Greyling, J.P.C.

Grobbelaar, J.A.N.

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Seasonal variation in semen quality of Boer and Angoragoat r€rms using different collection techniquesJ.P.C. Greyling andAnimal and Dairy ScienceJ.A.N. GrobbelaarResearch Institute, lreneSemen was collected weekly throughout the year from three Boer goat ramswith the aid of the artificial vagina and from two Angora and two Boer goatrams by means of electrical stimulation, to determine seasonal variation insemen quality. Semen characteristics monitored were volume, density,percentage of live sperm, percentage of abnormal sperm, pH and motility.No significant seasonal variation in semen quality was noted. ln the Boergoat (artificial vagina) a significant difference (P< 0,05) was obtained in thepercentage of live sperm for different months of the year, while the volume(P< 0,01) and pH (P< 0,O5) of ejaculates were significantly lower when col-lected by the artif icial vagina and the density and motil ity were significantly(P< 0,01) higher when compared with sperm collected by electrical stimula-tion. A negative correlation (-0,90) was obtained between the percentage oflive sperm and the percentage of abnormal sperm collected from Boer goatrams by the artificial vagina. The Angora goat produced an ejaculate with asignificantly higher motil ity (P< 0,01), density (P< 0,01) and lower volume(P< 0,05) than the Boer goat when electrically stimulated - a significant(P< 0,01)variation in pH between months was obtained by this method ofsemen collection. The artificial vagina proved to be the most satisfactorymethod of semen collection in the Boer goat.S. Afr. J. Anim. Sci.1983, 13: 2fi-252Semen is weekliks, deur die jaar, van drie Boerbokramme met behulp vandie kunsvagina en van twee Angora- en twee Boerbokramme deur middelvan eletriese stimulasie gekollekteer om seisoenale variasie insemenkwaliteit vas te stel. Die semeneienskappe volume, digtheid, persen-tasie lewende sperme, persentasie abnormale sperme, pH en motiliteit isgemonitor. Geen seisoenale verskille in semenkwaliteit is verkry nie. In dieBoerbok (kunsvagina) is 'n betekenisvolle (P-( 0,05)verskil tussen maandeverkry ten opsigte van die persentasie lewende sperme terwyl die volume(P< 0,01) en pH (P( 0,G5) van ejakulate betekenisvol aer was by rammewaar semen met behulp van die kunsvagina gekollekteer is en die digtheiden motiliteit van semen betekenisvol (P< 0,01) hodr is vergeleke metelektriese stimulasie. 'n Negatiewe korrelasie (-0,90) is ook verkry tussendie persentasie lewende sperme en persentasie abnormale sperme by Boer-bokramme wat met behulp van die kunsvagina gekollekteer is. DieAngorabokram het 'n ejakulaat met 'n betekenisvol hodr motiliteit (P< 0,01)en digtheid (P< 0,01) en laer volume (P< 0,O5) met elektriese stimulasie asdie Boerbok gelewer - 'n betekenisvolle (P< 0,01)variasie in pH tussenmaande is met hierdie metode van semenkolleksie verkry. Die bevindingehet die kunsvagina bewys as die geskikste metode van semenkolleksie bydie Boerbokram.S.-Afr. Tydskr. Veek.1983, 13: zfi-252Keyurords: Angora goat, Boer goat, collection techniques, semen qualityJ.P.C. Greyling* and J.A.N. GrobbelaarAnimal and Dairy Science Research Institute,Irene, 1675 Republic of South Africa*To whom correspondence should be addressed.Received ll November 1982IntroductionA low kidding rate is often only attributed to low fertility inthe doe, while the important contribution of the ram is oftenignored. The restricted breeding season of many small stockbreeds has led to attempts to alter the breeding season so thatoffspring can be produced during any season of the year.However, these studies concentrated on ewes or does and lit-tle information is given about the fertility of rams.Corteel (1978) postulated that the low fertility observed inthe middle of summer was linked principally to the quality ofthe sperm produced during that period and not to a drop infertility by the does. Periods