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Seasonal variations of semen quality in male goats: Study of sperm abnormalities
Theriogenology
38:115-125,
SEASONAL
1992
VARIATIONS OF SEMEN QUALITY IN MALE GOATS: STUDY OF SPERM ABNORMALITIES
J. Rota’, E. Martinez’, M.A. Sanchez-Valverde’, and J.M. Vazquez’
S. RuiZ
Departments
of ‘Animal Pathology and *Animal Biology Facultad de Veterinaria Universidad de Murcia, 30071 Murcia, Spain
Received
for publication: Accepted:
December 6, 1990 May 1, 2992
ABSTRACT The type, frequency and seasonal variation of sperm abnormalities in male goats inhabiting in Mediterranean region were evaluated. Semen was collected twice a week with an artificial vagina from 9 lo-month-old MurcianoGranadina male goats weighing 41 to 48 kg. Distal cytoplasmic droplets and acrosomal damage were the predominant abnormalities. Increase in age (10 to 27 months) did not reveal itself as a main effect on the occurrence of sperm abnormalities. All types of sperm abnormalities studied showed significant (PcO.01) seasonal variation. The poorest quality semen was collected during winter and spring. In spite of a seasonal variation in sperm quality, semen of Murciano-Granadina goats in the Mediterranean area is good all year long, since the proportion of abnormal spermatozoa was well within the accepted range for normal fertility. Key words: goat, sperm morphology,
acrosome, daylength, air temperature
INTRODUCTION Good semen quality is essential for the success of an artificial insemination program. To assure semen quality, morphological examination of spermatozoa can be conducted (1). A finding of a high proportion of abnormal spermatozoa has been shown to influence fertility adversely in domestic animals, including goats (2-4). It is well known that the quality of semen in goats varies depending on the breed, geographic location and season of the year (5-7). However, there is no information on the effect of season on sperm quality in goats in the Mediterranean region.
Copyright
0
1992
Butterworth-Heinemann
116
Theriogenology
The Murciano-Granadina is one of the most important dairy goat breeds found in the Mediterranean area, and as such this breed has substantial economic significance. The purpose of this study, therefore, was to determine 1) the type and frequency of the most common sperm abnormalities as well as the proportion of spermatozoa with acrosome damage and 2) the seasonal effect on the ocurrence sperm defects in mature Murciano-Granadina goats. MATERIALS Geography
AND METHODS
and Climate
This study was carried out at the Estacion de Mejora Ganadera (EMEGA) in Murcia, Spain. The Murcia Valley is located at a latitude of 37” 59’ N, a longitude of 1” 08’ W, and an altitude of 63 m. The experiment was conducted over an B-months period, from October 1987 to March 1989. Seasonal variation in the different types of sperm abnormalities was observed in 1988 year. The Murcia Valley has 4 seasons: winter (January to March); spring (April to June); summer (July to September); and fall (October to December) (8). Maximum air temperature varies from 15.7”C (January) to 33.1”C (August) and minimum air temperature from 4°C to 19.2”C. Relative humidity is always above 50% and the daylength varies from 9h 30min (December, 21st) to 14h 54min (June, 21st). Animals From among the animals available at the experimental station at Mejora Ganadera, 9 Murciano-Granadina male goats were chosen ramdomly. They were 10 months old when the study commenced and weighed from 41 to 48 kg. All the bucks were housed in a covered shelter with an extra open-air area, and were allowed to roam freely. The goats were given hay and water ad libitum and were fed a 16% protein supplement each morning. A general management schedule for deworming, disease prevention and hoof trimming was followed. Semen Collection
and Evaluation
Semen was collected was by artificial vagina (1) twice a week. This was considered sufficient to detect any significant seasonal variation in semen quality (9). An ovariectomized doe was used as a mount animal for semen collection. Since there were occasions when the goats failed to mount or to ejaculate, some ejaculates were not available. Immediately following collection, the ejaculates were transferred to the laboratory and immersed in a warm water bath at 37°C and care was taken to expose the semen to any unfavorable conditions during or after collection.
