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THE PREDICTABILITY OP THE BUTTERFAT T RAN S KITT11'-GAB ILITY OP DAIRY BULLS
By JAMES PREDERIGK SMITHCORS
A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture a nd A pplied science in partial fulfillment of the requirements for the degree of DOCTOR OP PHILOSOPHY
Department of Animal Husbandry
1951
TABLE OP
CONTENTS
INTRODUCTION
1
R EVIEW OF LITERATURE I. II.
The heritability of butt; e r f a t
production
The prediction of t r a n s m i t t i n g
III. Environmental influences production
ability
upon m i l k
II.
6
and butterfat 11
PREDICTION OF BUTTERFAT T R A N S M I T T I N G A B I L I T Y IN THE MICHIGAN I N S T I T U T I O N H E R D S I.
4
OF BULLS
Source of data
20
Methods
22
RESULTS I. Correlation of average d e L x n - d a u g n t e r p r o d u c t i o n II. Per cent chance of p r e d i c t i n g certain limits
26
p r o d u c t i o n within 27
III. Correlation coefficients oetween dam-daughter production at v a r y i n g l e v e l s o f p r o d u c t i o n
29
IV. Comparison of rankings of* t r a n s m i t t i n g a b i l i t y w i t h actual daughter a v e r a g e
30
DISCUSSI ON I. II. III. IV.
Correlation analysis of
production
data
35
Diallel crossing
38
Environmental indices
42
Worksheets
45
SU MMA RY
47
REFERENCES
*9
APPENDIX
61
VITA Tile au tho r was
born Ma r c h 27, 1920 at Glassboro, New
Jersey an d spent his early life in a rvral background.
he
received the
B.S. degree from Rutgers University in 1941,
ing In dairy
husoandry.
major
The *:.S. degree was ob tained at
Cornell University in 1943 w h i l e an assistant in animal breeding. The author then entered the New Y o r k State Veterina ry College and received
the D.V.M. degree In 1945.
One yea r of this
time
was spent as
a m emb er of the Arm y veterinary training program*
In Nov ember 1945 the author was app oi n t e d Assista nt Pro fessor of An a t o m y at Mi chi gan State College whe re he entered the Graduate School in 1945.
He is the author or co- aut hor of two laboratory
textbooks and of four scientific articles in the field of endocrinology.
He is currently employed as Ass oc i a t e Professor
of A n a t o m y at M i c h i g a n State College.
INTRODUCTION On e o f tn e m o s t
important
problems
f a c i n g tiie d a i r y m a n
is tie p r e d i c t i o n o f w h i c h o f s e v e r a l p r o s p e c t i v e
sires
is
most l i k e l y to t r a n s m i t tiie ti.igh.est l e v e l o f b u t t e r f a t
produc
tion*
from
That no a c c u r a t e m e a n s
the m e a g e r p r o g r e s s pound a year,
in i m p r o v e m e n t
o f the p r o g r e s s
improvement
of p r o d u c t i o n ,
two d e c a d e s or longer.
that has
in environment.
P e w o f t n e s t u d i e s m a d e u p o n the have
oeen s u c c e s s f u l
tinguishing between hereditary and environmental
dicting
S t i l l f e w e r o f the t e c h n i q u e s Dutterfat
in d i s
factors
In
in c o m m o n u s e f o r p r e
p r o d u c t i o n r e c o g n i z e the
ment other than correcti