SOME ASPECTS OP FERTILITY IN ARABIAN HORSES IN IRAQ SY-5-14 AL-MURRANI.W.K. ft A.J.A.RASHED* College of Veterinary Medicine, Baghdad University, Alameriah , Baghdad , Iraq. INTRODUCTION Worm- blooded horses originates from the near Orient and the countries around the Mediterranean basin and are characterized by lightness , quality, fineness, courage and impetuosity .The influence of the Arabian horses on all wdrm blooded breeds and on the Thoroughbreds is not open to doubt.Lady Wentworth prese- nted an illuminating evidence on the preponderant influence of Arabian horses on modern Thoroughbred and on that the excellence of the latter could not have been attained without the free admixture with Arabian blood (Wynmalen , 1966). Very little was published on fertility trait in Arabian breed in its native habitat . This study was made possible by analysing records on some fertility aspects of a large number of mares and stallions kept at Abu-Guraib stud farm near BaghdadCLatit.33.7N. Longit.44.8E.) MATERIALS AND METHODS Two sets of records, one on 162 mares collected in 1976 and the other set on more than 160 mares(from 5 - 1 2 years) and 19 stallions (from 7 - 1 8 years) collected in 1981 were analysed. Informations obtained from the first set about the occurence of heat and its relation with the duration of daylight and atmos- pheric tempreture were used to restrict the breeding season to a period from 15 th of March to the 15 th of June. address: The D.G. Of The Animal Resources, Ministry of Agricul- ture and Agrarian Reforms, Iraq. 543
Transcript
SOME ASPECTS OP FERTILITY IN ARABIAN HORSESIN IRAQ S Y -5 -1 4
AL-MURRANI.W.K. ft A.J.A.RASHED*College of Veterinary Medicine, Baghdad University,
Alameriah , Baghdad , Iraq.
INTRODUCTIONWorm- blooded horses originates from the near Orient and the
countries around the Mediterranean basin and are characterized by lightness , quality, fineness, courage and impetuosity .The influence of the Arabian horses on all wdrm blooded breeds and on the Thoroughbreds is not open to doubt.Lady Wentworth presented an illuminating evidence on the preponderant influence of Arabian horses on modern Thoroughbred and on that the excellence of the latter could not have been attained without the free admixture with Arabian blood (Wynmalen , 1966).
Very little was published on fertility trait in Arabian breed in its native habitat . This study was made possible by analysing records on some fertility aspects of a large number of maresand stallions kept at Abu-Guraib stud farm near BaghdadCLatit.33.7N.Longit.44.8E.)
MATERIALS AND METHODSTwo sets of records, one on 162 mares collected in 1976 and
the other set on more than 160 mares(from 5 - 1 2 years) and 19 stallions (from 7 - 1 8 years) collected in 1981 were analysed. Informations obtained from the first set about the occurence of heat and its relation with the duration of daylight and atmospheric tempreture were used to restrict the breeding season to a period from 15 th of March to the 15 th of June.
♦address: The D.G. Of The Animal Resources, Ministry of Agriculture and Agrarian Reforms, Iraq.
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In addition to correlations of the occurence of heat with the duration of daylight and atmospheric tempreture, mean length of estrous cycle and duration , number of inseminations for effective conception, gestation period and birth rate were also calculated.
For calculating gestation period and number of natural inseminations ,mares were grouped into six groups ,one year each,starting from age of 5.The last group included mares from 10- 12 years old.
Statistical procedures were carried according to Snedecor and Cochran, 1968.
RESULTSGeneral Observations:
Most of the mares studied belong to four major Arabian families, namely 26.5# Hamdaniah, 21.5# Kuhailah, 19.2# Saglawiah and 18.0 # Munigiah. 45# of the stallions were Kuhailah , 34# were Saglawiah. The rest were different..
The prevalent colours among mares were the roan (58#),the chestnut (3 0#), the bay(8#) and the black(4#).Colours in their offspring were chestnut (75#), bay(19#5 and black(6# ).
Estrous cycles:Length of estrous cycles ranged from 14 -43 days with a mean
of 24.43±1.15 days.The duration was also variable and ranged from 2 -6 days in most of the mares, few lasted up to 11 days; the mean was 4.15 + 0.03<l*
Number of females showed heat varied with montnly mean duration of daylight, of atmospheric tempreture and with season of theyear (Table 1 and Figure 1 )J)he correlation between estrous cycle and monthly mean of daylight was positive and significant^.432.21).
