Aprit 15, 1906 
rode, 
Diseases of Farm 
~inimals. 
'§. S. Camuron, M.R.C.V.S. 
Climate. 
‘The climate and meteorological conditions 
prevailing, not only in different countries, but 
also during different seasons of the year in the 
game country, are well known to have an effect 
on the liability of both animals and man to 
disease; and this, apart from the much-experi- 
enced effect of change of climate (i.e., removal 
to a different climate), which, in many cases, 
may be considered as on exciting cause rather 
than a predisposing one. The widely held notion 
that the blood becomes thinner after continued 
sojourn in a hot climate, and is thicker in cold 
countries is erroneous. That the circulation of 
the blood may be more sluggish in cold countries 
than in hot, where the temperature influences. 
function-energies, may be admitted ; but that 
the blood itself is altered in composition, con- 
sistence, specific gravity, or fluidity, cannot be 
scientifically contended. io ; 
The circumstances which determine the in- 
flu-:nce of climate on causation of disease are 
not well understood, but in recent years fight 
has been thrown in some directions on the 
subject. Many of those sub-tropical diseases, of 
which malaria is a type in man, and, say, red- 
water and South African horse-sick ness in 
animals, are now known to be caused by micro- 
organisms, which are transtnitted to them by 
the medium of certain insects, such as mosquitos 
and ticks: so that their occurreuce connot be 
said to be directly due to climatic influences. 
Indirectly, however, they are, for the disease- 
conveying insects only flourish in latitudes 
where the temperature and atmospheric moisture 
are such as to favor their development. 
The direct effect of atmospheric temperature 
is noticeable as a factor in disease, Apart from 
disease incidence due to sudden exposure to 
sun heat, long coutiuued exxcessive heat induces 
debility ana loss of tone and functional energy, 
leaving the system more open to attack by 
disease-producing agents. Conversely, the ad- 
~ vent of frost, or excessively cold weather, may 
cut short outbreaks uf microbian disease. On 
the other hand, long continued exposure to cold 
undoubtedly tends to lower vital energy, and 
so predisposes to disease. It has been frequently 
observed in America that the greatest prevalence 
and mortality of swine fever occurs in the 
southern States during the summer, and in the 
northern States during the wiuter months ; 
periods when the conditions of temperature und 
‘climate are such us to diminish the natural or 
physiological resistance to disease. ; 
Lung affections are much more prevalent in 
low-lying situations, w:th a moist foggy atmos- 
here, while horses and cattle reared at high 
‘altitudes, where the air is more rarifiedjand dry, 
are well known to have 1oore hardy disease- 
resisting constitutions. 
Locality. 
Certain diseases are observed to be more 
prevalent in some districts than others, and the 
increased prevalence can, in a number of in- 
stances, be shown to be due to local conditions 
“6 to 9 lbs each. 
THE AUSTRALIAN GARDENER. 
fs aren 
of soil and weather, or to localized customs of 
management. Fluke in sheep only prevails on 
low, marshy, or wet land, suitable for harboring 
the particular kinds of fresh water snails 
(physae), which are essential to certain stages 
in the life of the fluke parasite. In like manner 
anthrax, rheumatic affections, dysentery, Aus- 
tralian stringhalt, intestinal parasites, occur 
mostly on similar country. Foot-rot’in sheep is 
known to be of most frequent occurrence on 
very wet land, with a clay subsoil, or on dry 
gravelly country. Sand colic, impaction and 
paralysis of the bowels in horses are more pre- 
valent in dry sandy localities, where the soil is 
devoid of surface humus. In the wind and rain- 
swept gullies and ranges of Gippsland, and other 
hilly country, febrile diseases, colds, bronchitis, 
and other lung affections are more severe than 
in less tempestuous localities, and when con- 
tayious or infectious diseases, such as pleuro- 
pneumonia, swine fever, and strangles, obtain a 
footing in such districts, their spread is more 
rapid, and they are more fatal. In Australia 
the disease of horses known as “ nasal dise ise,” 
which is really a form of osteoporosis, is noticed 
to be more common in certain localities, as is 
also goitre and rickets in sheep. Similarly 
“coast disease” or “ cripples” when first of a 
character to demand attention, was almost con- 
fined to the coastal districts: 
Soil Exhaustion. 
