Natural and induced ovulation rate in prolific and non-prolific breeds of sheep in Ireland, Morocco and New Zealand

Ovulation rate, in mixed-age groups of prolific and non-prolific ewe breed types, after administration of a range of doses of PMSG (0, 375, 750 and 1500 i.u.) during the follicular phase of the oestrous cycle, were compared in Ireland, Morocco and New Zealand. The ewes in Ireland and Morocco were from the Finnish Landrace and Galway, and D'Man and Timhadite breeds, respectively. In New Zealand Booroola Merino x Romney ewes which had been previously identified as heterozygous carriers (F+) of the Booroola high fecundity gene and purebred Romneys were used to represent the prolific and non-prolific genotypes respectively; in addition a group of Booroola Merino x Romney non-carriers (++) of the major gene were also included for comparison. Ovulation rate at the oestrus which preceded stimulation with PMSG was also measured in all animals. In all 3 locations the ewes of the prolific genotype had a greater ovulation rate after PMSG stimulation than did the non-prolific controls. However, this association between prolificacy and response to PMSG was removed when ovulation rate after PMSG was transformed by dividing by the ovulation rate observed before PMSG administration. Despite the differences in the genetic basis of their high prolificacy the pattern of response to PMSG over the range of dosages used was similar in Finnish Landrace, D'Man and Booroola Merino x Romney (F+) ewes and all breeds had means of about 10 ovulations in response to 1500 i.u. PMSG. Amongst the non-prolific breeds, the Timhadite was the most responsive to PMSG although it had the lowest natural ovulation rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pigmentation in Black-boned sheep (<Emphasis Type="Italic">Ovis aries</Emphasis>): association with polymorphism of the <Emphasis Type="Italic">Tyrosinase</Emphasis> gene

Measurements were made in Black-boned (n = 40) and normal (n = 23) sheep (Ovis aries) from a flock in Nanping County of Yunnan Province, China, as well as a group (n = 21) of Romney Marsh sheep (O. aries) with the view to explaining the basis of the dark pigmentation occurring in the Black-boned animals. Plasma colour was significantly darker (P < 0.01) in Black-boned sheep than in their normal flock mates, which in turn had significantly darker plasma (P < 0.01) than the Romney Marsh sheep. Similar significant (P < 0.01) differences were measured for plasma tyrosinase activity and both groups of sheep from Nanping County had similar plasma concentrations of glutathione which were significantly smaller (P < 0.01) than for the Romney Marsh sheep.A partial fragment of 750 bp of exon 1 of the gene encoding tyrosinase was constructed and found to contain two silent mutation sites (G192C and C462T) but there was no effect on amino acid sequences of tyrosinase. Using restriction fragment length polymorphism analyses two allelic variants of site G192C were identified giving rise to the genotypes GG, GC and CC; the frequencies of allele G being 0.914, 0.824 and 0.286 in the Black-boned sheep, their flock mates and the Romney Marsh sheep respectively. Plasma tyrosinase activity was similar for genotypes GG and GC and for both genotypes significantly higher (P < 0.05) than for genotype CC. The sheep from Nanping County displayed only the GG and GC genotypes and had predominantly black or black and white coat colour whereas the Romney Marsh sheep were of either genotype GC or CC and exhibited only white coat colouration. It is not appears that the dark pigmentation of the Black-boned sheep arises because of polymorphisms in the exon 1 of tyrosinase gene. However, this result could explain the differences between Black-boned and Romney Marsh sheep but not for differences between Black-boned and Nanping Normal sheep. Moreover, this result has provided evidence of genetic markers in the form of polymorphisms of the tyrosinase gene which may help to find the black traits causing mutations. There would be merit in further studies using histochemical and molecular techniques to elucidate the causes of the dark pigmentation in these Black-boned sheep.     

