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Dosing Bovine Semen by Progressively Motile Sperm: Impact on Pregnancy Rates in Dairy Cattle

Wednesday, May 12, 2010

Dosing Bovine Semen by Progressively Motile Sperm: Impact on Pregnancy Rates in Dairy Cattle


Y. Zeron1, L. Rabinovitch2, U.Shalit2, M. Deutsch2.

1Sion A.I. Company, Israel, 2Medical Electronic Systems, Caesarea, Israel.

The objective of this field trial was to evaluate the impact on pregnancy rates in dairy cattle inseminated with frozen semen that was dosed by progressively motile sperm per AI dose post thaw (PMPT).

The trial was divided into two phases. Phase 1 established a post thaw progressive motility loss factor (PMLF) per bull enrolled in the trial, tested the accuracy of preparing AI straws by # of progressively motile cells/straw post thaw, and provided the AI straws for the second phase.  Phase 2 analyzed the impact on pregnancy rates when inseminating large numbers of dairy cattle with the AI straws prepared in the first phase. In phase 1 of the trial, a unique PMLF was established for each of four Holstein bulls enrolled in the trial. The PMLF represents the overall percent decrease in the number of progressively motile cells resulting from the freezing/thawing process. Both fresh and post thaw frozen semen was tested using an automated sperm quality analyzer for bulls, the SQA-Vb. AI doses were all prepared using B-Sperm™ dosing software (Medical Electronic Systems, Ltd., Israel). Once the PMLF was established for each bull, 10 ejaculates from each of the four bulls were collected and tested using the automated SQA-Vb. Each ejaculate was split into four aliquots and used to prepare four AI dose batches (A, B, C, D) following the B-Sperm™ dosing software instructions. Three aliquots (A, B, C) were dosed by the number of progressively motile sperm post thaw targeting 1.5, 3.5 and 7.0 million per dose respectively. One aliquot per ejaculate (D) was dosed by targeting 15.0 million total number of sperm/dose, representing the standard dose preparation procedure at the stud (SION AI Company, Israel) and served as the study control. Microsoft Excel™ was used for statistical evaluation of the trial results.

A complete semen analysis was performed on seventy-six post-thaw AI straws from each batch using the SQA-Vb to determine the actual PMPT. The mean values +/- SEM for PMPT by batch were: (A) 1.5 +/- 0.05; (B) 3.0 +/- 0.09 and (C) 6.2 +/- 0.18 million progressively motile spermatozoa per dose. The mean value +/- SEM for total sperm cells per AI dose in batch D (Control) was 13.6 +/- 0.15 million. These results were found to be acceptable and a total of approximately 8,000 AI doses (2,000 per group) were distributed into straws and frozen by the stud technicians (Sion AI Company, Israel). In the 2nd phase of the trial 6,494 Holstein cows residing in more than 500 farms were artificially inseminated with semen from batch A, B, C or D between January and April 2009. Manual palpation pregnancy testing was conducted by veterinarians at approximately 42 days post-insemination. The insemination procedure and the pregnancy testing were performed blindly.  Pregnancy rates (per cow per cycle) were found to be: (Group A Target: 1.5 M Progressively Motile Sperm/dose) 34.2%; (Group B Target 3.5 M Progressively Motile Sperm/dose) 39.3%; (Group C Target 7.0 Progressively Motile Sperm/dose) 43.2; (Group D Control Target 15.0 M Total Sperm/dose) 38.6%. Significant differences were found between groups A (1.5M Prog Mot) and D (15M Total), C (7.0M Prog Mot) and D (15M Total), A (1.5M Prog Mot) and C (7.0M Prog Mot). The relative differences in pregnancy rates in the experimental groups A, B and C vs. the control were: -11.4%, 1.8% and 11.9%, respectively. A high correlation between the pregnancy rates in groups A, B and C and the number of progressively motile spermatozoa per AI dose (r = 0.96) was found.

It can be concluded that it is possible to accurately produce AI straws of frozen bovine semen based on a targeted post thaw number of progressively motile sperm cells per dose in a commercial setting. It was also demonstrated that pregnancy rates highly correlate to the number of progressively motile sperm cells per AI dose as demonstrated by a favorable 11.9% increase in pregnancy rates using AI straws from the highest PMPT group (C=7.0M Prog Mot) vs. the control, and in contrast, a 11.4% decrease in pregnancy rates using AI straws from the lowest PMPT group (A=1.5M Prog Mot) vs. the control. 

Key words: Progressive motility; Pregnancy rate; SQA-Vb; Frozen bovine semen; B-Sperm

Day in the life of a Dairy Cow Inseminator: Israel Dairy Co-op

Saturday, January 16, 2010
Israel is known to be one of the most successful milk producing nations in the world with exemplary milk production per cow. There are over 500 dairy farms in Israel that belong to a national dairy co-op known as the Cattle Confederation. The Cattle Confederation maintains a centralized herd book that tracks and reports the genetics and health and milk production/quality for over 100,000 dairy cattle. Under the umbrella of the Cattle Confederation is the Haklaite, an organization of veterinarians providing health related services to the cattle industry and SION AI Stud which produces the AI straws used to inseminate the dairy cattle (with the assistance of the SQA-Vb and B-Sperm™ dosing software). A-TECH was invited to follow “Dr. Alex” of Sion AI Stud on his insemination rounds in December 2009. Of interest to A-Tech was the process of tracking the cow, determining whether she was “in-heat,” selecting AI samples and observing how the AI straws are handled in field conditions. A-Tech wanted to observe the full cycle of milk production in Israel at a cross-section of farms with as few as 200 cows and as many as 1200. “Dr. Alex” has been working for the dairy co-op (SION AI stud) for over 30 years. On his day with A-Tech he visited 14 farms.

Here are some pictures and description of the process:

A graph is viewed to determine if a cow is ready for insemination. A software program used by the co-op takes pedometer data and looks for increased activity as one indication that the cow in in-heat. The graph spikes can be viewed in this picture:

A record card and label are kept on file for every dairy cow. The card contains her statistics and genetic history. A bar-coded label is affixed to the form for easy identification and tracking:

A hand held PDA scans the bar-code label on the cow record card and the cow data is automatically transferred into the device:

“Dr. Alex” then enters relevant AI data by hand. The data base is checked electronically and a warning is displayed if the cow/bull are related and the insemination is not allowed:

A genetic chart of participating AI bulls and their genetic characteristics is reviewed in order to select the best AI straw for the cow. Milk production, leg strength, etc. are considered:

A small liquid nitrogen tank contains AI straws prepared at SION AI STUD using the SQA-Vb and B-Sperm dosing software. Straws are thawed and loaded into the insemination gun to prepare for the insemination procedure:

The insemination is performed by “Dr. Alex” on Bessie:

Cows taking a meal before insemination:

Almost ready for the milking parlor:

The QwikCheck™ Gold BULL Sperm Quality Analyzer goes to BSE beta testing

Tuesday, January 12, 2010

The QwikCheck™ Gold Bull has just hit the market after being used for BSE exams in the field. The beta testing was done “in field conditions” to determine how the QwikCheck™ would perform from the back of a truck or on a portable table at the bull collection pens. “Dr. Moti (DVM)” was engaged by A-TECH to test the system during his bi-annual bull soundness examination rounds. He used the system, label printer and testing capillaries after very little training and successfully performed his rounds over a couple of weeks in October-November, 2009.

Trailing water, you could mistake them for ducklings:

System in action, waiting for the next sample:

System, printer, supplies and mil-spec travel case - the complete package:

A fine animal taking in the morning sun:

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