The  Physiology  of  Stock-Breeding. 
73 
process  is  interpreted  as  an  indication  that  the  follicles  and 
consequently  the  contained  ova  were  not  receiving  a sufficient 
supply  of  the  right  kind  of  nourishment.  As  the  follicle  in 
the  ovary  has  been  developing  for  some  time  previously  to 
the  rams  being  “ turned  in,”  and  as  it  is  apt  to  be  interfered 
with  by  want  of  proper  feeding,  a warning  may  here  be  taken 
by  those  who  do  not  keep  their  ewes  sufficiently  well  ’twixt 
“weaning”  and  “ tupping-time.”  This  period  is  always 
looked  upon  as  a cheap-keep  time  for  the  flock,  and  some 
shepherds  go  as  far  as  to  say  that  it  is  essential  to  thoroughly 
“ starve  the  milk  out  of  them  ” before  “ springing  ” or 
“ flushing  ” the  ewes  ready  for  ram  service.  Hence  it  may 
with  advantage  be  pointed  out  that  knowledge  of  the  physi- 
ology of  reproduction  teaches  that  this  cheap-keep  time  may 
be  overdone.  While  it  is  eminently  desirable  that  the  ewes 
should  not  get  too  fat,  it  can  be  seen  they  should  be  fed 
well  enough  to  nourish  the  developing  follicles.  In  very 
fat  animals  (cows  and  heifers)  I have  found  follicles  of  con- 
siderable size  in  a condition  of  degeneration,  and  in  such 
cases  their  occurrence  is  very  possibly  to  be  correlated  with  the 
sterility,  either  partial  or  complete,  which  is  known  so  often  to 
affect  stock  that  have  been  fattened.  However  this  may  be,  it 
is  obvious  that  if  a sufficiently  large  number  of  follicles  and 
ova  have  undergone  degeneration,  and  at  whatever  stage  in  their 
development  this  process  may  have  taken  place,  it  must  inevi- 
tably result  in  a reduction  of  fertility.  That  an  insufficiency 
of  the  right  kind  of  food  supply  or  a state  of  disease  should 
produce  a disturbance  in  the  ovarian  metabolism^  is  only  to  be 
expected  on  physiological  grounds,  but  that  a similar  result 
should  be  brought  about  by  a rich  fattening  diet  is  at  first  sight 
not  obvious.  It  is  well  known,  however,  to  all  those  who  have 
studied  the  subject  that  the  generative  organs  are  peculiarly 
susceptible  to  altered  conditions  of  existence,  not  only  as  regards 
food  supply,  but  also  as  regards  the  surroundings  generally,  and 
that  a change  in  the  environment  may  often  induce  a condition 
of  sterility. 
Breeders  are  generally  agreed  that  sheep  which  are  in  an 
improving  condition  rather  than  a condition  of  fat  at  tupping 
time  are  likely  to  produce  a good  crop  of  lambs,  and  that  certain 
stimulating  foods  fed  for  a few  weeks  before  breeding  but 
afterwards  discontinued  have  a favourable  effect  upon  the 
fertility.  In  the  case  of  Scottish  sheep  the  truth  of  this  asser- 
tion has  been  definitely  proved  by  statistics.^  Moreover,  it  is 
^ The  changes  undergone  by  the  living  tissues  of  the  body  are  grouped 
together  under  the  term  “ metabolism.” 
* Marshall  : “Fertility  in  Scottish  Sheep,”  Trans.  Highland  and  Agri. 
Soc.,  Vol.  20,  1908. 