The response of rams and ewes of three breeds to artificial photoperiod

Rams and ewes of the Romney Marsh (N = 6), Dorset Horn (N = 8) and Australian Merino (N = 8) breeds were subjected to 4 successive periods of alternating 6 h light/18 h dark ('short' days) and 18 h light/6 h dark ('long' days) preceded by 16 weeks of 12 h light/12 h dark. The initial period was of 32 weeks (16 weeks 'short' days; 16 weeks 'long' days) and the next 3 were of 24 weeks (12 weeks 'short' days; 12 weeks 'long' days). Rams of all breeds showed a cyclic pattern of growth and regression of testes associated with plasma testosterone concentration, influenced by the change in light regimen 15-19 weeks previously. Sexual behaviour was also cyclic but lagged by some 6-7 weeks. The changes were greatest in the Romneys and least in the Merinos in which a higher degree of sexual activity was evident even when the testes were regressed (P less than 0.001). This was the major breed difference. All ewes of the Romney and Dorset breeds showed marked seasonality related to the imposed light regimen, whereas only 1 of the 4 Merinos did so. The mean peak of ovarian activity in the former 2 breeds coincided with that of maximum sexual activity of rams housed with them; that is, some 6 weeks after maximum scrotal volume. The rams and ewes were subjected to serial blood sampling episodes for plasma LH and testosterone and tested for plasma LH release following GnRH administration. There was little variation between breeds in LH concentration. Testosterone concentration varied greatly in the ram, highest levels associated with the developed phase of the testes and with maximum LH pulse frequency. The LH response to GnRH changed with respect to the state of the gonads. Maximal responses were observed in the developing phase of testicular growth although this variation was greater in the Romney and Dorsets than in the Merinos (P less than 0.001). In the ewes, maximal responses were seen in the follicular phase (P less than 0.001), with no difference between the luteal and acyclic phases. There were no breed differences. Plasma pooled from the serial blood sampling episodes was assayed for prolactin.(ABSTRACT TRUNCATED AT 400 WORDS)     

Genetic control of lactate dehydrogenase gene A expression in sheep erythrocytes]

Polymorphism for the phenotypical expression of gene for LDH subunit A was demonstrated in sheep erythrocytes by means of starch gel electrophoresis. Three types of LDH were established differing in the relative activities of the second and third LDH isozymes. Familial analysis has shown that high level of LDH-2 and LDH-3 activities are determined by the autosomal gene Ldr-1a and low level of their activities is controlled by gene Ldr-1b. The frequencies of gene Ldr-1a in Altai thin-fleece, Romney Marsh and Linkoln breeds were 0,533; 0,509 and 0,425 respectively. Gene frequencies were also determined in crossbreeds. Possible mechanisms of the action of genes Ldr-1a and Ldr-1b in sheep erythrocytes are discussed.     

Food consumption and faecal deposition of plant nutrients by black swans (Cygnus atratus Latham) in a shallow New Zealand lake

Deposition of faeces by black swans (Cygnus atratus Latham) feeding on benthic algae in a shallow New Zealand lake was determined by collection of faeces from the lake bottom and from the shore. The two methods showed good agreement after adjustment for the weight loss on immersion. The mean daily faecal output per swan was 52 g dry weight. The nitrogen content of the faeces averaged 2.3% of dry weight, and was dominated by soluble organic nitrogen (59% of total N). Phosphorus averaged 0.44% of dry weight, with 66% of it being particulate, and 30% soluble reactive phosphorus. Although faecal inputs of total phosphorus were sufficient to generate concentrations of 15–30 mg m^–3, the faecal contributions of both N and P were only a minor component of the fluctuations observed in the lake, and were also small in relation to the total nutrient pool in the water and benthic algae. Waterfowl faeces appear to have low ratios of N to P, which will favour dominance of the phytoplankton by cyanobacteria in lakes where the faecal component of nutrient loads is large. The few data available suggest that the nitrogen content of waterfowl faeces is largely independent of that in their food. Food consumption, calculated by using cellulose as an indigestible faecal marker, was 104 g dry weight swan^–1 d^–1, a figure that appears low in relation to those for other swan species. Even the highest published figure for food intake by a swan is only about one half of the corresponding average metabolically-adjusted figures for geese, and we caution against the uncritical use of bioenergetic models for determining rates of food consumption and defaecation.     