of low sperm motility were con-temporaneous with the periods of low fertility, suggesting thatthe fertilizing capacity of goat spennatozoa becomes drasticallyreduced for some months each year during the non-breedingseason. Most researchers allege that semen production (andnot so much semen quality) is affected by seasonal changes(Colas & Brice, 1976; Colas & Courot, 1976). Shelton (1960)found a greater seasonal effect with the ram than with the doe.According to Courot (1976), sperrn motility and the percen-tage live sperm, determine the quality of the semen. The ob-ject of this trial was to evaluate the quality of Angora andBoer goat semen collected throughout the year by means ofartificial vagina and/or electrical stimulation, for the purposeof freezing semen and doing AI throughout the year.ProcedureSemen from five Boer and two Angora goat rams was col-lected at regular weekly intervals (October, 1980 to September,l98l) by means of the artificial vagina and/or electrical stimula-tion. From three of the Boer goat rams, semen was collectedby means of an artificial vagina while electrical stimulation wasused on the other two Boer goat rams and on the Angora rams.After collection, the following properties were evaluated:(r) The volume of the ejaculate was measured by collectingthe semen in a calibrated test-tube.(iD The colour of the ejaculate was noted as an indicationof the semen density and the possibility of semen contami-nation.(iii) The motility of the ejaculate was assessed microscopical-ly and a value (between 0 and 5) awarded according tothe motility of the semen. Simultaneously as estimationof the percentage of live sperm was made.(iv) Actual sperm counts were done using a hemocytometer(dilution rate of 1:200 was used) to calculate the densityof the ejaculate.(v) The percentage of live sperm was determined by meansS. Afr .  J .  Anim. Sci .  1983, l3(4)of a nigrosine eosine stain - this slide was then also usedfor the determination of the percentage of abnormalities.(vi) The pH of the semen was measured with a pH-meter assoon after the collection of the semen as possible.Daylight lengths and average monthly temperatures for theobservation period were obtained from the Weather Bureauat Irene, Pretoria. The method of semen collection (artificialvagina ys electrical stimulation), the breed of goat (Boer goatvs Angora) and the seasonal changes in semen quality (sum-mer - December to February y,s autumn - March to Mayvs winter June to August vs spring September toNovember) were compared in this experiment. The data wereanalysed by analyses of variance and the calculation ofcorrelations.ResultsArtificial vagina versus electrical stimulation i  the Boergoat ramThe annual macroscopic variation in semen production andmotility (mean + S.D.) obtained by the different techniquesof semen collection is set out in Table I and Figure 1. Theartificial vagina yielded significantly (P( 0,01) less semen byTime of  the year (Months)Figure I Semen production (volume) through the year in Boer and Angoragoat rams using the different collection techniques (artificial vagina (AV)and electrical stimulation (ES)).251volume (mean 1,56 vs 2,48mA and a hieher (P< 0,05) motilitycompared with the semen collected by the technique of elec-trical stimulation.No significant difference in pH (Table 2) between the variousmonths of the year was observed, but a significantly (P( 0,05)higher pH for semen collected by means of electrical stimula-tion was noted. The density (concentration) of the semen andthe percentage of live sperm were significantly (P( 0,01 andP< 0,05 respectively) higher in semen collected by means ofthe artificial vagina (see Figure 2). No significant differencewas found in the percentage of abnormalities for the differenttechniques of semen collection.Electrical stimulation - Angora versus Boer goat ramsThe volume of semen yielded (Table I and Figure l) in theTable 2 The effect of season on the pH of the semene jacu la tes  