Standardising bull breeding soundness evaluations and reporting in Australia

There is substantial variation in bull breeding soundness evaluation procedures and reports in Australia; the situation is compounded by difficulties in interpretation and the validity of many reports. In an effort to overcome this, the scientific literature was reviewed [Fordyce G. In: Fordyce G, editor. Bull fertility: selection and management in Australia. Eight Mile Plains, Australia: Australian Cattle Vets; 2002] and the needs of stakeholders were considered in preparing a manual, Evaluating and Reporting Bull Fertility [Entwistle KW, Fordyce G. Evaluating and reporting bull fertility. Eight Mile Plains, Australia: Australian Cattle Vets; 2003.] that outlined standards for assessing and reporting bull breeding soundness. A new recording and reporting system, called Bull Reporter, is based on standards from this manual and groups bull fertility traits into five summary categories: Scrotum, Physical, Crush-side Semen, Sperm Morphology, and Serving. The client will generally select which categories they wish to have included in the evaluation to suit their specific purposes. While there is adequate room for comments, the veterinarian is not required to make an overall judgment of whether the bull has normal capacity to sire calves under natural mating management, but ensures the standards for each selected category are met. Professional, standardised, easy-to-read reports are produced either electronically [Entwistle KW, Fordyce G. Evaluating and reporting bull fertility. Eight Mile Plains, Australia: Australian Cattle Vets; 2003.] or manually. A bull owner or their agent signs the certificate to affirm that bulls have not undergone procedures to rectify faults which may have otherwise caused them to fail the standards. An accreditation system for assessing sperm morphology was established because of its demonstrated relationship with pregnancy rates and because of the difficulties in achieving consistent and accurate assessments among laboratories. It is considered that Bull Reporter is applicable to beef and dairy bulls across all levels of management, genotypes and environments throughout Australia, with substantial potential for application elsewhere in the world. Crown Copyright (c) 2006 Published by Elsevier Inc. All rights reserved.

Inheritance of proportionate dwarfism in Angus cattle

Objective To determine the mode of inheritance of congenital proportionate dwarfism in Angus and Angus crossbred cattle, initially detected in two commercial beef herds in northern New South Wales. Design Matings of normal carrier sires to unrelated cows of diverse breeds, and of one carrier sire to his unaffected daughters. An unrelated Piedmontese bull was also mated to unaffected daughters of the carrier sires. Procedure Two carrier Angus bulls and nine unaffected daughters, all of whom were completely indistinguishable from normal animals, were purchased for controlled breeding studies under known nutritional and disease conditions. Affected and carrier individuals were examined for the presence of obvious chromosomal abnormalities. Results Angus dwarfism has been successfully reproduced under controlled experimental conditions over successive years using unrelated dams and is undoubtedly heritable. The high frequency of occurrence of affected individuals (23/61 = 0.38 +/- .06) among the progeny of matings of the Angus sires to unrelated females of diverse breeding is not compatible with recessive inheritance, because of the negligible frequency of proportionate dwarfism in the breeds of the dams. Both paternal and maternal transmission of the defect was demonstrated, so that imprinting in the strict sense of a gene that is only expressed when received from the male parent appears not to be involved. Tested individuals showed no evidence of gross chromosomal abnormality. Dominant autosomal inheritance with incomplete penetrance was indicated by the lack of expression of the defective gene in the two Angus sires and in three unaffected daughters who produced dwarf calves from matings to the Piedmontese bull. Conclusions The mode of inheritance is that of a single autosomal dominant gene with a penetrance coefficient of 0.75 +/- 0.12, estimated from the observed incidence of 23/61 affected offspring of the two carrier Angus bulls mated to unrelated dams. Simple genetic models involving either (i) an unstable mutant which changes at high frequency to the expressed dominant dwarfing allele during gametogenesis, or (ii) a dominant allele with penetrance determined by an unlinked modifying locus, are shown to be compatible with the experimental data. Both models indicate that penetrance of the dwarfing gene may possibly be higher in matings involving carrier daughters of the two Angus bulls.

