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Relationship between signalment
and reproductive anamnesis data and result
of artificial insemination with cooled semen
in the mare
I. Cerchiaro1, M.E. Falomo2, R. Mantovani1
1
Dipartimento di Scienze Zootecniche Università degli Studi di Padova
2
Medico Veterinario Libero Professionista Padova
Corresponding author: Ilaria Cerchiaro. Dipartimento di Scienze Zootecniche Università degli Studi di
Padova. Agripolis Viale dell’Università 16 35020 Legnaro Padova – Tel. 0498272791 – Fax: 0498272669/2633
– Email: [email protected]
RIASSUNTO – Relazione fra il segnalamento e l’anamnesi riproduttiva e l’esito dell’inseminazione artificiale con seme refrigerato nella cavalla. Al fine di offrire un valido aiuto per un corretto approccio alla cavalla da destinare all’inseminazione artificiale, sono stati raccolti e studiati i dati relativi all’esame clinico di 73
cavalle di diverse razze e differenti proprietari fecondate con seme refrigerato da uno stesso veterinario nella
stagione di monta 2004. I dati, riportati su delle apposite schede tecniche veterinarie, sono stati analizzati in
funzione di aspetti segnaletici, anamnestici e clinici inerenti le fattrici. Il numero di dosi inseminanti per ciclo
estrale e l’esito del test di gravidanza con esame ecografico a 14 giorni dopo l’ovulazione sono risultati in
relazione rispettivamente con la razza (le cavalle non sportive hanno presentato un rapporto dosi/ciclo significativamente più elevato di quelle sportive; 2.1 vs 1.5; P<0.05) e con precedenti problemi di fertilità (le cavalle
fertili hanno presentato un 90% di probabilità di insuccesso dell’inseminazione artificiale in meno di quelle
ipofertili).
Key words: Clinical examination, Artificial insemination, Cooled semen, Mare.
INTRODUCTION – An accurate clinical examination and in particular a careful collection of both signalment and anamnesis data can be helpful to predict both the result of the artificial insemination and the
course of the pregnancy in the mare. In fact, age, breed, body condition, parity and reproductive pathologies
can affect the fertility of the mare in different ways (Heilkenbrinker et al., 1997). The old mare can delay the
entry into the breeding season or have irregular oestrous cycles, abnormal oocytes, a higher risk of reabsorption or abortion and an increased susceptibility to endometritis (Madill, 2002; Woods, 1989). The high parity
can be associated to an uterine angiosclerosis (Gruninger et al., 1998) and both the acute and the chronic
degenerative endometritis can be responsible of early pregnancy losses (Darenius, 1992; Ball, 2000). Therefore,
the aim of the study was to analyse the relationship between the clinical examination, and in particular the
signalment and the reproductive anamnesis, and the response of the mare to the artificial insemination with
cooled semen to give some useful guide lines for its correct reproductive management to the veterinarians.
MATERIAL AND METHODS – Clinical examination data of 73 mares (7 Haflinger, 7 Western, 9 Trotter,
22 Saddler and 28 Italian Heavy Draught) reared in 42 stud farms of the North-eastern Italy and inseminated
with cooled semen by the same veterinarian were collected at the end of the 2004 breeding season. Mares at
insemination were treated homogenously despite their previous reproductive problems or not. The semen used
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was diluted with Palmer’s extender (Palmer, 1984), cooled to 4°C and preserved at the refrigeration temperature till 6-8 hours from the collection. Data of every mare were reported on a special form divided into two different parts: the former for the signalment and the reproductive anamnesis and the latter for all the information related to the artificial insemination (state of both uterus and ovaries, date of insemination, result of pregnancy test with ultrasound scan on the 14th day after ovulation and all the possible hormonal and/or pharmacological treatments). Mares were divided into different classes of age (≤ or > 9 years), breed (sporting or not
aptitude), parity (0, 1 or ≥2 foalings, on average 4 foalings), anamnesis of endometritis (yes or not), previous fertility problems (yes or not, i.e. fertile or hypo-fertile), body condition score (B.C.S. of 1-3 or 4-5) and result of pregnancy test (positive or negative). In particular endometritis was diagnosed by bacteriological, cytological, histological and ultrasound examination. Data were processed by SAS statistical package (1990) to find all the possible relationships between the clinical examination and the result of the artificial insemination.