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Table:l: The relation between mean atmospheric tempreture .mean duration of daylight and incidence of heat in the J1976 data;and,number of successful inseminations and of births in the 1 9 8 1 data.
1976 data 1981 dataMonth Mean temp. Mean daylight Estrous No.of inse- No.of
Table(2): Mean number of inseminations for effective preqnancy and of gestation period (in days)with its Ceefficient of Variation for diffident age groups •
Age(years) Number of inseminations gestation period C.V.̂ ofor effective preqnancy in (days )
4-5 2.67 + .28 u.
6 3.45 + . 6 0 “ 6
7 5.07 ± .78 i
8 2.71 + .44 «•
9 2.72 + . 4 9 a
1 0 - 1 2 2 . 9 0 ± . 6 2
344.71 + 19.65 2 1
34.9.45+ 9 . 2 1 9
351.13 + 4.41 5
350.21 + 3 . 8 6 4
356.18 + 3.41 3
349.72 + 4.62 4
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The c o r r e l a t i o n w ith a tm o sp h e r ic tem p re tu re was n o t s i g n i f i c a n t
( r r .0 6 + . 3 ) . I n th e mean t im e , th e c o r r e l a t i o n b etw een a tm osp h -
o r ic te m p r e tu r e and d u r a t io n o f d a y l ig h t was h ig h ( r ^ .7 6 f - .1 2 )
and s i g n i f i c a n t ( P ^ . 0 5 ) .
S ea so n o f th e y e a r showed a p rom inant e f f e c t on in c id e n c e o f
h e a t . 7 0 .5 # o f th e m ares showed e s t r o u s d u r in g S p r in g ( M arch, A p r i l
and M ay), 1 8 .5 # d u r in g Summer (J u n e , J u ly and A u g u s t ) ,6 .8 # d u r in g
W in ter( J a n u a r y , F eb ru ary and March) and o n ly 3 .7 # d u r in g Autumn.
The C h i-sq u a r e t e s t showed a s i g n i f i c a n t s e a s o n a l e f f e c t ( P < ^ .0 0 l )
w ith th e h ig h e s t in c id e n c e d u r in g Spring.A m ong S p r in g m o n th s ,th e
in c id e n c e was 6 7 .6 , 1 9 .9 and 1 2 .5 # f o r March .A p r i l and May s u c c
e s s i v e l y .
Number o f I n s e m in a t io n s f o r s u c c e s s f u l p reg n a n cy and B ir th r a t e :
Number o f in s e m in a t io n s le d t o s u c c e s s f u l p rgn an an cy was
c a lc u la t e d and p r e s e n te d in t a b l e ( 2 ) . I t was s i g n i f i c a n t l y h ig h e r
d u r in g a g e 7 v e r s u s a l l o th er a g e s (P 0 ° 5 ) e x c e p t v e r s u s age o f 6 .
The 1981 d a ta showed t h a t a l l s u c c e s s f u l in s e m in a t io n s ( t h o s e le d
t o p reg n a n cy ) w ere d u r in g S p r in g and c o n s e q u e n t ly m ost f o a l i n g s
w ere d u r in g th e same s e a s o n ( t a b l e 1 ) .
F o a l in g p e r c e n ta g e ( number born to number in s e m in a te d ) i s
6 0 # - B ir t h s t h a t o ccu red d u r in g n ig h t w ere 6 0 # c o l t s . A l l b i r t h s
a t m id -d a y w ere c o l t s .
Few m ares s u c c e s s f u l l y c o n c e iv e d d u r in g O ctob er and f i r s t
two w eeks o f Novem ber and produced norm al f o a l s .
G e s t a t in p e r io d :
Mean le n g t h o f g e s t a t i o n p e r io d s w ere c a l c u la t e d and p re
s e n te d i n t a b l e ( 2 ) . The ran ge o f means v a r ie d b etw een a minimum
o f 3 4 4 .7 1 d a y s a t a g e o f 5 t o mi maximum o f 3 5 6 .1 8 *tt"age o f 9 .
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sr s*% Ay/tvm m
No s i g n i f i c a n t d i f f e r e n c e was n o t ic e d b etw een any o f th e m eans.
The c o e f f i c i e n t o f v a r ia t io n was a l s o c a lc u la t e d and p re
s e n te d i n t a b l e ( 2 ) . I t was h ig h e s t ( 21 d u r in g a g e o f 5 th en
g r a d u a lly dropped t o a b o u t 4 ^ .