Genetic parameters and predicted response to selection for lean growth in an Australian commercial nucleus pig herd

Genetic parameters for performance traits in a pig population were estimated using a multi-trait derivative-free REML algorithm. The 2590 total data included 922 restrictively fed male and 1668 ad libitum fed female records. Estimates of heritability (standard error in parentheses) were 0.25 (0.03), 0.15 (0.03), and 0.30 (0.05) for lifetime daily gain, test daily gain, and P2-fat depth in males, respectively; and 0.27 (0.04) and 0.38 (0.05) for average daily gain and P2-fat depth in females, respectively. The genetic correlation between P2-fat depth and test daily gain in males was -0.17 (0.06) and between P2-fat and lifetime average daily gain in females 0.44 (0.09). Genetic correlations between sexes were 0.71 (0.11) for average daily gain and -0.30 (0.10) for P2-fat depth. Genetic response per standard deviation of selection on an index combining all traits was predicted at $AU120 per sow per year. Responses in daily gain and backfat were expected to be higher when using only male selection than when using only female selection. Selection for growth rate in males will improve growth rate and carcass leanness simultaneously.

Successful artificial insemination (AI) in the koala using neat and extended semen collected by electroejaculation (EE)

Presently AI in the koala has been based on the insemination of fresh undiluted semen collected with an artificial vagina (1). While this approach has been extremely successful, further refinement and implementation of AI for use with cryopreserved semen will require protocols that incorporate diluted semen collected by EE. Recent studies have shown that koala semen is likely to have an "ovulation factor" such that over-dilution may result in ovulation failure (2). The current study determined whether AI of EEed neat and/or diluted semen was capable of inducing a luteal phase and/or resulted in the production of pouch young. All koalas were inseminated in the breeding season between day 2 and 5 of oestrus and subsequently monitored for evidence of parturition (day 35) and return of oestrus. Successful induction of a luteal phase was based on evidence of an elevated progesterone concentration 28 days after insemination (2). All semen samples were collected by EE and seminal characteristics recorded (3). The diluent used for semen extension was Tris-citrate glucose (TCG) which contained antibiotics but no egg yolk (4). AI was conducted on conscious koalas using a "Cook koala insemination catheter" and a glass rod used to mimic penile thrusting (1). Three insemination treatments were used; (A) 1mL of undiluted semen (n = 9); (B) 2mL of 1:1 diluted semen (n = 9); and (C) 1 mL of 1:1 diluted semen (n = 9). The results of the AI trial are shown in Table 1. This study has shown that it is possible to use both neat and diluted semen (1:1; 1 or 2 mL) to successfully produce koala offspring at conception rates similar to those achieved following natural mating. Interestingly, dilution of semen had no apparent detrimental effect on induction of a luteal phase following AI.

Australian microhylid frogs (Cophixalus and Austrochaperina): phylogeny, taxonomy, calls, distributions and breeding biology

Despite a considerable surge in herpetological research in Australia over the last couple of decades the Australian microhylid frogs (Cophixalus and Austrochaperina) remain relatively poorly known. Herein I present the results of extensive fieldwork and molecular, morphological and call analysis with the aim of resolving taxonomy, call variation and distributions, and increasing our understanding of breeding biology. Analysis of 943 base pairs of mitochondrial 16S rRNA and 12S rRNA provides a well supported phylogeny that is largely consistent with current taxonomy. Levels of divergence between species are substantial and significant phylogeographic structuring is evident in C. ornatus, C. neglectus and C. aenigma, sp. nov. The description of C. concinnus was based on a mixed collection of two species from Thornton Peak and a new species is described to resolve this. C. aenigma, sp. nov., is described from high-elevation (>750 m) rainforest across the Carbine, Thornton, Finnigan and Bakers Blue Mountain uplands, north-east Queensland. C. concinnus is redescribed as a highly distinct species restricted to rainforest and boulder fields at the summit of Thornton Peak (>1100 m). Despite protection in Daintree National Park in the Wet Tropics World Heritage Area, predictions of the impact of global warming suggest C. concinnus to be of very high conservation concern ( Critically Endangered, IUCN criteria). The mating call of two species ( C. mcdonaldi and C. exiguus) is described for the first time and high levels of call variation within C. ornatus, C. neglectus, C. hosmeri, C. aenigma and Austrochaperina fryi are presented. Such variation is often attributable to genetically divergent lineages, altitudinal variation and courtship; however, in some instances ( particularly within C. hosmeri) the source or function of highly distinct calls at a site remains obscure. Molecular, morphological and call analyses allow the clarification of species distributions, especially in the northern mountains of the Wet Tropics. Notes are presented on the breeding biology of C. aenigma, C. bombiens, C. concinnus, C. exiguus, C. infacetus, C. mcdonaldi, C. monticola, C. neglectus, C. ornatus and C. saxatilis, which are largely consistent with previous accounts: small terrestrial clutches usually attended by a male. Courtship behaviour in C. ornatus is described and the first records of multiple clutching in Australian microhylids are presented (for C. ornatus and C. infacetus).