RESULTS AND CONCLUSIONS – The SAS System GLM Procedure found a Total R-Square of about
13% for the number of insemination doses per oestrous cycle (doses/cycle) when age, breed, parity, anamnesis
of endometritis, previous fertility problems, body condition score and result of pregnancy test were used as
explanatory variables (Table 1).
Table 1. Factors affecting the number of insemination doses per estrous cycle.
Source of Variation
Degrees of Freedom
Variance
P
1
1
1
2
1
1
1
64
5.7412
1.1841
0.9113
0.3404
0.7488
0.0008
0.0010
1.0584
*
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
-
Breed
Age
B.C.S.
Parity
Anamnesis of endometritis
Anamnesis of fertility problems
Pregnancy test
Error
This low value of the R-Square means a wide variability in the number of insemination doses per estrous cycle.
In fact, the ratio doses/cycle ranged from 1 to 6 in the study. Breed resulted the most important source of variation for doses/cycle accounting for the 57% of the total variation attributable to the ANOVA model (Table 1).
In fact, not sporting mares showed a significantly (P<0.05) higher number of insemination doses per oestrous
cycle in comparison with the sporting ones (2.1 vs. 1.5 respectively). A possible reason for this result could be
related to the cost of the insemination dose (the owners of the not sporting mares can afford a higher number
of insemination doses per oestrous cycle for the same price) and the reproductive management adopted by the
veterinarian. Other factors such as age, parity, previous reproductive pathologies and fertility problems, B.C.S.
and result of pregnancy test showed no effects on the ratio doses/cycle. Therefore, an old, skinny and multiparous mare with previous reproductive problems does not need a significantly higher number of insemination
doses per oestrous cycle in comparison with a young, maiden and healthy one with a good B.C.S.. The LOGISTIC Procedure did not show any significant effects such as age, breed, parity, anamnesis of endometritis, B.C.S.
and doses/cycle on the negative pregnancy diagnosis. The only exception was the hypo-fertile mare (P<0.05)
(Table 2 and 3). In fact, the mares without previous fertility problems showed a 90% lower probability of not
getting pregnant than the hypo-fertile ones. The study indicates that the information given by the signalment
and the reproductive anamnesis of the mare can be useful to predict the result of the artificial insemination
with cooled semen and then choose the best reproductive management for the horse. Therefore, signalment and
reproductive anamnesis data have always to be collected with high care and concern by veterinarians. Finally,
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it has to be pointed out that this study is only a preliminary research because it was carried out in one breeding season and then a higher number of data would be useful to extend the results obtained up to now.
Table 2. Factors affecting a negative pregnancy diagnosis.
Effect
Breed
Age
B.C.S.
Parity
Anamnesis of endometritis
Anamnesis of fertility problems
Doses/cycle
Table 3.
Wald Chi-Square
Pr>Chi-Square
P
0.2135
0.0633
1.1282
0.0531
2.2088
3.8024
0.0132
0.64
0.80
0.29
0.97
0.14
0.05
0.91
n.s.
n.s.
n.s.
n.s.
n.s.
*
n.s.
Odds ratio for each comparison within factors affecting a negative
pregnancy diagnosis.
Effect
Breed:
not sporting vs. sporting
Age:
≤ vs. > 9 years
B.C.S.:
1-3 vs. 4-5
Parity:
0 vs. ≥2 foalings
1 vs. ≥2 foalings
Anamnesis of endometritis:
not vs. yes
Anamnesis of fertility problems:
not vs. yes
Doses/cycle
Point Estimate
95% Wald Confidence
Limits
Lower
Upper
0.593
0.064
5.455
1.294
0.174
9.620
2.601
0.446
15.169
1.307
1.068
0.133
0.108
12.813
10.577
0.231
0.033
1.596
0.108
0.934
0.012
0.290
1.011
3.010
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