fo r  the  d i f fe r ren t  co l lec t ion  techn iquesin Boer  and Angora goatsElectr ical  s t imulat ionArtificialMean vagina Boerdaylight goatMonths length (h) pHBoer goat Angora goatpH pHcl e  o-c=i 2 eo2 ngE z,soJan.Feb.Mar.AprilMayJun.Jul.Aug.Sept.15,0013,7 513,4012,3012,NI1 ,50ll,'l512,1013,0013,5014,2514,5013,086,82 + 0,196,79 + 0,146,76+0,226,50+0,327,02+0,216,59+0,246,79 +0,236,93 + 0,106,61x.0,126,68 + 0,236,63 + 0,236,40+0,286,716,N-7,026,75 + 0,286,89 + 0,146,78+0,236,82+0,366,94+ 0,156,95 t 0, l86,96+0,217 ,19  +  0 ,1  56,94 t 0,186,72+0,206,93 +0,256,&+0,206,886,&- ' ,7 ,196,85 + 0,216,91+ 0,176, '75 + 0,176,74+0,346,95 + 0 ,146,84+0,176,93 + 0,187 ,00+0 ,137,02+0,346,59 + 0 ,116,84 t 0,406 ,51 t0 ,386,836,51-' . l ,02Oct.Nov.Dec.MeanRangeTable 1 The effect of season on semen production and motility lor the ditferent collection techniques inBoer and Angora goat ramsArtificial vaginaBoer goatElectrical stimulationBoer goat Angora goatMonthMeanmonthlyTemp. oCSemen volume(m0Motility( 1 - 5 )Semen volume(m0Motil ity( 1 - 5 )Semen volume Motil ity(mf) (l - 5)-  Day l igh t  leng th*  Boer  goat  a r t i f i c ia l  vag ina  - - -  Angora  goatES- JJan.  Feb.  Mar .  Apr .  May Jun.  Ju l .  Aug.  Sept .  Oct .  Nov .  Dec .Jan.Feb.Mar.Apr.MayJun.Jul .Aug.Sept.Oct.Nov.Dec.Mean20,819,017  , 416,612,49,410,418 ,71 5 , 319 ,318 ,319,916,461,54 a 0 ,781 ,52+0 ,73l , 3 l  +0 ,461 ,73  l 0 ,751,50 + 0 ,681,53 + 0 ,542,03 + l ,2 l1 ,60 + 0 ,301,20 + 0 ,301,56 + 0 ,84|  ,52 + 0 ,571 ,73  +0 ,511 ,562,77 + 0,933, '13 + 0 ,523,46x.0,783 ,42+  0 ,513,65 + 0 ,342,83 + 0 ,881,96+0,722,69 +0,462,75 + 1 ,062,04 + 0,993,38 + 0 ,833 ,14+0 ,822,993 ,56+  2 ,322,89 + 2,281,78 + 0 ,301,89 + 0 ,971,62 + 1 ,051 ,46+  0 ,592, '78x.1,601,50 + 0 ,672,40+ 1,023 , 0 5  +  l , l 73 ,05  +  1 ,353,82+2,012,492,29 + 0,992 , 1 3  x . 1 , 3 62 ,80  +  l , 0 l2 ,36+0,752 ,17  +0 ,821,65 + 0 ,711,75 + 0 ,851 ,75  +  1 ,082 ,31+  0 ,371,50 + 0 ,892,00 + 0,932,05 + 0,982,061,86 + 0 ,64I , 68  +  1 ,371 ,33  +0 ,431,54 + 0 ,781 ,83  +  0 ,851,46+ 0,461,87 + 1 ,001 ,75  +0 ,791,40 + 0 ,821,25 + 0 ,541 ,88  +  1 ,061,69 x .0 ,541 ,633 , 1 9 +  l , l 93,63 + 0 ,883,20+ 0,713 , 1 3 + 0 , 9 53,38 t 0,483,00 t 0,782,94+0, '182,42+ 1,662,06+ 1,243,69 +0,463 , 1 3  t  1 , 3 03,45 + 0 ,863 , 1 02521 , 0J a n . Feb.  Mar .  Apr .  May Jun.  Ju l .  Aug.  Sept .  Oct .  Nov .  Dec .T ime o f  the  year  (Months)Figure 2 Semen density (concentration) through the year in Boer andAngora goat rams using different techniques (artif icial vagina (AV) andelectrical stimulation (ES)).Angora by electrical stimulation was significantly (P( 0,05)lower (1,63 m/ v,s 2,48 m$ with a higher (P< 0,01) motility(3,1 vs 2,M) when compared to that of the Boer goat. Nosignificant difference in pH between the two breeds was ob-tained, but a significant (P< 0,01) difference between monthswas obtained (Table 2). The Angora produced an ejaculatewith a higher (P< 0,01) sperm density (Figure 2) andpercen-tage of live sperm (Figure 3), with no significant differencein the percentage of abnormalities between the breeds.85 -  Angora goat -- -  Boer goat3530Jan .  Feb .  Mar .  Apr .  May  Jun .  Ju l . Aug. Sept. Oct. Nov. Dec.Time of  the year (Months)Figure 3 Seasonal variation in the percentage of live sperm per ejaculatein Boer and Angora rams collected by means of electrical stimulation.DicussionNo seasonal variation in semen concentration and sperm pro-duction indicated by the volume of the ejaculate was recorded.This is in agreement with work done by Loubser (1980) onthe Angora rzlm. Semen motility tended to be lower from Juneto October for the Boer goat and June to September for theAngora goat, while sperrn density declined to a minimum valuein November for Boer goat rams (both collection techniques)and in June for Angora goat rams. A negative correlation( - 0,90) was obtained (Figure 4) between the percentage oflive sperm and the percentage of abnormal sperm in the Boergoat ram when the artificial vagina was used. It is of interestto note that, although non-signif,rcant, the positive correlation(0,65) between the percentage of abnormal sperm and daylightlength as well as the percentage of abnormal sperm andtemperature (0,61) in the same group. The percentage of ab-normalities per ejaculate, with which lowered fertility isassociated, stayed relatively low throughout the observationS.