Source: UNIVERSITY OF WYOMING submitted to
THE EFFECT OF HOLDING TIME ON RAM SEMEN FERTILITY
Sponsoring Institution
Agricultural Research Service/USDA
Project Status
TERMINATED
Funding Source
USDA COOPERATIVE AGREEMENT
Reporting Frequency
Annual
Accession No.
0408481
Grant No.
(N/A)
Project No.
5402-31000-004-04S
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Sep 27, 2004
Project End Date
May 1, 2009
Grant Year
(N/A)
Project Director
BLACKBURN H D
Recipient Organization
UNIVERSITY OF WYOMING
1000 E UNIVERSITY AVE DEPARTMENT 3434
LARAMIE,WY 82071-2000
Performing Department
ANIMAL SCIENCE
Non Technical Summary
(N/A)
Animal Health Component
(N/A)
Research Effort Categories
Basic
30%
Applied
20%
Developmental
50%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
30436101080100%
Knowledge Area
304 - Animal Genome;

Subject Of Investigation
3610 - Sheep, live animal;

Field Of Science
1080 - Genetics;
Goals / Objectives
ARS and the Cooperator (University of Wyoming, Department of Animal Science, UW) desire to enter into this Cooperative Agreement for the purpose of determining the fertilizing capacity of ram semen frozen after a 24-hour holding period. Such an effort is consistent with the goals of the National Animal Germplasm Program (NAGP) and the UW. Making such an assessment is a critical step in determining how well ram semen that is collected at distant locations will hold while being shipped to the NAGP laboratory in Fort Collins.
Project Methods
Semen will be collected from three UW rams and frozen at the time of collection (0 hour) and 24 hours after collection. Estrus will be synchronized on 140 western whiteface ewes. Upon synchronization of estrus the ewes will be artificially inseminated with freshly collected semen or semen frozen at the time of collection (0 hour or 24 hours after collection). Results will be derived from the number of pregnancies and live lambs born per ewe bred.

Progress 10/01/08 to 09/30/09

Outputs
Progress Report Objectives (from AD-416) ARS and the Cooperator (University of Wyoming, Department of Animal Science, UW) desire to enter into this Cooperative Agreement for the purpose of determining the fertilizing capacity of ram semen frozen after a 24-hour holding period. Such an effort is consistent with the goals of the National Animal Germplasm Program (NAGP) and the UW. Making such an assessment is a critical step in determining how well ram semen that is collected at distant locations will hold while being shipped to the NAGP laboratory in Fort Collins. Approach (from AD-416) Semen will be collected from three UW rams and frozen at the time of collection (0 hour) and 24 hours after collection. Estrus will be synchronized on 140 western whiteface ewes. Upon synchronization of estrus the ewes will be artificially inseminated with freshly collected semen or semen frozen at the time of collection (0 hour or 24 hours after collection). Results will be derived from the number of pregnancies and live lambs born per ewe bred. Significant Activities that Support Special Target Populations This cooperative research between members of the Department of Animal Science of the University of Wyoming and the NAGP began in the fall of 2003 with an investigation into the ability to hold ram semen at 5 �C for up to 48 hours prior to cryopreservation. Post-thaw analysis of these samples demonstrated that the holding time was not detrimental to sperm quality (motility and membrane quality). Furthermore, the holding time prior to freezing was not detrimental to fertility or prolificacy (number of lambs born per ewe lambing) when surgical artificial inseminations were performed. This therefore enabled us to confidently collect ram semen samples for the repository from around the U.S. knowing that the material would be acceptable for use in the future after storage. Our research of artificial insemination continued as we investigated a non- surgical method, to artificially inseminate sheep. We demonstrated that the method does work but improvements in estrous synchronization methods are needed to increase fertility. Even so, the method holds promise because it is simpler and more cost effective in comparison to the surgical method of artificial insemination. This project was monitored by frequent calls with the collaborators and site visits to the University of Wyoming.

Impacts
(N/A)

Publications


    Progress 09/27/04 to 05/01/09

    Outputs
    Progress Report Objectives (from AD-416) ARS and the Cooperator (University of Wyoming, Department of Animal Science, UW) desire to enter into this Cooperative Agreement for the purpose of determining the fertilizing capacity of ram semen frozen after a 24-hour holding period. Such an effort is consistent with the goals of the National Animal Germplasm Program (NAGP) and the UW. Making such an assessment is a critical step in determining how well ram semen that is collected at distant locations will hold while being shipped to the NAGP laboratory in Fort Collins. Approach (from AD-416) Semen will be collected from three UW rams and frozen at the time of collection (0 hour) and 24 hours after collection. Estrus will be synchronized on 140 western whiteface ewes. Upon synchronization of estrus the ewes will be artificially inseminated with freshly collected semen or semen frozen at the time of collection (0 hour or 24 hours after collection). Results will be derived from the number of pregnancies and live lambs born per ewe bred. Significant Activities that Support Special Target Populations Artificially inseminating (AI) sheep can be accomplished using either surgical or non-surgical techniques. The non-surgical techniques are not consistently successful due to the inability to traverse the cervix of the ewe. The surgical techniques for sheep AI are successful, generally greater than 60% fertility, but the costs associated with hiring a trained technician and/or purchasing the equipment can be prohibitive for researchers or producers. At the National Animal Germplasm Program (NAGP) , we bank frozen semen that has been held for up to 48 hours prior to freezing, but must also be able to use the material for creating live animals. Therefore, our past research has investigated an alternative method to AI sheep in a fast economical manner using the semen and the semen cryopreservation methodologies we are developing. In the first year of the investigation of the new technique we inseminated 100 ewes; 50 with fresh semen and 50 with frozen-thawed semen (24 hours old at the time of cryopreservation). We were able to get one ewe, which was inseminated with fresh semen, pregnant. Still, we learned that the technique could work, but it needed to be improved. Consequently, our technique was refined and in our second year 47% of ewes inseminated with fresh semen lambed and 10% of the ewes inseminated with frozen semen (24 hours old at the time of cryopreservation) lambed. This documents that the AI technique has been improved but is still in need of fine-tuning so that the resulting fertility is increased. We now believe the key to increasing the fertility with this technique, and with semen that has been held prior to freezing, is dependent upon proper timing of insemination. For that reason, future research will investigate alternative methods of ewe estrous cycle synchronization. ADODR monitoring of project progress included regular trips to Laramie, personal meetings, phone contact and email.

