinical ketosis were identified by monitoring β-hydroxybutyrate levels one week after calving. Researchers found cows with subclinical ketosis had lower dry matter intake, fewer visits to and less time spent at the feedbunk than healthy animals. These behaviors lead to the following conclusions:
  • For every 10-minute decline in time spent at the feedbunk the week before calving, the risk for subclinical ketosis increases by 1.9 times. A 2.2 pound drop in dry matter intake one week before calving increased the cow's chances of coming down with subclinical ketosis by 2.2 times.
  • The largest risk related to subclinical ketosis was associated with a 2.2 pound increase in the change in DMI one to two weeks before calving.
Researchers concluded that the time spent feeding, dry matter intake and behavior are important to maintain cow health and identify cows that may come down with a postpartum metabolic disorder.
    Click here to read more.

Detecting dystocia before calving
Cows experiencing calving difficulties are more likely to develop additional health problems in the upcoming lactation and can often be hard to get bred back. That's what makes identifying these cows early so critical.
    In a recent study completed at the University of British Columbia researchers monitored specific behaviors — dry matter intake, water intake, feeding and drinking time, meal size, standing time and number of transitions from standing to lying — to identify any potential relationships with calving difficulties. Each behavior was monitored two days before and two days after calving. Researchers found cows experiencing dystocia:
  • Consumed about 4.2 pounds less feed during the 48 hours before calving when compared to cows with no calving difficulties. Intake differences between the two groups jumped to 5.7 pounds in the 24 hours before calving.
  • While there was no significant difference, cows with dystocia drank less water 24 hours before calving and consumed more water in the 24 hours following calving.
  • Cows with dystocia transitioned from standing to lying positions more frequently — 10.9 per day — compared to the group without calving difficulties, which transitioned from one position to the next 8.3 times.
Researchers concluded that dry matter intake and standing bouts within the 24-hour period before calving were the most accurate variables in identifying cows with potential dystocia challenges. The study results also suggest cows with dystocia begin to alter their behavior 24 hours before calving.
    Read more by clicking here.

The influence of prostaglandin on endometritis and fertility
 A recent study from Cornell University analyzed the effect of PGF2α treatment on prevalence of subclinical ketosis and fertility. In the study, 406 cows from five farms were evaluated for ketosis status and body condition at 21, 35 and 49 days in milk. During these visits blood samples were also taken to evaluate estrous cyclicity.
    During each herd visit cows with even number ear tags received 25 milligrams of PGF2α and cows with odd number ear tags received a saline solution. The results were published in the September issue of the Journal of Dairy Science.
    Researchers concluded that cows with subclinical ketosis:
  • Took longer to get pregnant when diagnosed at 35 days in milk, but not when identified with ketosis at 21 days in milk. The median days to pregnancy were delayed 30 and 40 days for cows classified as having subclinical ketosis at days 35 and 49 days in milk, respectively. Treatment with PGF2α did not affect the prevalence of subclinical ketosis at days 35 and 49 or time to first artificial insemination.
  • PGF2α did improve conception rates in animals with poor body condition (< 2.5).
It was concluded that PGF2α did not influence subclinical ketosis or days to first service, but did improve conception rate and time to pregnancy in cows with low body condition scores.
    Learn more by clicking here.

PMN concentration linked to delayed ovarian function
 That's what new research from Iwate University in Japan recently reported in the September issue of Theriogenology. The study evaluated the uterine condition of 45 Holsteins from week three to week seven after calving. Researchers concluded the following:
  • By 49 days in milk, 78 percent of the cows had resumed ovarian function.
  • Percentage of polymorphonuclear leukocytes (PMN%) was higher in the 22 percent of noncycling cows than in the group that was cycling at five weeks postpartum.
  • The PMN% and vaginal mucus collection device (VMCD) scores at Week 5 postpartum were lower in cycling cows than those animals that were not ovulating by 49 days in milk.
Researchers concluded that higher PMN% five weeks after calving was associated with delayed resumption of ovarian cyclicity in high-producing dairy cows.
    Click here to learn more.

HIGHLIGHTS FROM DCRC 2008
Sire conception rate: a new fertility index
Dr. Duane Norman with the Animal Improvement Programs Laboratory of Agricultural Research Services, USDA, says artificial-insemination (A.I.) organizations and dairy farmers want reliable information relating to bull fertility. At the 2008 DCRC meetings, Dr. Norman outlined three fertility evaluations used in the dairy industry that can help producers gain critical information to help make the most accurate breeding decisions.

Estimated relative conception rate
Dairy Records Management Systems initiated estimated relative conception rate (ERCR) in 1986 as a fertility evaluation for service sires. ERCR evaluations included information on first-service inseminations from the three previous years. Those phenotypic evaluations were based on a 70-day nonreturn rate (NRR) to first service as reported in breeding records supplied by Dairy Herd Improvement (DHI) and bulls across A.I. organizations. Computerized DHI data made calculating an NRR convenient because data were readily accessible and updated continuously.

Western bull fertility analysis
In 2003 AgriTech Analytics introduced the Western Bull Fertility Analysis (WBFA), based primarily upon on-farm computer data from a few large herds in the western United States. WBFA is based on 75-day veterinary-confirmed conception rate (CR) using available pregnancy-check codes rather than NRR, and includes data for up to five services per cow per lactation. The entire breeding history for each bull is included in his WBFA evaluation; his breeding success is not restricted to the most recent years and, therefore, may not reflect recent changes in semen quality that ERCR accounts for.

Sire conception rate
In 2006, USDA's Animal Improvement Programs Laboratory (AIPL) assumed the responsibility for developing methods of evaluating bull fertility. Research by Dr. Melvin Kuhn led to the development of sire conception rate (SCR), which was implemented in 2008 and replaced ERCR. The SCR gives the probability that a specific bull's semen will result in a pregnancy when compared with other bulls that could have been used. SCR evaluation is based on confirmed pregnancies and measures phenotypic service-sire fertility. It is expressed as a relative CR (an average bull has an SCR of 0.0 percent). The standard deviation of SCR evaluations was 2.37 percent in August 2008.
    The first official SCR evaluations were released by USDA in August 2008 for active A.I. and progeny-test bulls that met a minimum number of inseminations (300 for Holsteins). Data from over 80 percent of the DHIA herds that collect breeding information are eligible for inclusion in the evaluation, and most states and Puerto Rico are represented for the six dairy breeds. Information from a larger number of inseminations is a primary reason for the higher accuracy of SCR compared with ERCR. Not only are more DHI herds included because many herds were added from the western U.S., but the second through seventh services were included as well. This alone tripled the amount of data available.
    Access the 2008 DCRC meeting proceedings.

Customer Service Menu — Contact Us

Subscribe

Or mail to: DCRC, 515 W. North Shore Drive, Hartland, WI 53029
© 2009 Dairy Cattle Reproduction Council. All rights reserved.