The subject of soil-exhaustion, which is des- 
tinued to loom largely in connection with the 
health and well-being of stock in Australia, may 
be given brief attention here, for it is, in a great 
measure, a2 question of local stock management 
or agricultural customs. ver since shortly 
after the sheep industry got firmly planted 
throughout Australia, it has been known that 
certain tracts of country would become, after a 
shorter or longer lapse of time, “ sheep sick,’ 
aud now, at the end of fourteen or fifteen years 
from the establishment of the dairying industry 
sone areas, in Victoria wt least, are suspected 
of beiny “cattle sick.” This means that the 
virgin land, through continuous grazing without 
manurial or cultural assistance, has become 
deficient in certain mineral constituents, and 
that consequently those plants, to the growth of 
which such mineral matters were essential, haye 
died out, and plants of inferior quality, so far 
as milk production (or, in the case of sheep, 
wool production) is concerned, have taken their 
place.- In other words the grazing of one class 
of animal on the same land for a number of 
years has almost completely altered the character 
of the herbage, and while the pasturage may 
look as well us ever, and may be as good for 
grazing another class of animal, its “ substance” 
for the purpose for which it has been used, hag 
vanished. It is estimated that the amount of 
nitrogen lost to the soil by means of milk 
removed from the farm averages 45 lbs per cow 
per annum; of phosphoric acid and potash from 
Taking even good land that 
will carry one cow to 3 acres, it will be seen 
that the land is being exhausted at the rate of 
10 lb uf nitrogen and 2 to 3 ibs of phosphoric 
acid and potash per acre per annum 
Throughout a period of prolonged drought, 
this form of soil-exhaustion is more quickly 
etfected. Most of the chemical elements which 
form the mineral food of plants exist in some 
form, aud in minute quantities, in the air, and 
may be brought down and supplied to the soil 
by means of rain. The amount of nitrogen in 
the form of ammonia that is carried to the soil 
by rain in country districts during an ordinary 
season is equivalent at 44 ibs per acre per 
unnum. In the neighborhood of townsa greater 
amount is deposited, and therefore it is not in 
respect of nitrogen that the soil becomes ex-, 
hausted, But pnosphoric acid, in the form of 
phosphate of lime, is deposited by pau are 
extent of only half a pound per acre; 80 ni 
the deficiency produced by grazing milking co i 
is not made up for naturally, and See re 
this essential soil constituent goes 00 4 ae 
rate of at least 2lbs per acre per a 
amount equivalent to 10 lbs of 20 per pars 
superphosphate. In dry seasons the eae 
tious supply of mineral matter, by means se 
rain, fails, and the deficiency becomes mo 
pronounced. 
Overstocking. 
The subject of overstocking may be briefly 
adverted to. Apart from the il) effects of as 
tinuous grazing just mentioned, and wile 
become much increased when paddocks ane ; 
overstocked, and apart also from the ac 
fouling of the herbage by excess of SES 
discharges, and by “the tramp of many feet, 
there is the further disadvantage that the goo 
grasses a.e continuously eaten off as they ange 
into growth, and are thus prevented from A - 
ing. In this way the extirpation of much whole- 
some herbage is hastened. At the same time, 
useless or actually harmful and noxious plants 
which are not eaten by stock until the pasture 
is bare of nutritious grasses, are allowed to seed, 
uutil eventually the innutritious herbage pre- 
dominates, ths good grasses having been eaten 
out A familiar instance is the graduul usurpa- 
tion of a pasture by Yorkshire fog grass (holeus 
lenatus) where this grass has been sown with 
Sweeter grasses; the latter are eaten down Ccou- 
tinually, while the fog is neglected by stock 
owing to its harshness, and being a strong 
grower, it soon takes possession of the pasture. 
Again, the well-known rib-grass or plaintain 
(plantago lanceolata) being much relished by 
sheep, is a useful grass on sheep country ; cattle, 
however, neglect it, and on cattle runs it qu ickly 
becomes a nuisance, not only on account of its 
spread, but because its flat habit of growth 
entails great waste of ground surface that could 
otherwise be utilised by. more suitable grasses. 
‘Even in times of plenty, the folly of overstocking 
is not less acute, for then the noxious plants are 
left still more severely alone to propagate and 
spread their banefal presence over the pasture, 
occupying gronnd that would otherwise accom- 
modate herbage of more nutritious character. 
Truly the factors operating towards deteriora- 
tion of Australian pasture lands are many, and 
deserve thoughtful attention and action on the 
parc of all concerned. -At the risk of being 
charged with uttering a libel on the common 
sense of Australian farmers, a protest must be 
here entered against the suicidal and wasteful 
practice of burning off seeding grass during 
bountiful seasons, a practice which is carried 
out by not a few farmers in some highly-favored 
districts. They fear bush fires, and instead of 
mowing the super-abundance of seeding grass, 
and turaing it into hay or ensilage, as a standby 
for a time of scarcity, they thoughtlessly resort 
to the characteristically improvident method of 
the “fire stick.” 
{Environment.* 
Unwholesome surroundings may, according 
to their character and -iuteasity, be such as to 
excite disease or predispose the animal to an 
attack. Vitiated atmosphere, as a re ult of 
deficient ventilation and perflation, is often a 
coutributory cause of pneumonia, influeaza, and 
other debilitating diseases ia stabled animals, 
.So noticeable is the effect of insanitacy sur- 
roundings on the occurrence aud spread of 
certain diseases, that it has be:ome customary 
to group them together under the term “ tilth 
diseases.” By this is meant, not so much that 
filth in itself will cause these diseases as that 
their causative germs will find in the unclean 