Modification of the pathogenicity of Schistosoma mattheei for sheep by passage of the parasite in hamsters

Border Leicester X Suffolk sheep infected with a strain of S. mattheei maintained in hamsters do not develop the same pathological changes as Romney Marsh sheep infected with the same strain of parasite before hamster passage. To determine the cause of this reduced pathogenicity, five Romney Marsh sheep were each infected with 10 000 cercariae of the hamster-passaged parasite and five with 10 000 cercariae of a S. mattheei strain from Onderstepoort, South Africa, passaged exclusively through sheep. Striking pathological and parasitological differences were found between the two strains. Infection with the "sheep" strain was lethal, whereas infection with the "hamster" strain produced little evidence of clinical disease. By 13 weeks post-infection the mean body weight of the sheep infected with the sheep strain had declined by 15% compared with both the uninfected controls and the sheep infected with the hamster strain, and the mean PCV was lowered to 20% in the sheep strain infected animals. Egg production began at seven weeks with the sheep strain, faecal counts rising to more than 300 e.p.g., whereas only two of the sheep infected with the hamster strain passed eggs in the faeces (at nine weeks) and the maximum egg count was 50 e.p.g. Twice as many adult worms of the sheep strain were recovered, and, although the number of eggs found in the tissues "per worm pair" was not significantly different, overall egg production was higher for the sheep strain; also more of the sheep strain eggs were deposited in the intestines. Similar parasite differences were seen in a supplementary study in mice and it seemed that "attenuation" of the parasite had occurred, presumably due to its maintenance in hamsters. Histopathological observations and faecal egg counts both indicated an inability of hamster strain eggs to penetrate the intestinal lumen; this was probably important in reducing the pathogenicity of the hamster strain.     

Testosterone levels in Dorset and Romney rams and the effectiveness of these breeds in stimulating early onset of estrus in Romney ewes

Groups of Romney ewes were joined with either Dorset or Romney rams on December 24 1975 and further groups joined on January 30 1976. A control group was subjected to laparotomy and joined with Romney rams after first ovulation was observed. Matings were recorded daily in all groups. At weekly intervals rams were separated from ewes and bled every 10 minutes for one hour. The plasma was radioimmunoassayed for testosterone.Ewes run with rams showed their first estrus of the breeding season earlier than controls and their onset was more synchronised. The time of ram joining did not affect the time of first estrus but ewes joined with Dorsets showed their first estrus earlier than those with Romneys. Romney rams had significantly higher mean testosterone levels than Dorsets on 5 of the 11 weekly bleedings throughout summer. The testosterone level decreased significantly over the seven consecutive bleedings of the hourly sampling period in five weeks and a significant interaction between breed of ram and testosterone level of consecutive bleedings was observed in three weeks.The results show that testosterone levels in Dorset and Romney rams during summer do not reflect the effectiveness of the breeds in inducing the early onset of estrus in Romney ewes.     

A microsatellite analysis of five Colonial Spanish horse populations of the southeastern United States

The domestic horse (Equus caballus) was re-introduced to the Americas by Spanish explorers. Although horses from other parts of Europe were subsequently introduced, some New World populations maintain characteristics ascribed to their Spanish heritage. The southeastern United States has a history of Spanish invasion and settlement, and this influence on local feral horse populations includes two feral-recaptured breeds: the Florida Cracker and the Marsh Tacky, both of which are classified as Colonial Spanish horses. The feral Banker horses found on islands off the coast of North Carolina, which include, among others, the Shackleford Banks, the Corolla and the Ocracoke, are also Colonial Spanish horses. Herein we analyse 15 microsatellite loci from 532 feral and 2583 domestic horses in order to compare the genetic variation of these five Colonial Spanish Horse populations to 40 modern horse breeds. We find that the Corolla horse has very low heterozygosity and that both the Corolla and Ocracoke populations have a low mean number of alleles. We also find that the Florida Cracker population has a heterozygosity deficit. In addition, we find evidence of similarity of the Shackleford Banks, Marsh Tacky and Florida Cracker populations to New World Iberian horse breeds, while the origins of the other two populations are less clear.     

