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PubMed1986

Reproductive biology of the male Cape porcupine, Hystrix africaeaustralis.

The reproductive tract of the male Cape porcupine is morphologically and histologically similar to that of New World hystricomorph rodents. Males are reproductively active throughout the year and attained sexual maturity (complete spermatogenesis) at an age of 8-18 months. Testes weight, epididymides weight and seminiferous tubule diameter attained asymptotic values at the age of 23-30 months. A tendency towards seasonality in the activity of accessory glands, preceded and accompanied by an increase in circulating plasma testosterone values, may be considered as a factor enforcing seasonal breeding in females. Testosterone concentrations in pubertal males were significantly higher than those recorded in sexually mature males.

Animals↗
PubMed2002

A study of associations of the H-FABP genotypes with fat and meat production of pigs.

Although the content of intramuscular fat (IMF) influences significantly meat quality, it can be estimated only after the slaughter of animals. Variants of the H-FABP gene were suggested as candidate genes influencing the variability of IMF. The effect of H-FABP - HinfI polymorphism on the content of IMF, backfat thickness, the weight and percentages of major meat parts and of the leg in carcass weight was studied in a group of 97 pigs (46 gilts and 51 barrows) of Large White and Landrace breeds using the test of fattening capacity and carcass value. In the set of experimental animals, the frequencies of genes were H = 0.75 +/- 0.03 and h = 0.25 +/- 0.03. Biometric analyses did not corroborate differences among different H-FABP - HinfI genotypes and all the traits under study. Only in genotypes HH and Hh the differences between least-square means of phenotypic IMF values under study were close to the limit of significance (P = 0.06).

Animals↗
PubMed1986

[Variability of muscular tissue distribution in the hindlimb of lambs. I. Individual muscles].

Using multivariate analysis of the centered data, this paper describes the extent of variation of the weight distribution of individual muscles in the hindlimb of lambs of 18.9 +/- 3.1 kg carcass weight. We studied a sample of 52 ram lambs and 36 ewe lambs of different morphological types slaughtered at a comparable stage of body development (same relative state of carcass fattening). Variability in muscle weight was similar in the two sexes (average CV = 21.95% in ram lambs and 22.5% in ewe lambs) and changed from 14.84 to 43.91% in the former and from 14.91 to 41.93% in the latter. Some of the mass variability of the different muscles was related to the total muscle weight of the hindlimb, but a part was also due to intrinsic variation related to the nature of the muscles. The most discriminant variables of the population were of very low weight: Soleus (SO), Extensor digitorum lateralis (ED), Gemelli (GE) and Quadratus femoris (QF); moderately low weight: Sartorius (SA); or average weight: Vastus medialis (VM). Their order of importance was not the same in the two sexes. The breed groups could be distinguished by the weight ratio values of these muscles.

Animals↗
PubMed1982

Androgens, behaviour and fertility control in feral stallions.

This field study of feral stallions in Montana and Idaho examines and correlates the seasonal pattern of plasma androgens and specific sociosexual behaviour and reports the effect of a long-acting androgenic steroid on this behaviour and on fertility. Plasma testosterone was measured by competitive protein binding assay in samples obtained by jugular venepuncture from captured animals. In samples taken from 34 sexually mature stallions in 6 different months during the year, a definite seasonal pattern in testosterone was present, with a peak in May (3.04 +/- 0.63 ng/ml) and a nadir in December (1.55 +/- 0.34 ng/ml). Values were less than 2.0 ng/ml in non-breeding months and greater than 2.4 ng/ml in breeding months. Behavioural endpoints measured were (1) stallion scent marking in response to elimination by mares (elimination marking), (2) mounting and (3) copulation. The frequencies of each of these endpoints followed closely the seasonal pattern seen for plasma androgens. In the fertility study microcapsulated testosterone propionate (microTP) was administered i.m. to 10 harem stud stallions 3 months before the 1980 breeding season. In these stallions and in 10 control harem studs, the above behavioural endpoints were examined in the 1980 and 1981 breeding seasons, and foal counts were made in 1981. There were no direct inhibitory or stimulatory effects of microTP treatment on any of the behavioural endpoints in either year. In 1981 foals were produced in 87.5% of the control bands and 28.4% of the microTP-treated bands. These results indicate that microencapsulated testosterone propionate can provide effective fertility control in feral horses without causing significant alterations in sociosexual behaviour.

Animals↗
PubMed1997

[Hemoglobin derivatives in blood of cattle during during winter housing. Effect of age as well as developmental and functional conditions].

Peripheral venous blood samples taken from pregnant and lactating dairy cattle, from young cattle and from new born calves as well were analysed for hemoglobin content, hematocrit, oxygen saturation, oxygen capacity, oxygen content and for the hemoglobin derivatives O2Hb, HHb, COHb, MetHb and SHb. Significant differences of mean values could be pointed out between age groups and breeds. Strong negative correlations exist between MetHb fraction and hemoglobin content in dairy cattle and in new born calves but not in young cattle. Elevated COHb and MetHb fractions were discussed in connection with erythropoesis, regeneration of erythrocyte mass and vascular adaptation.

Aging↗
PubMed2004

Heterogeneity in stable isotope profiles predicts coexistence of populations of barn swallows Hirundo rustica differing in morphology and reproductive performance.

