1 Fes., 1902.) QUEENSLAND AGRICULTURAL JOURNAL. 91 
th . ° 
Dairying. 
CAUSES OF VARIATION IN THE BUTTER-FAT PERCENTAGES 
OF MILK AND CREAM. 
By G. S. THOMSON, N.D.D., 
Government Dairy Instructor, South Australia. 
As this subject has been freely discussed of late and various opinions 
expressed, it will be to the gain of suppliers and butter-makers alike to have an 
explanation given of the various causes that influence the quality of milk and 
cream. 
THE Cow. 
Letus first of allconsider the cowand her milk. Cows in good health and those 
that are well fed and well treated will give an almost equal daily quantity and 
quality of milk extending over a period of weeks. On the other hand, when 
they are either unhealthy or irregularly fed, and the quantities of feed insuf- 
ficient to meet requirements, the milk yield and butter-fat percentages will 
fluctuate morning and afternoon. Again, the hours of milking, times milked, | 
and efficiency or otherwise of milkers will all influence very considerably the 
morning and afternoon quantity and richness of the yield. Let us discuss the 
hours of milking and see what results have already demonstrated. In experi- 
ments conducted cows were milked on three different farms at the following 
hours :— 
‘ a p.m. 
IN OUBLIE Ss 08 ca .. 345 and 3-45 
INon 2 nett ord} bon tmil %, 
No.3 ... ae 33 ... 9380 ,, 12:30 
For convenience we will take one cow in each lot, giving her average daily 
milk yield and butterfat percentage for one week of the test. 
Quantity of Milk. Quality of Milk. 
Morning. Afternoon. Morning. Afternoon, 
lb. o My, Per Cent. lat. Per Cent. Fat. 
No. 1 Pst, seas eae) G WE oy, 52 
No. 2 Al wn be Cater © 3:9 46 
No. 3 oe ax a 6 wens 3°9 5:0 
These extracts furnish evidence that the fluctuation principally occurred as 
a result of the hours of milking being unevenly balanced. What then must be 
the daily differences when there is a disregard of attention to other equally 
important factors. Take, for example, rough treatment of cows either 
immediately before or during the operation of milking. Experience has shown 
to everyone that heavy losses in quantity and quality of milk are sustained 
when a cow becomes nervous by fright, and these ruinous changes are 
recognised to be of almost immediate occurrence in the udder of the animal. 
So strikingly injurious are they that in some instances the effects would 
seem incredible. Take this illustration as an example. Two cows were milked 
at 5 a.m. and 5 p.m., morning and afternoon; the following morning both were 
milked at the same hours, but, contrary to rules, the animals were hunted into 
their milking bails and otherwise roughly handled. The results of the evil 
practice will be found in the accompanying table :— 
Before Rough Usage. After Rough Usage. 
Quantity of Milk. Quantity of Milk. 
Morning. Afternoon, Morning. Afternoon 
Tb. lb. Jb. Tb. 
No. 1 om on ARES 11$ nt 6 10 
No. 2 or on 9 oon 5 8 
‘Per Cent. Fat. Per Cent. Fat 
No. 1 xx: ax Bi) 4, 2 «BE 
cg 3 
No. 2 ot an iit 42 ott 31 38 