Production of Streptococcal M-Typing Antisera: I. Antigenic Response in Different Breeds of Rabbits

M-antigens of seven M-types of group A streptococci were used to compare antigenic response in six breeds of rabbits: New Zealand White, New Zealand Red, Dutch, Googy, California, and Palomino. No appreciable differences among breeds were demonstrated. M-types used for immunization varied considerably in their ability to evoke a response of an antibody which met rigid criteria for streptococcal M-typing antisera. The importance of the injection and bleeding schedule and absorption conditions for preparing type-specific absorbed antisera were demonstrated. Evaluating and processing sera from individual animals at an optimal time rather than using pooled sera enhanced the possibilities for preparing satisfactory type-specific antisera.     

The high sulphur proteins of wool: Towards an understanding of sheep breed diversity

High sulphur proteins (HSPs) form part of the matrix surrounding the intermediate filaments in the cortical cells of the wool fibre. There are three known families of HSPs, comprising in excess of 40 components and their molecular weights range from 10-30 kDa. Here we report the use of the increased resolving power of isoelectric focusing in the first dimension of two-dimensional electrophoresis and modern gel comparison software to investigate the nature of within- and between-breed variations amongst the proteins of three breeds of sheep: Merino, Romney and Corriedale. In agreement with past studies we observed very little variation in the intermediate filament protein content in wool, both between and within these three sheep breeds. Instead, most of the observed variation occurred among the HSPs, along with some minor variation among the high glycine-tyrosine proteins. Breed-specific differences were observed in the HSP patterns in the wool proteome maps. Merino sheep were found to exhibit the simplest HSP expression patterns, with eight major spots linked to form four pairs. In contrast, the Romney and Corriedale HSP patterns exhibited more spots at lower isoelectric point values (around 4.8), while some of the lower molecular weight HSPs were less prevalent in Romney sheep and absent from the Corriedales.     

Induced seasonal reproductive performance in two breeds of sheep

The objective of the present experiment was to determine whether failure to become pregnant through out-of-season reproductive management regimes is attributable to a failure to stimulate normal corpora lutea (CL) production. Romney ewes and East Friesian Composite (EF) ewes were mated in summer, autumn, winter, and early and late spring after administration of intravaginal progesterone inserts (plus eCG in spring and summer) in a factorial (two breedsxfive mating periods) experimental design. Oestrus rate was determined from mating data, and the numbers of CL were determined by laparoscopy 9 days after ram introduction. Conception rate, pregnancy rate and litter size were determined by transabdominal ultrasonography 62 days after ram introduction. Proportions of ewes displaying oestrus did not differ significantly (75-100%) between seasons or breeds, except for the Romney ewes in summer (67%; P<0.05). Numbers of CL on Day 9 for EF ewes was lowest in autumn (1.5) and winter (1.5), and highest in late spring (2.1; P<0.05). In contrast, Romney ewes had the lowest CL count in summer (1.3), and the highest in autumn (1.8) and winter (1.6; P<0.05). Only in summer was there a difference between breeds (EF 1.8; Romney 1.3; P<0.01). The proportion of ewes that failed to conceive despite having one or more CL present was highest in late spring (EF 41%, Romney 43%), and lowest in autumn (EF 9%, Romney 4%) and winter (EF 14%, Romney 4%; P<0.05). Conception and pregnancy rates followed similar patterns with values for autumn (EF 91%, 91%; Romney 96%, 96%) and June (EF 86%, 82%; Romney 91%, 83%) being significantly (P<0.05) higher than in early (EF 50%, 40%; Romney 54%, 50%) and late spring (EF 44%, 36%; Romney 42%, 36%). Pregnancy rate in summer was higher for EF ewes (60%) than for Romney ewes (39%) but conception rates were not statistically different (EF 68%; Romney 60%). Numbers of foetuses identified at scanning was highest in autumn (1.5) and lowest in late spring (0.5 P<0.001): Litter size in pregnant EF ewes was highest in early spring and lowest in winter (1.8 versus 1.2; P<0.01), but for pregnant Romney ewes was highest in winter and lowest in early spring (1.9 versus 1.3; P<0.001). It was concluded that seasonal differences in the ability of ewes to conceive are not the consequence of failure to display oestrus or to ovulate, but probably are a result of failure of fertilisation or the establishment of pregnancy.     