117
Theriogenology
In the laboratory, the proportions of spermatozoa with an abnormal morphology and with damaged acrosomes were determined in wet preparations of fresh semen fixed in phosphate buffered 2% glutaraldehyde solution (10). Then 400 and 200 spermatozoa were counted, respectively, from each preparation under the phase contrast microscope at the magnification of 1000x. Morphologic abnormalities were classified under head, midpiece and tail defects. In addition, ocurrence of proximal and distal cytoplasmic droplets and detached heads was also recorded (2). Statistical
Analysis
The results were analysed starting from data collected in each individual ejaculate using all individual ejaculates as data points. Beginning with data from 1988, the annual mean and the seasonal and monthly variation in sperm defects were examined by analysis of variance with a model that included the effects of animal, season and month using General Linear Model Procedures of the Statistical Analysis System (11). Comparisons between means of the d:.fferent seasons and of months were performed using Duncan’s Multiple Range Test. The effect of age was determined by examing semen samples collected from the goats at 10 to 12 months of age (fall 1987, Period A); at 13 to 15 months (winter 1988, Period B), at 22 to 24 months (fall 1988, Period C); and at 25 to 2’7 months (winter 1989, Period D). Comparisons between means of the two fall periods (A vs C) and between two winter periods (B vs D) were made by Student’s t-test (12). The results are expresed as percentages (mean ? SEM). RESULTS The types of sperm abnormalities recorded in this work (morphologic defects and acrosome damage) were present in the semen of all 9 MurcianoGranadina goats. Individual variation was significant (PcO.01) for any of the sperm abnormalities examined. The mean percentage values for each morphologic defect were as follows: deformed sperm heads, 0.19 (+ 0.01); midpiece defects, 0.58 ( f 0.02); tail defects 1.32 (+ 0.04); proximal droplets, 0.31(+ 0.01); distal droplets, 4.86 (2 0.12); and detached sperm heads, 0.67 (? 0.02). The predominant defects of sperm head were macro- and micro-cephalic head; in the midpiece was distal reflex and the sperm tail were mostly coiled and looped principal piece. The mean percentage of spermatozoa with damaged acrosome ranged from 3.53 (kO.22) to 11.15 (:i- 0.58). The predominant types of acrosome defects were knobbed acrosome, vacuolation of the acrosome region and detached acrosomal membranes.
118
Theriogenology
The type and/or occurrence of sperm abnormalities showed high fluctuations over the experimental period. The pattern of variation is shown in Figures la and lb. Although the percentage of the total number of spermatozoa with abnormal morphology at 10 to 12 months of age was higher than at 22 to 24 months (P < 0.05), the increase in age (10 to 27 months) did not reveal itself as a main effect on the occurrence of sperm abnormalities in MurcianoGranadina male goats. The annual variation in sperm defects is illustrated in Figures la, lb and 2. All the sperm defects analyzed were significantly influenced by season (PC 0.01). Monthly variations were also significant (PcO.01). The incidence of spermatozoa with morphologic abnormalities in winter was almost twice that as in spring, summer or fall. All types of morphologic abnormalities showed monthly variations with the highest percentages between January and March. A high percentage (P < 0.05) of spermatozoa with distal droplets was also found in August. The proportion of spermatozoa with acrosome damage followed a different seasonal pattern from that of the morphologic defects. The incidence of spermatozoa with acrosome damage was highest (P < 0.05) during the winter and spring seasons. The monthly peak ocurred between February and May (P < 0.05). A high percentage (P < 0.05) of spermatozoa with damaged acrosome was also found in December. DISCUSSION The yearly sperm quality of Murciano-Granadina goats in our present study was similar to that reported for Toggenburg (5), African dwarf (13) and Nubian goats (3, 14), and was higher than that of Red Sokoto goats (15). Evans and Maxwell (l), reporting on small ruminants, considered semen with 15 to 20 % sperm abnormalities to be normal and of good fertilizing quality. If this is true also for the Murciano-Granadina breed of goats, then the males our study were well within the range of normal fertility. The predominant morphologic defect was that of distal cytoplasmic droplets. This has been reported as the most common sperm abnormality in Barbary bucks (16) and in Ile-de-France rams (17). The cause for spermatozoa with cytoplasmic droplets has been related to disturbances in sperm maturation or in epididymal dysfunction (4, 18, 19). Nevertheless, distal droplets are not considered to be a serious problem for normal fertility (4). Like ram semen (20), in goat ejaculates one of predominant sperm defect was abnormal acrosome, sometimes spermatozoa with this defect also had others defects on the head or midpiece (21). Acrosomal changes in the spermatozoa probably result from abnormal spermiogenesis (4, 17).
