Ohio BEEF Cattle Letter

– B. Richardson, S. Hill, J. Stevenson, G. Djira, and G. Perry (summarized by Steve Boyles, OSU Extension Beef Specialist)

Expression of estrus after Prostaglandin administration and before fixed-time AI has been reported to change the uterine environment, increase accessory sperm numbers, fertilization rates, and overall embryo survival. Thus, expression of estrus can strongly impact overall pregnancy success. Because of variation in percentage of beef females detected in estrus and number of animals per study, it can be difficult to detect a significant effect of estrus on pregnancy success. Thus, a meta-analysis was conducted using data from 10,116 beef females in 22 studies that utilized variations of the 5 most common fixed-time AI protocols (CO-Synch, 7-day CO-Synch + CIDR, 5-day CIDR, PG 6-day CIDR, and the 14-day CIDR protocols) to examine the effect of detection in standing estrus on subsequent fixed-time AI pregnancy success.

Overall there was a positive effect of estrus on conception rates with Continue reading →

– Kris Ringwall, Beef Specialist, NDSU Extension

Are the cows ready to breed, and will 60 percent conceive a calf within 21 days following bull turnout?

In reality, cattle never should be out of shape for breeding. Weather and feed supplies always should be managed so animals are in good condition. The important point, however, is to know where the cattle operation is at, avoiding unforeseen disappointments next fall.

Let’s talk about cows. Typical 1,300-pound cows consume 25 to 30-plus pounds of dry matter a day, depending on the stage of pregnancy and milk production. Dry, pregnant cows will be at the lower end of total feed needs. Lactating cows may very well exceed the upper end.

Remember, as cows climb the body weight ladder, to 1,500 to 1,600 pounds, they are going to need Continue reading →

– John F. Grimes, OSU Extension Beef Coordinator

A few years ago, I wrote an article relating to shortening the breeding season titled “Utilize the K.I.S.S. Method!” The acronym used in the title of that article referred to my preference for the appropriate length of the beef cattle calving season and imminent breeding season. In this situation, K.I.S.S. refers to “Keep It Short and Sweet!” In this article, I want to remind you of the primary advantages of a shorter breeding season. I also want to discuss a potential marketing advantage of actually lengthening the breeding season.

There can be compelling arguments to make when choosing the best calving season for a particular operation. It is my experience that there is no single best choice for a calving season for all operations. Each operation is unique as to the assets available to devote to the cattle operation including labor, facilities, feedstuffs, etc. Ultimately, the selection of your particular calving season should be determined by Continue reading →

– Dr. Les Anderson, University of Kentucky

The easiest road to maximum breeding efficiency in the beef cow-calf industry is through estrous synchronization and AI (ESAI). Estrous synchronization helps shorten the calving season, increases herd pregnancy rates, and helps increase calf uniformity and weight (calves are typically older).

Use of ESAI can improve productivity and revenue. Recent research from Dr. Cliff Lamb examined the short-term economic impact of a breeding system that included FTAI + natural service or just natural service in about 1,200 females on 8 different farms (Table 1).[1] The breeding seasons began and ended on the same day in both groups on all farms. A partial budget was used to compare the positive economic impact (added revenue, reduced costs) with the negative Continue reading →

– Sandy Johnson, Extension Beef Specialist, Kansas State University

For an increasing number of producers, artificial insemination (AI) and estrus synchronization are tools that help them reach their production goals and allow them to take advantage of genetic choices only available through AI. Reduced risk of calving difficulty from use of high accuracy calving ease sires on replacement heifers is a great advantage to AI users.

Fixed-time AI protocols have allowed producers to eliminate the time and expense of heat detection and still achieve industry-acceptable pregnancy rates to AI. However, information about estrous status at AI may allow producers to target expenditures for AI more effectively. While this may seem hard to understand coming from someone who has spent years talking about fixed-time AI, let me share some research that will explain further.

First, a low cost, accurate method of heat detection is now available in the form of Continue reading →

– Joseph C. Dalton, Ph.D., Professor, University of Idaho

One of the most frequent questions about AI technique focuses on the site of semen deposition, specifically, whether uterine horn breeding results in greater fertility than traditional uterine body breeding.

First, a quick review of anatomy. The cow and heifer reproductive tract includes the vagina, cervix, uterine body, two uterine horns, two oviducts and two ovaries. Following ovulation, the ovum (egg) moves down the oviduct to the site of fertilization, the ampullary-isthmic junction (AIJ). The AIJ is where the ampulla (upper portion) of the oviduct transitions into the isthmus (lower portion) of the oviduct. Following fertilization, the embryo enters the uterus a few days later.

The thought process is horn breeding, in which semen is deposited in each uterine horn during AI, should result in Continue reading →