private study only. The thesis may not be reproduced elsewhere without
the permission of the Author.
\
A STUD Y OF FERT I LITY I N A HERD O F SOWS
A t h e s i s
p r e sented i n par t i a l ful f i lme nt o f the r e qu i r eme n t s for t he deg r e e
of
Master of Ag r ic u l tur a l Sc i e nce i n An ima l Sc i e nce
a t
Ma s s e y Un ive r s i ty
by
Ka spa r M i c hael He r mann
1980
ACKNOWLEDGEMENTS
I t i s w i t h s ince r e appr e c i a t ion that I ack nowle dge the
gu i d ance and counc i l o f both Mr . J . R . Car r and Doc tor W. C . Sm i th , Supe r v i so r s o f t he i nve s t ig a t ion p r e sen ted . The i r r e ady a s s i stance ha s made th i s an i n te r e s t ing and c ha l leng i ng a s s ignmen t .
Fo r w i l l ing co-ope r a t ion i n the p l ann ing and prepa r a t i on of compu ter progr amme s , I ex t end than k s to Mr s . N . S impson a nd Mr . L . Pear son o f the Ma s se y Unive r s i ty Compu t e r U n i t .
To Doc tor P r o fe s sor R . And e r son and Doc tor R . Pr ing l e , I w i sh to e xpr e s s my g r a t i tud e for many hour s o f d i sc u s s ion and g u i d ance in t he s ta t i s t i c a l anal y s i s o f r e levant d a t a of the s t ud y .
I would l i k e t o ac k nowledge the he l p and co-ope r a t ion o f the s t a f f o f the Ma s se y Un i ve r s i ty P i g Re se a r c h Ce ntr e ; in par t i c ul ar , Mr . K. B e s t , Mr . T . Roger s and Mr . G . Pear son for t he i r a s s i s ta nce and co -ope r a t ion .
Finan c i a l a s s i s t ance f r om the New Z e a l and Por k Ind u s t r y Co unc i l and t he Leon a r d Cond e l l Tr u st dur ing t he cou r se o f the se s tud i e s i s a l so acknowledged wi th gr a t i tud e .
I would l i ke to t han k Mr s . J . Cour t for typ ing t he manu sc r i p t .
Fina l l y , I mu s t a l so than k my w i fe Chr i s sy , for h e r pa t i en c e a n d e ncour ageme n t d u r i ng the pe r iod o f stud y .
CHAPTER
1
i i
TABLE OF CONTENT S
PAGE
ACKNOWLEDGEMENT S i
TABLE OF CONTENTS i i
L I ST OF TABLE S V
L I ST OF FriGURE S v i
INTRODUCT I ON 1 .
REVIEW OF L I TERATURE 2 .
I n t r oduc t ion 2 .
A . L ig h t 2 .
( 1 ) Ba s i c A spec t s 2 .
( a ) Gene r a l 2 .
( b ) M e c han i sm o f photope r iod ic
control . . . . . . . . . . . . . . . . . . . . 4 . ( c ) Pho tope r iod i c e f fe c t on
hormona l cyc l e s • • • •• • • • • . • • • s.
( d ) Summar y
( 2 ) Br e e d i ng P i g Per fo r mance ( a ) Gene r a l
( b ) A t t a i nme n t o f pube r ty ( c ) Oe s t r o u s be hav iour ( d )
( e ) ( f )
Ovu l a t ion r a te
Embr yon i c mor tal i ty Bod y we ight c hang e s ( g ) Conception r a te
( h ) Semen c h a r ac te r i st ic s
7 . 7 . 7 . 7 . 8 .
a.
1 1 . 1 2 . 1 2 .
a nd l i b i do • • • • • • •• • • • • • •• • • 13.
CHAPTER 1
2
PAGE
B . Amb i e n t Temper a t u r e 1 3 .
c.
( 1 ) Ba s ic A spec t s 13 .
( a ) Gene r al 13 .
( b ) C r i t ic a l pe r iod s 14 .
( i ) Pr ema t i ng 14 .
( i i ) Impl a n t a t ion 16 .
( i i i ) M id -ge s ta t ion 17 .
( c ) Reproduc t ion i n the ma le 18 . ( 2 ) B r e ed i ng P ig Pe r for mance 21 . ( a ) At t a i nmen t of pube r t y 2 2 . ( b ) O e s t r o u s c yc l e 2 2 . ( c ) I nt e r v a l we a n i ng-oe s t r o u s 2 3 .
( d ) Ovul a t ion r ate s 2 3 .
( e ) Fer t i l i z a t i on and concept ion
r at e s . . . . . . . . . . . . . . . . . . . . . . . 2 4 . ( f ) Embr yon i c mo r ta l i ty 2 5 .
( i ) Implantat ion 2 5 .
( i i ) M id -ge s ta t ion 2 6 .