An assessment of sperm motility estimation for evaluation in rams

There is disagreement about the value of estimating spermatozoal motility as a predictor of fertility in rams. We tested the hypothesis that sperm motility can help one to predict lambing rate by evaluating sperm motility in rams prior to breeding and by subsequently breeding the rams regardless of their sperm motility results. A total of 943 rams (Merino, n=630 and Romney Marsh, n=313) was used during two breeding seasons. For fertility evaluation only 804 rams that bred at least ten ewes each were included in the study. Rams were grouped into 4 groups according to sperm motility scores, ranging from the lowest, which included rams with azoospermia, oligospermia, non-motile and single-motile sperm, through rams with 10 to 30%, 30 to 60%, to the highest at 60 to 100% motile sperm. The corresponding fertility rates found in our study in Merino and Romney breeds were 58.3 and 47.4%, 75.1 and 59.1%, 79.4 and 64.1% and 81.5 and 64.0%, respectively. We concluded that there was a statistically confirmed difference in fertility between the lowest and all the other motility categories. The differences in fertility among rams that had motility categories above 10% were not statistically significant. Evaluation of breeding soundness in large scale surveys of rams, based on sperm motility estimation, may be misleading. Clinical examination of genital organs seems to offer a reliable source of information about rams, and may be considered adequate in sheep breeding.     

Plasma melatonin profiles of Romney Marsh sheep in natural photoperiod and in acutely extended darkness.

Plasma melatonin was measured at the summer and winter solstices and the autumn and spring equinoxes in Romney Marsh sheep held under natural conditions in South Australia (35 degrees S). The amount of melatonin detected was generally related to the extent of natural darkness, though the melatonin onset was particularly delayed after dusk in winter compared with other seasons. The duration of detectable melatonin was shorter in summer than at any other season. After each initial 24 h sampling, the sheep were resampled for a further 24 h in acutely extended darkness to mark the phase and duration of suprachiasmatic nuclei activity which is believed to be the source of the melatonin signal. The onset of high plasma melatonin was earlier than the time of natural sunset in spring and summer, but not different from the time of natural sunset in autumn and winter. The offset of high plasma melatonin was later than the time of natural sunrise at all times of year and particularly so in summer. Under the extended dark conditions, the duration of detectable melatonin was longer than that under natural photoperiod at all seasons of the year and the duration of melatonin was again shorter in summer than winter. If melatonin measurements under the conditions of extended darkness do reflect the phase and duration of suprachiasmatic nuclei function then the natural light of the photoperiod can, particularly during long photoperiod conditions, mask the expression of the pacemaker. The findings may have implications for the timing of the breeding season in Romney Marsh sheep.     

Response of

The fish prey consumed by New Zealand fur seals (Arctocephalus forsteri) was investigated by analysis of faeces collected between February and August at sites on the east and west coasts of South Island, New Zealand. Twelve species were identified from otoliths recovered from faeces. Lanternfish (Symbolophorus sp. and Lampanyctodes hectoris), the most frequent fish prey, comprised 79% of all otoliths, followed by anchovy (Engraulis australis) at 12%, ahuru (Auchenoceros punctatus) with 3.9%, and hoki (Macruronus novaezelandiae) at 3.7%. Of these species only hoki is commercially important. Regional and seasonal differences in the proportions of species were evident, and the results are compared with those from previous studies.     

