Fall Lambing Problem

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Fall Lambing Problem By Clayton Wohlk, Lydia
Hardie, Tracy Hansen, and Jason Blankenheim
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Scenario

• You have been asked to consult with a 4-H member
  from Wisconsin.
• He has a small flock of purebred Suffolk sheep
  which he would like to breed for fall lambing so
  that the ram lambs will be worth more.
• He can pay his younger siblings to take care of
  the lambing during the week but will be there on
  weekends.
• He is a bright individual and finds information
  on using the Easi-Breed sheep insert along with
  PG600.

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Fall Lambing

• Sheep are usually fall breeders and spring
  lambers. We are trying to reverse this.
• They usually breed in October or November, and
  lamb in March or April.
• We want to breed in May and Lamb in October.
• We will be using CIDRs to start their estrous
  cycle about a month after their lambing in the
  spring.

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Schedule

• Following Lambing in March or April, Ewes will be
  housed separate from any visual or scent contact
  with the rams.
• May 1- Introduce Teaser Ram to induce a silent
  ovulation on May 3rd or 4th.
• May 12- Insert CIDR
• May 18- (6 days after inserting CIDR) administer
  a prostaglandin
• May 19- Remove CIDR and introduce Breeding Rams
• May 21- Expect to see estrus behavior and
  breeding
• June 7- (Approximately 17 days after 1st estrus)
  Expect to see a second estrus on ewes that did
  not become pregnant the first cycle.

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Drugs and Responses
CIDR (www.ansci.wisc.edu)
Prostaglandin (www.vetmed.lsu.edu)
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Within the species you are working with, how does
the reproductive state of the animal affect the
ability of the treatment to work? Are there
reproductive states for which the treatment will
not work?

• Seasonal cycling limits treatments available
• Prostaglandins cannot be used in non-cycling ewes
  as there is not a corpus luteum present to
  regress.
• Dont treat any ewes that happen to still be
  pregnant as they will lose any lambs they are
  carrying.
• Progesterone-based and melatonin treatments are
  effective in inducing estrus in non-cycling ewes.

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How do you suggest the client determine if the
treatment regime works?

• Conduct an experiment by dividing the 20 ewes
  into two separate random groups.
• All with the same management.
• Experiment done in late spring/early summer
• Control group will be exposed to only a teaser
  ram.
• Test group will go through treatment regime of a
  CIDR and Prostaglandin.
• Watch readily for heat for a month (since ewes
  come into heat at day 17 for 36-40 hours.)
• Base the results of the experiment on the number
  of ewes that come into estrous and are ready to
  be bred.
• The success of the treatment regime will be
  concluded by a higher prevalence of estrous
  compared to the control group.

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What specifically will you recommend to the
client about labor needs to implement the cycle
management and manage parturition?

• The reproductive protocol is fairly standard,
  easy to follow, and extremely simple.
• I would recommend to the client that one person
  be responsible for inserting the CIDRs, removing
  the CIDRs, and administering the prostaglandin
  shot to keep the program consistent and thorough.
  
• At the time of parturition having one or two
  people on hand would be useful, but between the
  client and his brother they should not have to
  many problem since lambing in the fall is
  pleasant due to favorable weather conditions,
  fewer problems with parasites, and fewer problems
  with coyote predation.

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References

• http//www.sheep101.info/201/ewerepro.html