    Impacts
    (N/A)

    Publications


      Progress 10/01/06 to 09/30/07

      Outputs
      Progress Report Objectives (from AD-416) ARS and the Cooperator (University of Wyoming, Department of Animal Science, UW) desire to enter into this Cooperative Agreement for the purpose of determining the fertilizing capacity of ram semen frozen after a 24-hour holding period. Such an effort is consistent with the goals of the National Animal Germplasm Program (NAGP) and the UW. Making such an assessment is a critical step in determining how well ram semen that is collected at distant locations will hold while being shipped to the NAGP laboratory in Fort Collins. Approach (from AD-416) Semen will be collected from three UW rams and frozen at the time of collection (0 hour) and 24 hours after collection. Estrus will be synchronized on 140 western whiteface ewes. Upon synchronization of estrus the ewes will be artificially inseminated with freshly collected semen or semen frozen at the time of collection (0 hour or 24 hours after collection). Results will be derived from the number of pregnancies and live lambs born per ewe bred. Significant Activities that Support Special Target Populations This report serves to document research conducted under the specific cooperative agreement between ARS and the University of Wyoming. Additional details of research can be found in the report for the parent project 5402-31000-001-00D, National Animal Germplasm Program. Under this project we have demonstrated that ram semen can be held for 24 hours prior to cryopreservation, this facilitates our collection efforts. However, inefficiency exists in how ewes are artificially bred. The objective of this effort was to improve the method of artificial insemination used for sheep with semen that had been subjected to a 24 holding period prior to cryopreservation. The trans-cervical method evaluated was designed to be low cost, rapid, and simply performed by a technician with minimum thus avoiding the surgical inseminations normally used in the industry which are expensive and time consuming. First fertility results were low for this methodology of insemination but important knowledge concerning sheep artificial insemination was learned. We confirmed our estrous synchronization protocol was operational and effective; and morphological and physiological knowledge of the structure of the ewe�s cervix (perhaps the greatest barrier to artificial insemination in sheep) was gained. This knowledge has enabled us to retool our insemination technique so that another trial can be performed this year. Even though the fertility was low, this demonstrates that fertility is achievable but needs modification to develop this technique that has direct application to producers and the scientific community. Project progress is monitored by regular face to face meetings, phone contact and email.

      Impacts
      (N/A)

      Publications


        Progress 10/01/05 to 09/30/06

        Outputs
        Progress Report 4d Progress report. This report documents research conducted under the specific cooperative agreement between ARS and the University of Wyoming, Animal Science Department. Additional details of research can be found in the report for the parent project 5402-31000-001-00D, National Animal Germplasm Program (NAGP). The objective of this effort was to determine if there were differences in ewe fertility when artificially inseminated with fresh semen, semen cryopreserved after a 24 hour holding period, or semen cryopreserved after a 24 hour holding period with cholesterol added to the extender. For these three treatments the conception rates were 45, 38 and 40%, respectively. The treatment differences were not significantly different. This second year's data confirm that ram semen can be effectively held for 24 hours before cryopreservation with out sacrificing fertility levels. This is an important result for it supports the acquisition practice of collecting rams in different locations and shipping the semen to the NAGP lab for processing, furthermore it can facilitate the development of artificial insemination by the sheep industry.

        Impacts
        (N/A)

        Publications


          Progress 10/01/04 to 09/30/05

          Outputs
          4d Progress report. This report documents the specific cooperative agreement with the Animal Science Department at University of Wyoming. Additional details of research can be found in the parent ARS Project #5402-31000-002-00D titled National Animal Germplasm Program. The objective of this effort was to determine if there were differences in ewe fertility when artificially inseminated with fresh semen, semen cryopreserved immediately after collection, or semen cryopreserved after a 24 hour holding period. We found the semen treatment effect to be significant with average conception rates of 30.4%, 23.3%, and 21.4% for fresh, time 0 and time 24, respectively. While fresh semen was superior to cryopreserved treatments, there was no significant difference between the two cryopreservation treatments. This is an important result for it supports the acquisition practice of collecting rams in different locations and shipping the semen to the NAGP lab for processing.

          Impacts
          (N/A)

          Publications