Moss biogeography in the Tasman Sea region

Abstract

Panbiogeographic track analysis is applied to the distribution of several groups of mosses which occur in the New Zealand region. The analysis highlights areas of biogeographic interest (nodes) in the New Zealand region as follows: 1. New Guinea, 2. New Caledonia, 3. New South Wales/Queensland border in Australia, 4. northern New Zealand, 5. Rapa Island, 6. subantarctic New Zealand.

New Zealand is connected to these nodes by the following standard tracks: 1. New Guinea—New South Wales/Queensland border—Tasmania—subantarctic New Zealand, 2. New Guinea—New Caledonia—New Zealand—subantarctic New Zealand, 3. a central Tasman Sea transversal track; New South Wales/Queensland border—New Caledonia. Rapa Island is connected to the Tasman region by northern New Zealand and New Caledonia.     

Statistical comparison of Campylobacter jejuni subtypes from human cases and environmental sources

AIM: To analyse Campylobacter jejuni typing data to define statistically which potential reservoirs and transmission sources contain isolates that are most similar to one another and to isolates from human infections. METHODS AND RESULTS: Serotyping and SmaI macrorestriction profiling data for C. jejuni isolates from human campylobacteriosis cases, chicken carcass rinses, duck, sheep, dairy and beef cattle faeces, river water, and sheep, beef and pork offal obtained from a defined rural area of New Zealand were compared using the Czekanowski proportional similarity index. Subtypes of isolates from ruminant animals, whether derived from their faeces or offals, were generally similar to one another. The spectrum of isolate subtypes from human cases was more similar to that from ruminant faeces than the other matrices considered. Isolate subtypes from chicken rinses, pork offal, water and duck faeces were not highly similar to those from other matrices. CONCLUSIONS: Results from a combination of phenotypic and genotypic approaches suggest that, for this rural population, exposures associated with a rural lifestyle may be significant sources of human campylobacteriosis. SIGNIFICANCE AND IMPACT OF THE STUDY: The Czekanowski index was applied to subtyping data and supported the greater importance of contact with livestock in campylobacteriosis cases associated with a rural setting, in comparison with urban studies that have identified poultry-related factors.     

A Morphometric Method to Assist in Defining the South American Origins of Microctonus hyperodae Loan (Hymenoptera: Braconidae) Established in New Zealand

In 1991, Microctonus hyperodae Loan (Hymenoptera: Braconidae, Euphorinae), collected from eight diverse South American locations, was released in New Zealand as a biological control agent of the pasture pest Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae). Equal numbers of each South American geographical population of this thelytokous endoparasitoid of adult hosts were released in New Zealand. A morphometric method described in this paper provided a means of classifying M. hyperodae adults as originating from either east or west of the Andes. Analysis revealed that, on average, specimens collected in Chile had significantly more antennal segments, narrower stigmas and longer radial cells than those collected in Brazil, Uruguay and Argentina. Significant differences between populations originating from each side of the Andes were also recorded in the dimensions of metasomal tergum one and basitarsus three. The morphometric method should, therefore, assist in defining the origins of M. hyperodae established in New Zealand. This information will be used in attempts to ascertain the importance of climate matching and host-parasitoid co-evolution to the outcome of the L. bonariensis biological control programme.     

Polymorphisms in the ovine myostatin gene (MSTN) and their association with growth and carcass traits in New Zealand Romney sheep

Myostatin is a regulator of myogenesis and has been implicated in the regulation of adiposity and in controlling the structure and function of tendons. Polymerase Chain Reaction Single-Stranded Conformational Polymorphism (PCR-SSCP) analysis of intron-1 was used to identify five variants (designated A-E) of the myostatin gene ( MSTN ). The effect of this genetic variation on growth and carcass traits was investigated in 517 Romney male lambs from 17 sire-lines, born on a South Island New Zealand farm. General linear mixed effect models revealed that the presence of allele A in a lamb's genotype was associated with decreased leg, loin and total yield of lean meat, whereas the presence of allele B was associated with increased loin yield and proportion loin yield (loin yield divided by total yield expressed as percentage). The effect of the number of allele copies present was investigated, and it was found that the absence of A , or the presence of two copies of B , was associated with increased mean leg yield, loin yield and total yield. Two copies of B were also associated with a decrease in proportion of shoulder yield, whereas two copies of A were associated with a decrease in proportion of loin yield. Associations with allele C were not detected. No associations of MSTN variation with birth weight, weaning weight, pre-weaning growth rate, draft age and hot carcass weight (H-W) were detected. These results suggest that variation in ovine MSTN is associated with meat production, but not birth weight or growth rate in New Zealand Romney sheep.     

