Reproduction in Domestic Animals

70 HJ Bertschinger, DGA Meltzer and A van DykTable 1. Summary characteristics of fresh cheetah semen samples(n = 160)pHVolume(ml)% Livesperm% Sperm withlinear motilitySpermcount · 10 6 ⁄ ml% NormalspermRange 6.4–8.0 0.3–2.1 10–95 8–90 1–211 0–86Mean 0.7 65.2 58.1 32.7 40.3SD 0.5 18.5 18.6 36.13 17.5Table 2 lists the more common sperm defects ofcheetahs. Abnormal heads, knobbed acrosomes(Fig. 7e, f), mid-piece and flagellar defects were themost common morphological abnormalities of cheetahsperm. It is accepted that a normal population ofcheetah sperm may vary moderately as far as head size isconcerned (pleiomorphism; Wildt et al. 1983, 1987).Compared to the sperm of species such as bulls, ramsand boars, cheetah sperm heads are very small and notas flat (Fig. 7b,c). Orientation on the slide probablyexacerbates the pleiomorphic appearance. Flagellardefects, (Fig. 7d,h,i), depending on their incidence, hada marked affect on linear sperm motility and generallyspeaking good motility was associated with at least fairmorphology. Where testicular function was severelyimpaired, the incidence of spermatogenic cells was oftenincreased (Fig. 7j).Figure 8 shows the relationship between sperm morphologyand number of litters born at de Wildt(Bertschinger and Meltzer 1998). As the % normalsperm increased so did the number of litters. As can beexpected, compared to % normal sperm, an inverserelationship between % major sperm defects and littersborn was seen. The low number of births on the lefthandside for % major defects and on the right for %normal sperm reflects the small numbers of male cheetahwith good sperm morphology. Approximately 30% ofall males tested fell into the ‘poor’ category (see below).Semen quality of wild-caught males appeared to be nobetter than that of captive-bred animals. Outbred freerangingsouthern African lions and leopards, by comparison,display good sperm morphology and the sizeand shape of sperm heads, which are flatter, areconsistent (Fig. 7k).During the period 1998–2007, 113 semen examinationswere carried out. The number and percentage ofmales falling into the ‘good’, ‘fair’ and ‘poor’ categorieswere 41 (36.3%), 27 (23.9%) and 45 (39.8%), respectively.Twenty-six males were examined over 2 years ormore during the period of 1998–2006. Of these, nineshowed an improvement by one or more categories, nineremained the same and seven showed a decrease insemen quality. Deterioration was often associated withdiseases such as gastritis. We analysed the litter datafrom 1999 to 2007 (excluding 2002) in terms of spermmorphology categories we use at de Wildt. The numberof litters produced and average litter sizes for categories‘good’, ‘fair’ and ‘poor’ males were 21 and 3.44, 18 and3.14 and 18 and 2.28, respectively. The differences inlitter size were not significant (p = 0.1449; Kruskall–Wallis test).DiscussionThe breeding results achieved at de Wildt over the last31 years prove that cheetah can be bred successfully incaptivity. The success, however, is dependent on thecorrect housing, day to day management and breedingmanagement. Other centres such as the Cheetah Projectat Kapama and the Wassenaar Wildlife Breeding Centrein The Netherlands have also bred captive cheetahssuccessfully. The breeding strategy at Wassenaar, whichhas resulted in 210 cubs born from 62 litters, is worthdescribing as it differs a little from the one practiced atde Wildt. Briefly, male and female utilize the same campin turns which means that they pick up the scents of theopposite sex (Beekman et al. 1997; Louwman andLouwman 2005). The behaviour of the cheetahs isobserved carefully and once the male and female showintense interest in the scents left behind contact throughthe fence of adjoining enclosures is allowed. When thefemale displays signs of oestrus she is given access to themale enclosure and left with him for approximately 48 hduring which two to five matings occur.From our earlier work (Meltzer 1987; Bertschingerand Meltzer 1998) a relationship was seen betweensperm morphology and number of litters born at deWildt. Despite poor semen quality, we showed morerecently (1999–2007) that some males are capable ofproducing litters albeit with a smaller average litter size(2.28 vs 3.14 and 3.44). A number of factors, however,may affect semen quality. Semen collected by means ofelectro-stimulation does not necessarily reflect the truepotential of a particular male. Firstly, urine contaminationaffects especially motility but maybe even tailHead defects Mid-piece defects Tail defectsTable 2. Common defects of cheetahspermKnobbed ⁄ lipped acrosome Aplasia of mitochondrial helix Mid-piece reflexLoose acrosome a Pseudodroplet Bent mid-pieceMacrocephalic with single or double tail Stump-tail Coiled tail – coiled belowor on top of the headMicrocephalicProximal dropletImmature headDistal dropletDegenerated or vacuolated headFree tail forms with aplasiaof the mitochondrial helix bPyriformDeformed headsLoose heada This defect, if the sperm is otherwise normal, was not added to the % abnormal sperm.b This defect should merely be noted and not added to the % abnormal sperm. It arises during meiosis and is associatedwith macrocephalic heads in the ejaculate.Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag