Reproduction in Female Wild Guinea-Pigs

Rood, Jon P.; Weir, Barbara J.

doi:10.1530/jrf.0.0230393

Cited by 80 publications

(59 citation statements)

References 7 publications

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“…In" fact, guineapigs appear to exhibit a strong herd of family behaviour which is supported by observations of feral animals (Rood, 1970;Rood, 1972). This need for close group association contrasts sharply with the aggressive territorial behaviour of other rodents.…”

Section: Introductionmentioning

confidence: 60%

Use of cage space by guineapigs

1989

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SummaryCage space requirements for laboratory animals have been established by Government Regulation and Recommendations. In order to test the adequacy of these space allocations, the use of cage floor area by breeding groups of guineapigs was studied. A computer-coupled video tracking system capable of imaging in low light intensity as well as total darkness was used to determine the average per cent occupancy by guineapigs in all portions of a cage over 12-h light and dark cycles. Simultaneous time synchronized slow motion video recordings permitted an analysis of activity to be coordinated with cage use data. Results of the study revealed that breeding groups of guinea pigs utilize the periphery of the cage almost to the total exclusion of the centre of the cage. Approximately 75-85070 of all occupancy in both the day and evening hours occurred in 47070 of the cage floor area located along the periphery. Analysis of video recordings revealed that the animals remained active throughout the day and night with no prolonged period of quiescence that could be associated with sleep. Results of this study suggest that while guidelines for housing guineapigs based on area allocation per animal can be formulated and are easy to administer, they cannot be supported by the behavioural characteristics of these animals or careful quantitation of their pattern of cage space utilization.

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Section: Introductionmentioning

confidence: 60%

Use of cage space by guineapigs

1989

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“…This membrane has been recorded in all hystricomorphs studied so far, except the coypu, Myocastor coypus (Weir, 1974). Rowlands & Weir (1977) regarded the perforation of this membrane as an 'external indicator of ovulation' and synchronization of perforation with regular surges of oestradiol-17ß concentrations in peripheral blood in the porcupine confirmed this (Rood & Weir, 1970;Weir, 1973a) and behavioural as well as pheromonal mechanisms may be involved in initiating cyclic ovarian activity in porcupines. Gestation lengths reported here (93-94 days) were accurately measured since they were based on calculations of the interval between observed matings and normal parturition with pregnant females isolated from fertile males during that interval.…”

Section: Lactationmentioning

confidence: 79%

“…Lactation anoestrus is not unusual for hystricomorph rodents and occurs in the chinchilla (Weir, 1973b), the wild guinea-pig (Rood & Weir, 1970), green acouchi (Weir, 1971a) and plains viscacha (Weir, 1971b).…”

Section: Lactationmentioning

confidence: 99%

Reproduction in captive female Cape porcupines (Hystrix africaeaustralis)

Aarde¹

1985

Reproduction

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Summary. Captive females attained sexual maturity at an age of 9\p=n-\16months and conceived for the first time when 10\p=n-\25months old. Adult females were polyoestrous but did not cycle while lactating or when isolated from males. The length of the cycle varied from 17 to 42 days (mean \ m=+-\ s.d. 31\m=.\2\ m=+-\6\m=.\5 days; n = 43) and females experienced 3\p=n-\7 sterile cycles before conceiving. Pregnancy lasted for 93\p=n-\94days (93\m=.\5\ m=+-\0\m=.\6days; N = 4) and litter intervals varied from 296 to 500 days (385 \ m=+-\60\m=.\4; n = 10). Litter size varied from 1 to 3 (1\m=.\5\ m=+-\ 0\m=.\66; n = 165) and the well-developed precocial young weighed 300\p=n-\400 g (351 \ m=+-\ 47\m=.\4 g; n= 19) at birth. Captive females reproduced throughout the year with most litters (78\m=.\7%; n = 165) being produced between August and March.

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“…Subsequent studies on the reproduction of this species have been almost exclusively directed towards the female and have resulted in the establishment of the length of the oestrous cycle, gestation period and the effects of season on breeding performance (Rood & Weir, 1970). Weir (1971) also found that the occurrence of the oestrous cycle could be influenced by the presence of a male.…”

Section: Discussionmentioning

confidence: 99%

Postnatal development of the testes in the cuis, Galea musteloides

Holt

1977

Lab Anim

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SummaryTesticular development to 9 months of age has been studied. Seminiferous tubule diameter increased in a linear manner between 13 and 65 days of age, and there was a steep increase in testicular weight with age. At about 9 months the animals weighed 400-500 g and total testicular weight was about 10 g. This relatively large testicular size was correlated with high sperm density in the semen.Spermatogenesis commenced at about 21-25 days of age, when the first spermatids were found. Spermatozoa appeared in a small proportion of seminiferous tubules by 31-35 days of age, and were seen in the epididymides of an animal of 31 and another of 34 days. Epididymal spermatozoa were consistently present in large numbers after 60 days and this correlated with the increased frequency of mature seminiferous tubules.Leydig cell size increased rapidly from 13 to about 60 days, then remained constant. Inferences have been drawn from this and the study of spermatogenesis about the level of testosterone secretion.The results indicate that the male cuis is almost fully grown and sexually mature by about 90 days of age.The cuis, Galea musteloides, a hystricomorph rodent bearing some similarities to the laboratory guineapig, was introduced as a laboratory animal by Weir (1970), who described techniques of management and breeding. Subsequent studies on the reproduction of this species have been almost exclusively directed towards the female and have resulted in the establishment of the length of the oestrous cycle, gestation period and the effects of season on breeding performance (Rood & Weir, 1970). Weir (1971) also found that the occurrence of the oestrous cycle could be influenced by the presence of a male. No systematic studies of the male cuis have yet been carried out, so that information is lacking on such basic matters as the age at which puberty occurs and full sexual maturity is reached. The present investigation of postnatal testicular development has been undertaken to remedy this situation. Data have been collected on the changes with age in body and testicular weights, seminiferous tubule diameter and Leydig cell size in young cuis. These parameters are correlated with the onset of spermatogenesis, determined by a quantitative analysis of cell associations in the seminiferous tubules and observation of the presence of spermatozoa in the epididymis. Materials and methodsA total of 109 male cuis aged from 13 days to 9 months, taken from the Wellcome Institute breeding colony, was killed at intervals over a period of 3 years. An uninterrupted series was obtained between 13 and 65 days, but it was not possible to extend this continuously to an age much beyond that of full sexual maturity. However, a group of 8 animals of 89-94 days, and another of 6 animals aged about 8-9 months, were obtained. After death, the animals were weighed. The testes and epididymides were removed, fixed in Bouin's fluid for 24 hours (an incision being made after 1 hour), and then transferred to 70% alcohol. The epididymides were separated and...

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Reproduction in Female Wild Guinea-Pigs

Cited by 80 publications

References 7 publications

Use of cage space by guineapigs

Use of cage space by guineapigs

Reproduction in captive female Cape porcupines (Hystrix africaeaustralis)

Postnatal development of the testes in the cuis, Galea musteloides

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