119
Theriogenology
/ ABNORMAL MORPHOLOGY 1 (%I 16 1 4i 1 Z! I
;I-“Ott
+,
,
,__ A,
Nov Dee Jan Feb Mar Apr May Jun Jul Aug Sep Ott
1987
1988
+,
Nov Dee Jan Feb Mar
1989
AGE (months) A: 10 to 12 / C: 22 tO 24
Figure la.
B: 13 to 15 D: 26 to 27
Effect of age on total percentage of spermatozoa with an abnormal morphology in 9 Murciano-Granadina goats.
120
Theriogenology
ACROSOME DAMAGE 1 (46)
I
16;
A vs C: N.S. B vs D: N.S.
14; 12
A
21
B
,0’
I Ott
I
I
I
I
C ---_L__
LII
Nov Dee Jan Feb Mar Apr May Jun Jul Aug Sep Ott
D ‘_;I(
NW Dee Jan Feb Mar
.
.
1987
Figure lb.
1988
Effect of age on percentage of spermatozoa acrosome in 9 Murciano-Granadina goats.
1989
with damaged
Therrogenology
121
TYPES
OF SPERM
MORPHOLOGIC
ABNORMALITIES 6
x
._
0 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Ott
Nov
l
winter
Figxe
-e-
Sperm
*
Proximal
2.
head droplets
Monthly variations Murciano-Granadina
spring
summer
.
fall
*
Middle
piece
+
Sperm
-
Distal
droplets
+
Detached
on sperm morphological goats.
Dee
toil head
abnormalities
in 9
122
Theriogenology
In general, the sperm quality of Murciano-Granadina goats in our study was not influenced by age. Similarly, other works have shown that age-related effects on the occurrence of sperm abnormalities are limited in goats (3, 14). Murciano-Granadina goats produced good-quality semen at 8 to 10 months of age; further increase in age did not seem to have a main effect on sperm quality (22). The effect of season on sperm quality was evident in our study by the increased percentage of morphologically abnormal spermatozoa in the ejaculates of goats from January to April and by an increased proportion of spermatozoa with acrosome damage from January to June. A similar trend in Nubian goats was reported by Skalet et al. (3) and in ram breeds by Colas (17) Amir et al. (20) and Colas et al. (23). Seasonal variation in ruminant semen has been associated with weather conditions such as sinusoidal changes of daylength or/and air temperature variations (6, 23, 24). In rams, Colas (17) and Colas et al. (23) attribute the seasonal variation on sperm quality to the sinusoidal changes of daylength, with the highest percentages of sperm abnormalities occurring during periods of increased daylength. The results presented in our study confirm this seasonal pattern; the highest percentages of abnormal spermatozoa were recorded in the winter and at the beginning of spring (increasing daylength period). In a previous study with Murciano-Granadina goats from the Mediterranean region, we showed significant seasonal variation (P
123
Theriogenology
REFERENCES 1.
Evans, G. and Maxwell, W.M.C. Salamon’s Artificial Insemination Sheep and Goats. Buttetworths, Sydney, 1987, pp. 85-91.
2.
Sekoni, V.O. and Gustafsson, B.K. Seasonal variations in the incidence of sperm morphological abnormalities in dairy bulls regularly used for artificial insemination. Br. Vet. J., m:312-317 (1987).
3.
Skalet, L.H., Rodrigues, H.D., Goyal, H.O., Maloney, M.A., Vig, M.M. and Noble, R.C. Effect of age and season on the type and occurrence of sperm abnormalities in Nubian bucks. Am. J. Vet. Res., 49 (8):12841289 (1988).
4.
Barth, A.D. and Oko, R.J. Abnormal Morphology of Bovine Spermatozoa. Iowa State University Press, Ames, IA, 1989, pp. 130-271.
5.
Eaton, O.N. and Simmons, V.L. A semen study of goats. Am. J. Vet. Res. Q:537-544 (1952).
6.
Corteel, J.M. Collection, processing and artificial insemination of goat semen. In: Gall, C. (ed), Goat production. Gall, C. ed., Academic Press, Inc., London, 1981, pp. 171-191.
7.
Chemineau, P. Influence de la saison sur l’activite sexuelle du cabrit creole male et female. Ph.D. Thesis, Universite des Sciences et Techniques du Languedoc, 1986.
8.
Ministerio de Agricultura, Pesca y Alimentacion (M.A.P.A.). Atlas agroclimatico national de Espaiia. Direction General de la Production Agraria, Madrid, 1986, pp. 657-689.
9.
Corteel, J.M. Production, storage and insemination of goat semen. Management of Reproduction in Sheep and Goat Simposium. pp. 41-57 (1977).
10.
Pursel, V.G. and Johnson, L.A. Glutaraldehyde fixations of boar spermatozoa for acrosome evaluation. Theriogenology 1:638-641(1974).
11.
Statistical Analysis System (SAS). SAS User’s Guide. Institute Inc., Cary, NC, 1985.
12.
Steel, R.G.D. and Torrie, J.H. Principles and Procedures of Statistics: A Biometrical Approach. McGraw-Hill, New York, 1980.
of
Statistics. SAS
124
Theriogenology
13.
Mann, J. Spermatological investigations in African dwarf goats (Capra hircus L.) kept in Germany. Anim. Res. Develop., I&86-100 (1981).
14.
Hibbert, L.M., Rodrigues, H.D., Noble, R.C. and Vig, M.M. Effects of age and season on sperm abnormalities in Nubian goats. Anat. Histol. Embryol., 15:173, abstr. (1986).
15.
Salau-Daudu, C. Spermatozoa1 output, testicular sperm reserves and epididymal storage capacity of the Red Sokoto goats indigenous to northern Nigeria. Theriogenology a:317-324 (1983).
16.
Chaudhry, S.A. and Mahmood, U.H. Some observations on semen collection technique and morphological abnormalities of goat bucks spermatozoa. Pakistan Vet. J., 4:227-228 (1984).
17.
Colas, G. Variations saisonnieres de la qualite du sperme chez le belier Be-de-France. I. Etude de la morphologie cellulaire et de la motilite massale. Reprod. Nutr. Develop. a:1789-1799 (1980).
18.
Ott, R.S., Heath, E.H. and Bane, A. Abnormal spermatozoa, testicular degeneration and varicocele in a ram. Am. J. Vet. Res. G:241-245 (1982).
19.
Thilander, G., Settergren, I. and Ploen, L. Abnormalities of testicular origin in the neck region of bull spermatozoa. Anim. Reprod. Sci. &151-157 (1985).
20.
Amir, D., Gacitua, H., Ron, M. and Lehrer, A.R. Seasonal variation semen characteristics and fertility of Finn cross rams subjected frequent ejaculation. Anim. Reprod. Sci. 111:75-84 (1986).
21.
Savage, N.E. Infertility in a ram associated with a knobbed acrosome abnormality of the spermatozoa. Can. Vet. J. a:126-127 (1984).
22.
Rota, J., Martinez, E., Vazquez, J.M., Ruiz, S. and Coy, P. de la edad sobre 10s parametros reproductivos de1 macho raza Murciano-Granadina (Reproductive parameters of Granadina male goats at different ages). Arch. Zootec. (1991).
23.
Colas, G., Guerin, Y., Lemaire, Y., Montassier, Y. and Despierres, J. Variations saisotieres du diametre testiculaire et de la morphologie des spermatozo’ides chez le belier Veendeen et chez le belier Texel. Reprod. Nutr. Develop. 24:863-875 (1986).
in to
Influencia cabrio de Murciano@:173-179
Theriogenology
125
24.
Rekwot, P.I., Voh, A.A., Jr., Oyedipe, E.O., Opaluwa, G.I., Sekoni, V.O. and Dawuba, P.M. Influence of season on characteristics of the ejaculate from bulls in an artificial insemination centre in Nigeria. Anim. Reprod. Sci. U:187-194 (1987).
25.
Rota, J., Martinez, E., Vazquez, J.M., Ruiz, S. and Coy, P. Influence of season on testicle size and libido in male goats from the Mediterranean area. Anim. Prod. 52:317-321 (1991).
26.
Lincoln, G.A. Seasonal aspects of testicular function. In: Burger, H. and Kretser, D. (eds.), The Testis. Second Edition. Raven Press, Ltd., New York, 1989, pp. 329-385.
