[Jacob-list] Breeding out of season....

[Jacobflock at aol.com]

In a message dated 4/18/2004 8:06:29 PM Central Standard Time, 
karen at benjaminfarms.com writes:

>   Jacobs are one of the few breeds that do breed out of season, thus 
> allowing for two crops of lambs (and very tired ewes) in one year.   
> 

This and other statements depend on several premises flowing from an 
understanding of sheep (reproduction), the Jacob as a breed (what seperates it from 
other breeds), its history, flock management and personal flock objectives (a 
continuum from conservation to pets).

I do not want to make this more than a reflective issue but what if the 
statement was framed in terms of a conclusion to a question that might be tested 
against scientific method?  Are Jacobs one of the few breeds that do breed out 
of season and produce two crops of lambs (and very tired ewes) in one year?  It 
can be thought provoking and may provide insight into the breed and breed 
conservation practices.

ARE: (an interogatory of the present tense) the Jacob.  Does this exclude the 
alternative of WAS the Jacob (historic, past tense) and WILL the Jacob 
(furture tense) ....  The sense of tense can help identify past and potential breed 
changes.

JACOBS: might be unimproved or improved which goes to genotype and management 
and a descriptive (what it is) or prescriptive (what the ideal should be) 
phenotype definition of the breed and why it is a breed ... landrace type or 
standardized.  It is not my intent to retrace Homer's voyage between Scylla and 
Charybdis but to suggest it is on the map.

ONE OF THE FEW BREEDS: (what is a breed, and how many of the 400 breeds of 
sheep or 50 breeds (World/US respectively) should be considered)

THAT DO BREED OUT OF SEASON:  why, how and when does a sheep breed? How does 
a natural population reproduce and survive (behavior and process) and how do 
we manage (or not manage) domestic livestock breeding?  Is "do breed out of 
season" the result of a gene, a result of positive/associative breeding selection 
for a traait, or does this mean "can be bred" as a manipulated activity?  
What is a season and not a season and how to account for light and temperature 
(ewe melatonin and ram motility)?  Should season include a post-partum estrus 
cycle for both unmanageged natural populations and managed domestic breeds?  

THUS TWO CROPS OF LAMBS (AND VERY TIRED EWES) IN ONE YEAR:  Does the term 
"crop" have an economic nuance and "very tired ewes" describe its phenotype?   

The intersection of opinion and fact is congested.   But based on my 
understanding of the species and breed, I don't thnk that the Jacob is one of few 
breeds that breed out of season ... but phenotype is the result of genotype and 
management.  

We have three groups of 24 rams running loose in a field surrounding one 
group of 40 ewes and another group of 20 ewes with 4 other rams available. I have 
not observed a ewe "on the ready" nor a ram displaying the flehman associated 
with estrus (i.e., an apparent quick scent test but not the protracted curl 
with Fall hormones).  While they are all loose in abutting fields, their social 
behavior seems to suggest that observed by Geist and their breeding behavior 
as stated by Ryder.  This behavior is not prescriptive of the Jacob breed but 
descriptive of one little group.

Fred Horak
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