-Afr. Tydskr. Veek. 1983, l3(4)Jan. Feb.  Mar.  Apr.  May Jun.  Jul .  Aug. Sept.  Oct .  Nov.  Dec.Time of  the year (Months)Figure 4 The effect of season on the percentage of live and abnormalsperm per ejaculation in Boer goat rams collected by means of the ar-tif icial vagina.period and never exceeded 2090 (Foote,1974).The most acidic pH of the semen was noted during Decem-ber for both breeds. A negative correlation ( - 0,79) was foundin the Angora goat ram between pH and the percentage oflive sperm in the ejaculate - this is in agreement with Chahal,Rattan & Parshad (1979).In the Boer goat ram the percentage of live sperm yieldedby the technique of the artificial vagina was significantly (P-<0,05) higher than that of semen collected by the technique ofelectrical stimulation. A significant (P< 0,05) difference be-tween months was also found in the percentage of live spermin the artificial vagina group, with the lowest values recordedin the months of October and January. This should be takeninto consideration when semen is collected for the purpose ofartificial insemination or storage by the technique of deepfreezing.The quality of the semen collected by the technique of elec-trical stimulation from the Angora goat ram proved to be ofa higher quality than that produced by the Boer goat in thesame group.As in sheep (Hulet, Foote & Blackwell, 1964) the artificialvagina technique of semen collection in the goat once againproved to be the most desirable technique, but the final andmost important criterion for the evaluation of semen qualityand freezability lies in the fertilizing capacity of the semen.ReferencesCHAHAL, A.S., RATTAN, P.J.S. & PARSHAD, O., 1979. SOMCphysico-chemical studies on semen and their interrelationship duringdifferent seasons in Coniedale rams. Ind. J. Anim. Sci. 49(Q, 433.COLAS, G. & BRICE, G., 1976. Seasonal variations of the fertilizingcapacity of deepfrozen ram semen. Proc. VIIIth Int. Congr. Anim.Prod. ond A.I. Craww.COLAS, G. & COUROT, M., 1976. Storage of ram semen. Proc. Int.Sh. Br. Congr. Muresk.CORTEEL, J.M., 1978. Seasonal variations in motility and fertilizingability of goat spermatozoa. Anim. Breed. Abstr. M, 41.COUROT, M., ln6. Semen quality and quantity in the ram. Proc. Int.Sh. Br. Congr. Muresk.FOOTE, R.H., 1974. Artificial insemination. In: Reproduction in farmanimals. Ed. Hafez E.S.E., Lea and Febiger, Philadelphia, p.4D.HULET, C.V., FOOTE, W.C. & BLACKWELL, R.L., 1964. Effect ofnatural and electrical ejaculation on predicting fertility in the ram. "/.Anim. Sci. 23. 418.LOUBSER, P.G., 1981. Die seisoenale veranderinge in geslagsaktiwiteit ensemenkwaliteit by die Angoraram en die diepvriesing vanAngoraboksemen. M.Sc (Agrrc.) thesis, University of Stellenbosch.SHELTON, M., 1960. Influence of the presence of a male goat on theinitiation of oestrous cycling and evaluation of Angora does. J. Anim.Sci. 19. 368.- Mean monthly temperature* Boer goat AV- Boer goat ES--- Angora goat ESE2 0 bti)(U1 5 Ec(Et v o(!s Bq)&8075E 7 0o),t 659 6 03' 55€ s oo9 4 5oL 4 015 e-0)r ^  Er v  0 )F4,0=:  3,5cE 3'02,5Xi  2,0oE  1 , bE 7 58_ 70ao 6 5; 6 0E' s59 5 08 4 s40- Percentage l ive sperm ---Percentage abnormal sperm

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Seasonal variation in semen quality of Boer and Angora goat rams using different collection techniques

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Seasonal variation in semen quality of Boer and Angora goat rams using different collection techniques

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