125I-labelled hCG binding characteristics in theca interna and other tissues from Romney ewes and from Booroola x Romney ewes with and without a major gene influencing their ovulation rate

Specific receptors for 125I-labelled hCG in ovarian follicle wall were located in the theca interna. No specific binding of 125I-labelled hCG was found in theca externa and/or stromal tissue. The kinetics of 125I-labelled hCG binding to theca interna followed second order kinetics with calculated association rate constants (ka +/- s.d.) of 1.57 +/- 0.16 X 10(6) and 0.57 +/- 0.02 X 10(6) litres mol-1 sec-1 at 37 degrees C and 22 degrees C respectively. Dissociation of specifically bound 125I-labelled hCG from theca interna was minimal at 37 degrees C and 22 degrees C. The binding of 125I-labelled hCG to theca interna could be displaced with PMSG, FSH-P and sheep LH but other sheep pituitary hormones and LH-releasing hormone showed little or no cross-reaction. The calculated binding capacities (Bmax) and equilibrium dissociation constants (Kd) for 125I-labelled hCG binding to theca interna did not differ between Romney ewes and Booroola x Romney ewes with and without the fecundity (F) gene on Day 10 of the oestrous cycle, during anoestrus or at 36 h after an injection of cloprostenol on Day 10 of the oestrous cycle. When the data for Day 10 and anoestrus were pooled, the median (range) Bmax and Kd values in non-atretic follicles (greater than or equal to 3 mm diameter) were 12.0 (5.1-23.5) fmol/mg protein and 0.10 (0.05-0.16) nM respectively. At 36 h after cloprostenol injection the respective median (range) Bmax and Kd values in non-atretic follicles (greater than or equal to 3 mm diam.) increased to 46.9 (28.4-70.3) fmol/mg protein and 0.23 (0.13-0.65) nM respectively. In corpora lutea the hCG binding characteristics were similar in all the above breeds/genotypes. On Day 10 of the cycle, the mean Bmax but not the mean Kd value was significantly higher (P less than 0.01) than the corresponding value at 36 h after cloprostenol injection. In granulosa cells, from follicles of greater than or equal to 5 mm diameter of Romney and Booroola x Romney (++) ewes and from follicles of greater than or equal to 3 mm diameter of Booroola x Romney (F+) ewes, the hCG binding characteristics were similar. In granulosa cells from smaller sized follicles from the above breeds/genotypes, no specific hCG binding was noted.     

Genetic polymorphism in sheep plasma detected using antibodies to human plasminogen

Protein variation was identified in sheep when Western blots of polyacrylamide gels (routinely used to resolve transferrin polymorphism) were stained using antibodies to human plasminogen. The affinity of the antibodies to ovine plasma was less than 7% that of a human standard but they bound specifically to a single polymorphic protein. In 146 lambs and their parents the inheritance of the ovine plasminogen antigen polymorphism was consistent with four autosomal alleles segregating codominantly. However, an additional two lambs had types which were incompatible with their putative parents. The pedigrees of these lambs were tested by DNA fingerprinting and shown to have been incorrectly recorded. The genetic polymorphism detected by human plasminogen antiserum provided a probability of sire exclusion (PE) ranging from 0.04 to 0.32 and a polymorphic information content (PIC) of 0.08 to 0.50 in flocks of five sheep breeds: Perendale, Romney, Merino, Texel and Coopworth (in order of increasing genetic variation in this locus). Significant differences in allele frequency were observed between breeds but sampling did not assess the variation among flocks within a breed.