( i i i ) Late ge s t a t ion 2 7 . ( g ) Seme n cha r a c te r i s t i c s and
l i b ido . . . . . . . . . . . . . . . . 2 8 .
Ind i r ec t Fac tor s 3 0 .
( a ) N u t r i t ion ( b )
( c )
He a l t h s t a t u s
Othe r b i o t i c fac to r s
3 0 31 3 2
MATERIAL S AND MET HODS
( 1 ) T he He r d and i t s Managemen t ( a )
( b )
Si z e and s t r u c t u r e Replaceme n t pol ic y
3 4 3 4 3 4
C HAPTER 2
3
4 5
( c ) Hea l th status (d )
( e ) . ( f ) ( g ) ( h )
Hou s ing
M a t i ng sys tem T ime of we a n i ng Feed ing
Par a s i te c on t r ol
( 2 ) Col l e c t ion of Data and St a t i s t ic a l
i v
PAGE 3 4 . 3 5 . 3 5 . 3 5 • 3 7 . 3 7 .
An a 1 y s i s . . . . • . . . • . . . • 3 8 . ( 3 )
( 4 ) RE SULT S
Me a su r e s o f Fe r t i l i ty S ta t i st i c a l Ana lyse s
{ A ) Far rowing Ra t e s ( 1 )
( 2 )
I n f l uence of mon t h of ma t i ng I n f l uence of breed
3 8 . 3 9 . 4 3 . 4 3 . 4 3 . 4 6 . ( B ) Re t u r n to Se r v ice Pa t te r n • • • • • • • • • . • . • . • 4 6 .
(c) L i t te r Numbe r s at B i r th 5 3 .
D I SCUSSION 6 2 .
SU��ARY AND CONCLU S I ON S 7 3 .
APPEND ICES 7 5 .
REFERENCE S 8 7 .
TABLE 1 . 1
2.1
3 . 1
3 . 2
3 . 3
3.4
3 . 5 3 . 6
L I ST OF TABLE S
PAGE A t t a i nme n t of Pube r ty i n G i l t s Kept Und e r
D i f fe r e n t,· L i g ht i ng Reg ime s . . . • . . . • • • • 9 . Monthly Numbe r o f Se r v ice s and Re su l t a n t
Far rowing s and Re tur n s for a He r d o f Sow s
Ove r a Seven Yea r Pe r iod . . . . . . • • • . . • . • • . 3 6 . Mon thly D i f fe r ence s ( % ) i n Farrowing to a l l
Se r v i c e s Recorded Dur i ng Each Mont h ( R e l a t ive t o Mon th Shown in Le ft Hand Col umn ) . . . . . 4 2 . Monthly D i f fer e nce s ( % ) i n Far row i ng Ra te to
I n i t i a l Se r v ic e s only Recorded Du r i ng Each Month ( Re l at ive to Month Shown i n Le f t Hand
Column ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5 . Mon thly D i f f e r e nc e s in the Pr opo r t ion o f
Re tur n s t o Se r v ice of Abnorma l Len g t h ( % )
�1 1 Se r v i c e s I nc l uded ( Re l at i ve to Month
Shown i n Le f t Hand Col umn ) . . . • . . . • . • • 4 9 . Monthly D i f fe r e nce s i n the Pr opor t ion o f
Retur n s t o Se r v ice of Abnormal Le ngth
Be tween Mont h s ( % ) to I n i t i a l Ma t in g s only ( Re l a t i ve to Mon t h Shown i n Le f t Hand
Column ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 . I n f l uence o f Br e ed o f Darn and Par i t y o f Tot a l
Numbe r o f B i r t h s pe r L i t te r . • . • • • • . • • . • • 5 6 . In fl uence o f B r e ed of Darn and Par i ty o f the
Numbe r o f L i ve B i r t h s pe r L i t t e r . • . . • . . • 5 8 •
•
FIGURE 3.1 3.2
3.3 3.4
3.5
3.6 3.7 3.8 3.9 4.1
4.2
LIST OF FIGURES
PAGE Mean effect of month of service on
farrowing rate to all recorded services.. 44.
Mean farrowing rate of purebred and
crossbred sows. . . 47.
A = all services B = initial services only Mean effect of month of service on
farrowing rate to initial services only... 48.
Mean effect of month of service on the proportion of returns of abnormal length
to all services.... . . 51.
Mean effect of month of service on the proportion of returns of abnormal length
to initial services only.. .. .. .. .. .. .. . . .. . . . 54.
Mean annual total litter size at birth ... 55.
Mean effect of month of service on mean
number of total births per litter... 57.
Mean annual number of live births per
litter... . . . 60.
Mean effect of month of service on mean
number of live births per litter... 61.
Relationship between mean monthly farrowing rate and mean monthly daily maximum
vi
temperature at time of mating... 67(a).
Relationship between mean monthly farrowing rate and mean monthly diurnal temperature
fluctuation at time of mating... 67(b).
