550 
Diseases  of  Cattle  and  Sheep. 
necessary  warmth,  food,  and  air,  on  which  the  body  depends  for 
healthy  development,  are  desirable  objects  to  be  obtained  in  the 
rearing’  of  cattle,  even  on  the  score  of  economy.  I have  not  been 
advocating  a forcing  system,  but  simply  recommending  such  food, 
from  call  hood  to  the  termination  of  growth,  as  shall  insure  health 
and  strength  and  immunity  from  disease. 
The  period  of  the  termination  of  growth — that  is,  of  muscle  or 
flesh — depends  on  the  character  of  the  breeds.  The  Short-horns, 
Herefords,  and  improved  Devon  cattle,  and  the  improved  long- 
wool  sheep,  such  as  Leicesters  and  Cotswolds,  arrive  at  maturity 
a year  sooner  than  those  of  most  other  varieties.  From  this  period 
the  nutrition  of  the  muscular  tissues  ceases  to  a degree,  and  fat  or 
milk  is  readily  secreted. 
We  have  seen  that  during  the  early  periods  of  life  the  vital 
principles  of  both  cattle  and  sheep  are  considerably  taxed  by  re- 
sistance required  to  be  made  against  cold,  wet,  and  insufficient 
food  ; and  predisposition  to  many  diseases  is  formed  from  these 
debilitating  influences  in  consequence.  Thus  tubercles  are  fre- 
quently formed  in  hog  sheep  and  young  cattle;  but  the  majority 
being  slaughtered  for  food  before  any  constitutional  disturbances 
take  place,  their  effect  is  not  often  observed. 
These  abnormal  deposits  are  the  cause  of  consumption  in  cows. 
The  organic  materials  of  the  body  are  more  or  less  prone  to  decay, 
becoming  effete  or  worn  out  in  a limited  period  of  time,  and  new 
ones  are  deposited  in  their  places.  But  this  renewal  must  depend 
on  the  supply  of  healthy  chyle  to  the  living  structures  ; and  if  it  be 
defective  in  quantity  or  quality,  mal  nutrition  takes  place,  and  the 
fibrin  of  the  blood,  instead  of  acting  as  a plastic  material  for 
renewing  the  worn-out  parts,  becomes  a source  of  tubercles,  and 
the  lungs  speedily  suffer,  and  that  often  to  a considerable  extent. 
They  are  also  formed  under  certain  pathological  states,  the  con- 
sequence of  exposure  to  cold  and  wet,  such  as  congestions  and 
chronic  inflammations. 
I find  that  hog  sheep,  bred  and  reared  on  sheltered  farms, 
and  fairly  fed,  seldom  exhibit  tubercles  on  the  lungs  on  being 
slaughtered,  whilst  portions  of  the  same  flocks,  reared  on  cold 
exposed  places,  are  rarely  slaughtered  without  them — studding  the 
lungs  as  it  were  in  every  direction.  On  the  hilly  granite  districts 
of  Devon  and  Cornwall  the  farmers  do  not  breed  their  sheep,  but 
purchase  ewes  in  lamb  at  the  autumnal  sheep  lairs,  of  flockmasters 
residing  on  good  sheltered  arable  land.  The  ewes  and  their 
progeny  are  sold  fat  the  following  year,  and  new  stock  purchased 
to  replace  them.  These  invariably  exhibit  tubercles,  whilst  the 
parent  stock,  as  before  stated,  are  free  from  the  disease. 
Chronic  diarrhoea  is  another  disease  common  to  milch  cows 
that  have  been  improperly  managed  in  early  life.  It  is  never 