DISCUSSIONThe r e p r o d u c t iv e c y c le in th e mare i s s u b j e c t t o th e g r e a t e s t
v a r i a b i l i t y o f a l l d o m e s t ic an im als.S om e o f th e m ares ap p ear to be
t r u e l y p o l y e s t r o u s . In th e N orth ern H em isphere th e b e s t c o n c e p t io n
r a t e s o ccu r in m ares b red in th e p e r io d May t o J u l y . The same tr e n d
o ccu r in m ares in th e S o u th ern Hem esphere f o r c o r r e sp o n d in g s e a s o n s
( M elv in Sw enson ) .
The results presented in table (i) showed that though Arabian mares in Iraq showed a polyestrous behaviour but most of them came
to heat between March and May i.e. about two months ahead t o mares in the Northern Hemisphere; and that inseminations during thesem onths l e d t o s u c c e s s f u l p r e g n a n c ie s .
Mean le n g t h o f e s t r o u s c y c l e s r e p o r te d h e r e (2 4 .4 3 ± 1 .1 5 d)
i s lo n g e r th an t h a t r e p o r te d f o r European b r e e d s (2 1 -2 3 d ) .N e v e r -r * f f r t e i l a
t h e l e s s , Evans e t . a l . ( l 9 7 7 )f w ide ran ge o f 7 -1 7 5 d .
Mean d u r a t io n o f e s t r o u s c y c le in A rabian m ares i s 4 .1 5 ± .0 3 d .
R ep o rts on th e v a r i a b i l i t y o f t h i s t r a i t a r e m a n y (S w e n so n ,8 th .e d . ;
Evans e t . a l . , 1 9 7 7 ) .
The a s s o c i a t i o n b etw een d u r a t io n o f d a y l ig h t and in c id e n c e
o f e s t r o u s i s c l e a r ( F ig u r e l).N u m b er o f m ares showed h e a t in c r e a s e d
w ith th e in c r e a s e o f d a y l ig h t b u t up t o a c e r t a in p o in t th e n d r o p e d .
The e f f e c t o f l i g h t on s e x u a l se a so n in m ares i s r e p o r te d
by S t a b e n f e ld t and Hughes (C o le and C u p p s,1 9 7 7 ) . A s im i la r tren d
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l a n o t ic e d f o r I r a q i A rab ian m ares.T h e mare r e sp o n d s t o d e c r e a s in g
l i g h t by a g r e a t r e d u c t io n o f o v a r ia n a c t i v i t y ( e s t r o u s c y c le and
norm al c o n c e p t io n ) though th e r e p o n se i s s la w and may la g up to
6 m onths a f t e r Summer s o l s t i c e . S i m i l a r l y , th e r e s p o n s e t o in c r e a s in g
l i g h t ,an d th e resu m p tio n o f c y c l in g and n orm al c o n c e p t io n in S p r in g
i s n o t r e e s t a b l i s h e d u n t i l 3 -4 m onths a f t e r W in ter s o l s t i c e .
The data of this study might reflect that it is not only light duration but its combination with atmospheric tempreture that governs this attribute in Arabian horses of this area.
L ength o f g e s t a t io n p e r io d was w it h in th e ra n g e r e p o r te d f o r
o th e r b r e e d s in o th e r c o u n t r ie s s p e c i a l l y ex trem e c a s e s o f norm al
b ir t h s occu red 14 days b e fo r e due t im e or 3 -4 w eeks a f t e r ( A n d r i s t ) .
I t i s w orthy t o m en tion t h a t t h i s c h a r a c te r i s more v a r ia b le d u r in g
e a r ly a g e s .
SUMMARYRecords on a number of Arabian horses kept .in a govern
mental stud farm near Baghdad were analysed for some fertility attributes.lt was found that there is a positive correlation between duration of daylight and incidence of estrous, and that , there:t5 a significant seasonal effect.The majority of mares showed heat during Spring.lt was postulated that it is not only light but its combination with atmospheric tempreture that affect this trait and some other aspects of fertility in Arabian horses in Iraf*
R E S U M E N
Los controles sobre cierto numero de caballos Arabes mantenidos en una cuadra gubernamental cerca de Bagdad, tomaron en cuenta algunos atributos de fertili-
550
dad, encontrandose que existe una correlacibn positiva en la duracion de 1 a luz solar y la frecuencia del estro, lo que constituye un efecto estacional significativo. La m a y or la de las yeguas demostraron calores durante la primavea*a . Se senalo que
no es solo la luz, sino su combinacion cOn la temparatura atmosferica lo que afec- ta a este caracter y a algunos aspectos de la fertilidad en el caballo arabe de Iraq.
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