38:115-125,
SEASONAL
1992
VARIATIONS OF SEMEN QUALITY IN MALE GOATS: STUDY OF SPERM ABNORMALITIES
J. Rota’, E. Martinez’, M.A. Sanchez-Valverde’, and J.M. Vazquez’
S. RuiZ
Departments
of ‘Animal Pathology and *Animal Biology Facultad de Veterinaria Universidad de Murcia, 30071 Murcia, Spain
Received
for publication: Accepted:
December 6, 1990 May 1, 2992
ABSTRACT The type, frequency and seasonal variation of sperm abnormalities in male goats inhabiting in Mediterranean region were evaluated. Semen was collected twice a week with an artificial vagina from 9 lo-month-old MurcianoGranadina male goats weighing 41 to 48 kg. Distal cytoplasmic droplets and acrosomal damage were the predominant abnormalities. Increase in age (10 to 27 months) did not reveal itself as a main effect on the occurrence of sperm abnormalities. All types of sperm abnormalities studied showed significant (PcO.01) seasonal variation. The poorest quality semen was collected during winter and spring. In spite of a seasonal variation in sperm quality, semen of Murciano-Granadina goats in the Mediterranean area is good all year long, since the proportion of abnormal spermatozoa was well within the accepted range for normal fertility. Key words: goat, sperm morphology,
acrosome, daylength, air temperature
INTRODUCTION Good semen quality is essential for the success of an artificial insemination program. To assure semen quality, morphological examination of spermatozoa can be conducted (1). A finding of a high proportion of abnormal spermatozoa has been shown to influence fertility adversely in domestic animals, including goats (2-4). It is well known that the quality of semen in goats varies depending on the breed, geographic location and season of the year (5-7). However, there is no information on the effect of season on sperm quality in goats in the Mediterranean region.
Copyright
0
1992
Butterworth-Heinemann
116
Theriogenology
The Murciano-Granadina is one of the most important dairy goat breeds found in the Mediterranean area, and as such this breed has substantial economic significance. The purpose of this study, therefore, was to determine 1) the type and frequency of the most common sperm abnormalities as well as the proportion of spermatozoa with acrosome damage and 2) the seasonal effect on the ocurrence sperm defects in mature Murciano-Granadina goats. MATERIALS Geography
AND METHODS
and Climate
This study was carried out at the Estacion de Mejora Ganadera (EMEGA) in Murcia, Spain. The Murcia Valley is located at a latitude of 37” 59’ N, a longitude of 1” 08’ W, and an altitude of 63 m. The experiment was conducted over an B-months period, from October 1987 to March 1989. Seasonal variation in the different types of sperm abnormalities was observed in 1988 year. The Murcia Valley has 4 seasons: winter (January to March); spring (April to June); summer (July to September); and fall (October to December) (8). Maximum air temperature varies from 15.7”C (January) to 33.1”C (August) and minimum air temperature from 4°C to 19.2”C. Relative humidity is always above 50% and the daylength varies from 9h 30min (December, 21st) to 14h 54min (June, 21st). Animals From among the animals available at the experimental station at Mejora Ganadera, 9 Murciano-Granadina male goats were chosen ramdomly. They were 10 months old when the study commenced and weighed from 41 to 48 kg. All the bucks were housed in a covered shelter with an extra open-air area, and were allowed to roam freely. The goats were given hay and water ad libitum and were fed a 16% protein supplement each morning. A general management schedule for deworming, disease prevention and hoof trimming was followed. Semen Collection
and Evaluation
Semen was collected was by artificial vagina (1) twice a week. This was considered sufficient to detect any significant seasonal variation in semen quality (9). An ovariectomized doe was used as a mount animal for semen collection. Since there were occasions when the goats failed to mount or to ejaculate, some ejaculates were not available. Immediately following collection, the ejaculates were transferred to the laboratory and immersed in a warm water bath at 37°C and care was taken to expose the semen to any unfavorable conditions during or after collection.
