|| Home || Search || Contact || Publications Eshop || Privacy Statement ||
|| Home || Search || Contact || Publications Eshop || Privacy Statement ||
Summary of full report
November 2003
RIRDC Publication No 03/104 RIRDC Project No AAI-1A
The primary aim of the studies in this report was to develop the technology for artificial insemination in alpacas in association with acceptable pregnancy rates following AI. The project was broken down into 5 steps to achieve this aim: Consistent and reliable collection of semen, characterisation of semen to allow selection of suitable ejaculates for preservation, chilling of alpaca semen, freezing of alpaca semen and artificial insemination of females.
Artificial insemination (AI) in alpacas is the subject of research in several countries. First attempts at AI occurred in the 1960s in SAC in Peru (Fernandez-Baca et al. 1966, Calderon et al. 1968) and camels (Elliot 1961). Since then, studies in semen collection and artificial insemination have been performed in alpacas and other South American camelids in Australia (Gunn 1999), North and South America (Bravo et al. 1997, Ratto et al. 1999b, Huanca et al. 2001b), Britain (McEvoy et al. 1992b) and Germany (Burgel et al. 1999). Concentrated efforts at AI in camels have occurred in the last 20 years in an attempt to improve quality and production of milk and meat, in response to higher stakes in camel racing and increased interest in breed conservation (Purohit 1999a).
The reproductive physiology of alpacas differs to that of other domestic animals and remains poorly understood. Males mate in sternal recumbency for approximately 20 minutes and ejaculate many times during this period (Lichtenwalner et al. 1996a, 1996b). Each ejaculate consists of low volume, high viscosity semen containing a low sperm concentration (Sumar 1983, McEvoy et al. 1994). The fertility of alpaca males declines with increasing numbers of consecutive matings (Bravo et al. 1997b).
Gestation length is about 11.5 months, twins are rare and males reach puberty from 1 to 3 years of age (Bravo 1994). Generation intervals are relatively long because males are slow to sexually mature and females exhibit an extended gestation, so conventional breeding results in slower genetic gain in comparison to other fibre-producing domestic species such as sheep and goats.
Development of artificial insemination is aimed at increasing the use of superior alpaca males as multiple doses of semen will be derived from each ejaculate. Artificial insemination will reduce the need for ‘mobile matings’ and therefore reduce the risk of injury and transport-associated diseases in elite alpaca males and significantly reduce the risk transmission of Johne’s disease, lice and other infectious agents among alpaca farms. Artificial insemination will also allow more humane and economic importation of superior genotypes from overseas and increase the efficiency of dissemination of superior alpaca genotypes around Australia. In other fibre industries, such as Merino sheep and Angora goat production, assisted breeding is being used to improve fibre quality more rapidly than would otherwise be possible by natural mating.
There are no established AI services world-wide. The reasons include the difficulties of funding and sustaining research in Latin America in the past, the difficulty in semen collection, the mucoid characteristic of alpaca semen which precludes the easy adaptation of AI technology from other species, the characteristic of induced ovulation in female alpacas, the lack of techniques to define reproductive excellence in male alpacas, the lack of proven techniques to store alpaca semen in chilled or frozen form and the difficulty of transcervical pipette passage of some females This report presents new data on the techniques used for the collection, characterisation, preservation and insemination of alpaca semen. Consistent and reliable collection of alpaca semen was possible using a wooden mannequin covered with a tanned alpaca hide and fitted with an artificial vagina. It was possible to train both virgin and experienced alpaca males to mate with the mannequin.
Components of mating behaviour were defined during the training of males and during semen collection and characteristics of semen that define an ejaculate were established. One of the most important observations made during the study was that semen quality varied considerably within and between males.
Numerous diluents were mixed with semen in an attempt to prolong the life and maintain the health of sperm following collection in the artificial vagina. Extenders containing egg yolk and glycerol, and in particular Triladyl® (Minitub, Germany), proved the most effective extenders for chilled semen up to 48 hours. Immediate post-thaw activity of sperm was approximately 20 to 40 % when either the Green/Clear camel buffer (IMV International Corporation, USA) or Biladyl A/B (Minitub, Germany) was used as extender for freezing semen.
Transcervical deposition of semen into the tip of the uterine horn ipsilateral to the ovary bearing the dominant follicle proved to be a simple and efficient technique for artificial insemination. No pregnancies were achieved using transcervical, intrauterine AI of chilled or frozen-thawed semen.
The findings in this project provide a sound basis on which to continue developing the technology for collection, preservation and insemination of alpaca semen. Although AI was first attempted in the 1960s in South American camelids, the small numbers of pregnancies that have been achieved using chilled or frozen semen since then reflect the difficulties of transferring artificial breeding technology from other domestic livestock to camelids. The physiological idiosyncrasies of male alpacas such as extended mating duration and low volume, low density, high viscosity semen in combination with the variation in quality of ejaculates both within and between males provided challenges throughout the entire project.
Data collected during the project will assist breeders and veterinarians in the Australian alpaca industry to select sound sires through evaluation of breeding behaviour and semen characteristics. It is anticipated that this same information will assist with the selection of males with semen that is suitable for chilling and/or freezing. Semen characteristics need to be further defined in relation to age, season and nutritional status and testicular size.
The knowledge gained about
collection, characterisation, preservation and insemination of alpaca semen
will hasten the availability of artificial insemination services in alpacas.
This will benefit the Australian alpaca industry with more efficient utilisation
of genetically superior males and faster dissemination of improved genotypes
throughout the national herd.
|