117
Theriogenology
In the laboratory, the proportions of spermatozoa with an abnormal morphology and with damaged acrosomes were determined in wet preparations of fresh semen fixed in phosphate buffered 2% glutaraldehyde solution (10). Then 400 and 200 spermatozoa were counted, respectively, from each preparation under the phase contrast microscope at the magnification of 1000x. Morphologic abnormalities were classified under head, midpiece and tail defects. In addition, ocurrence of proximal and distal cytoplasmic droplets and detached heads was also recorded (2). Statistical
Analysis
The results were analysed starting from data collected in each individual ejaculate using all individual ejaculates as data points. Beginning with data from 1988, the annual mean and the seasonal and monthly variation in sperm defects were examined by analysis of variance with a model that included the effects of animal, season and month using General Linear Model Procedures of the Statistical Analysis System (11). Comparisons between means of the d:.fferent seasons and of months were performed using Duncan’s Multiple Range Test. The effect of age was determined by examing semen samples collected from the goats at 10 to 12 months of age (fall 1987, Period A); at 13 to 15 months (winter 1988, Period B), at 22 to 24 months (fall 1988, Period C); and at 25 to 2’7 months (winter 1989, Period D). Comparisons between means of the two fall periods (A vs C) and between two winter periods (B vs D) were made by Student’s t-test (12). The results are expresed as percentages (mean ? SEM). RESULTS The types of sperm abnormalities recorded in this work (morphologic defects and acrosome damage) were present in the semen of all 9 MurcianoGranadina goats. Individual variation was significant (PcO.01) for any of the sperm abnormalities examined. The mean percentage values for each morphologic defect were as follows: deformed sperm heads, 0.19 (+ 0.01); midpiece defects, 0.58 ( f 0.02); tail defects 1.32 (+ 0.04); proximal droplets, 0.31(+ 0.01); distal droplets, 4.86 (2 0.12); and detached sperm heads, 0.67 (? 0.02). The predominant defects of sperm head were macro- and micro-cephalic head; in the midpiece was distal reflex and the sperm tail were mostly coiled and looped principal piece. The mean percentage of spermatozoa with damaged acrosome ranged from 3.53 (kO.22) to 11.15 (:i- 0.58). The predominant types of acrosome defects were knobbed acrosome, vacuolation of the acrosome region and detached acrosomal membranes.
118
Theriogenology
The type and/or occurrence of sperm abnormalities showed high fluctuations over the experimental period. The pattern of variation is shown in Figures la and lb. Although the percentage of the total number of spermatozoa with abnormal morphology at 10 to 12 months of age was higher than at 22 to 24 months (P < 0.05), the increase in age (10 to 27 months) did not reveal itself as a main effect on the occurrence of sperm abnormalities in MurcianoGranadina male goats. The annual variation in sperm defects is illustrated in Figures la, lb and 2. All the sperm defects analyzed were significantly influenced by season (PC 0.01). Monthly variations were also significant (PcO.01). The incidence of spermatozoa with morphologic abnormalities in winter was almost twice that as in spring, summer or fall. All types of morphologic abnormalities showed monthly variations with the highest percentages between January and March. A high percentage (P < 0.05) of spermatozoa with distal droplets was also found in August. The proportion of spermatozoa with acrosome damage followed a different seasonal pattern from that of the morphologic defects. The incidence of spermatozoa with acrosome damage was highest (P < 0.05) during the winter and spring seasons. The monthly peak ocurred between February and May (P < 0.05). A high percentage (P < 0.05) of spermatozoa with damaged acrosome was also found in December. DISCUSSION The yearly sperm quality of Murciano-Granadina goats in our present study was similar to that reported for Toggenburg (5), African dwarf (13) and Nubian goats (3, 14), and was higher than that of Red Sokoto goats (15). Evans and Maxwell (l), reporting on small ruminants, considered semen with 15 to 20 % sperm abnormalities to be normal and of good fertilizing quality. If this is true also for the Murciano-Granadina breed of goats, then the males our study were well within the range of normal fertility. The predominant morphologic defect was that of distal cytoplasmic droplets. This has been reported as the most common sperm abnormality in Barbary bucks (16) and in Ile-de-France rams (17). The cause for spermatozoa with cytoplasmic droplets has been related to disturbances in sperm maturation or in epididymal dysfunction (4, 18, 19). Nevertheless, distal droplets are not considered to be a serious problem for normal fertility (4). Like ram semen (20), in goat ejaculates one of predominant sperm defect was abnormal acrosome, sometimes spermatozoa with this defect also had others defects on the head or midpiece (21). Acrosomal changes in the spermatozoa probably result from abnormal spermiogenesis (4, 17).
119
Theriogenology
/ ABNORMAL MORPHOLOGY 1 (%I 16 1 4i 1 Z! I
;I-“Ott
+,
,
,__ A,
Nov Dee Jan Feb Mar Apr May Jun Jul Aug Sep Ott
1987
1988
+,
Nov Dee Jan Feb Mar
1989
AGE (months) A: 10 to 12 / C: 22 tO 24
Figure la.
B: 13 to 15 D: 26 to 27
Effect of age on total percentage of spermatozoa with an abnormal morphology in 9 Murciano-Granadina goats.
120
Theriogenology
ACROSOME DAMAGE 1 (46)
I
16;
A vs C: N.S. B vs D: N.S.
14; 12
A
21
B
,0’
I Ott
I
I
I
I
C ---_L__
LII
Nov Dee Jan Feb Mar Apr May Jun Jul Aug Sep Ott
D ‘_;I(
NW Dee Jan Feb Mar
.
.
1987
Figure lb.
1988
Effect of age on percentage of spermatozoa acrosome in 9 Murciano-Granadina goats.
1989
with damaged
Therrogenology
121
TYPES
OF SPERM
MORPHOLOGIC
ABNORMALITIES 6
x
._
0 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Ott
Nov
l
winter
Figxe
-e-
Sperm
*
Proximal
2.
head droplets
Monthly variations Murciano-Granadina
spring
summer
.
fall
*
Middle
piece
+
Sperm
-
Distal
droplets
+
Detached
on sperm morphological goats.
Dee
toil head
abnormalities
in 9
122
Theriogenology
In general, the sperm quality of Murciano-Granadina goats in our study was not influenced by age. Similarly, other works have shown that age-related effects on the occurrence of sperm abnormalities are limited in goats (3, 14). Murciano-Granadina goats produced good-quality semen at 8 to 10 months of age; further increase in age did not seem to have a main effect on sperm quality (22). The effect of season on sperm quality was evident in our study by the increased percentage of morphologically abnormal spermatozoa in the ejaculates of goats from January to April and by an increased proportion of spermatozoa with acrosome damage from January to June. A similar trend in Nubian goats was reported by Skalet et al. (3) and in ram breeds by Colas (17) Amir et al. (20) and Colas et al. (23). Seasonal variation in ruminant semen has been associated with weather conditions such as sinusoidal changes of daylength or/and air temperature variations (6, 23, 24). In rams, Colas (17) and Colas et al. (23) attribute the seasonal variation on sperm quality to the sinusoidal changes of daylength, with the highest percentages of sperm abnormalities occurring during periods of increased daylength. The results presented in our study confirm this seasonal pattern; the highest percentages of abnormal spermatozoa were recorded in the winter and at the beginning of spring (increasing daylength period). In a previous study with Murciano-Granadina goats from the Mediterranean region, we showed significant seasonal variation (P
123
Theriogenology
REFERENCES 1.
Evans, G. and Maxwell, W.M.C. Salamon’s Artificial Insemination Sheep and Goats. Buttetworths, Sydney, 1987, pp. 85-91.
2.
Sekoni, V.O. and Gustafsson, B.K. Seasonal variations in the incidence of sperm morphological abnormalities in dairy bulls regularly used for artificial insemination. Br. Vet. J., m:312-317 (1987).
3.
Skalet, L.H., Rodrigues, H.D., Goyal, H.O., Maloney, M.A., Vig, M.M. and Noble, R.C. Effect of age and season on the type and occurrence of sperm abnormalities in Nubian bucks. Am. J. Vet. Res., 49 (8):12841289 (1988).
4.
Barth, A.D. and Oko, R.J. Abnormal Morphology of Bovine Spermatozoa. Iowa State University Press, Ames, IA, 1989, pp. 130-271.
5.
Eaton, O.N. and Simmons, V.L. A semen study of goats. Am. J. Vet. Res. Q:537-544 (1952).
6.
Corteel, J.M. Collection, processing and artificial insemination of goat semen. In: Gall, C. (ed), Goat production. Gall, C. ed., Academic Press, Inc., London, 1981, pp. 171-191.
7.
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