Population studies assume that individuals belonging to a study population are homogeneous for natal and breeding origin, although this assumption is rarely tested. We tested for heterogeneity in stable-isotope profiles (delta15N, delta13C, deltaD) of feathers grown in the African winter quarters from a Danish breeding population of adult barn swallows, Hirundo rustica. Deuterium isotope values did not provide useful information on population segregation of wintering swallows in Africa. However, both delta15N and delta13C values showed a clearly bimodal distribution with 6% belonging to one category and the remaining birds belonging to another category, resulting in this population comprising three categories of birds. Adults belonging to the two categories of delta13C isotope profiles differed weakly in morphology for several different characters. The frequency and the size of second broods differed between categories of delta13C isotope profiles. Phenotypes of nestlings from the first brood in terms of tarsus length, body mass and T-cell response differed significantly between the two delta15N isotope categories, suggesting that conditions during winter carried over to the breeding season at least as late as the first brood. Polymorphism can be maintained only if fitness is similar for birds from categories of isotope profiles. We suggest that fluctuating selection or migration-selection balance may maintain the observed polymorphism.

Analysis of Variance↗
PubMed1982

A breeding study to control chronic progressive nephrosis in rats.

Breeder male Sprague-Dawley rats were categorized as potential low and high protein excretors at 4 months of age. The average selection values of these two groups were 0.59 and 1.75 mg/ml, respectively. Paris of females were mated to these males in two breeding cycles in the fashion of a diallele cross. The heritability index based on protein excretion values of 263 male offspring at 6 months of age from both cycles of high and low excretor males was 0.526 with approximate variance of 0.0668. Significantly different (p less than 0.01) survival distributions were shown. The mean and median survival times of the high excretor offspring were 611.1 and 652 days, respectively, compared to 651.4 and 680.5 days, respectively, in low excretor offspring. The proportion of offspring with marked chronic progressive nephrosis was significantly greater (p less than 0.01) in the high excretor group, both prior to and after 700 days of age, than that of offspring in the low excretor group. The selection of low excretor males for breeding stock appears to offer a practical basis for minimizing the total expression of chronic progressive nephrosis in this strain of rat.

Animals↗
PubMed1991

Production of two species of interferon by Large White and Meishan pig conceptuses during the peri-attachment period.

Antiviral activities present in uterine flushings from pregnant Large White, Large White 'hyperprolific', and prolific Meishan gilts, between Days 8 and 20 of gestation were compared. Flushings (20 ml) from all gilts between Days 14 and 20 were positive in an in-vitro interferon (IFN) assay using vesicular stomatitis virus as a challenge infection. Highest antiviral activities (of up to 400,000-1,200,000 total Units/flushing) were obtained at Day 16 of gestation, i.e. clearly after the beginning of attachment. There was no major difference between breeds although, at Day 14, flushings from Meishan gilts yielded significantly higher titres than those from the other two, suggesting a correlation with the previously described earlier trophoblast elongation in Meishan gilts. Conceptus cultures contained antiviral activity, with values very close to those obtained in vivo, but the difference between breeds was not significant. Cultures from Day 20 on contained very little antiviral activity. The antiviral activity was associated with a mixture of at least two IFNs, one of which was IFN-alpha like, and the other was serologically identified as an IFN-gamma, that is an 'immune IFN', previously found to be secreted only by T lymphocytes. This finding may have implications for our understanding of the immunology of early pregnancy.

Animals↗
PubMed2001

Photoperiodic control of the concentration of luteinizing hormone, prolactin and testosterone in the male emu (Dromaius novaehollandiae), a bird that breeds on short days.

The objective of this study was to establish, for a short-day breeding bird, the male emu, whether the breeding season is principally controlled by changes in photoperiod, and to investigate the endocrine mechanisms involved. Two groups of adult males were subjected to three alternating periods of 150-185 days of 14 h light/day (LD) and 10 h light/day (SD) terminating in a 360-day period of LD or SD. Transfer from LD to SD led to increases in plasma concentrations of luteinizing hormone (LH) and testosterone, after 82 +/- 8 and 73 +/- 3 (SEM) days, and an increase in prolactin concentrations after 115 +/- 12 days. Concentrations of LH and testosterone began to decrease before transfer back to LD, at a time when prolactin concentrations were approaching peak values. Transfer from LD to 360 days of SD resulted in increases in LH and testosterone concentrations, and these terminated after an increase in prolactin concentrations. After transfer from SD to 360 days of LD, plasma concentrations of LH and testosterone began to increase, after delays of 222 +/- 24 and 225 +/- 13 days, and were high at the end of the study, while prolactin values remained depressed throughout. These observations clearly show that seasonal breeding in the emu is directly controlled by changes in photoperiod. The dynamics of the hormonal responses to change of photoperiod suggest that, despite being short-day breeders, the photoregulation of breeding in emus involves mechanisms that are currently accepted for birds, rather than mechanisms that have been proposed for short-day breeding mammals. The initiation of breeding in emus is due to dissipation of photorefractoriness by short days which leads to an increase in the secretion of gonadotrophins to levels that are sufficient to support full reproductive condition. The termination of breeding, while days are still short, is due to the antigonadotrophic action of prolactin which, unusually for birds, increases while the days are still short. In conclusion, breeding activity in male emus is strongly controlled by photoperiod. Emus are short-day breeders, but the central mechanisms that regulate the secretion of reproductive hormones seem to be similar to those previously proposed for long-day breeding birds. The pattern of prolactin secretion in emus suggests an important role for this hormone in the termination of the breeding cycle.

Animals↗
PubMed2006

Genetic variations of 13 indigenous Chinese goat breeds based on cytochrome B gene sequences.

Phylogenetic relationships among and genetic variability within 13 Chinese indigenous goat breeds and Boer goat were analyzed using cytochrome b gene sequences. There were 44 variable sites found in a 642 bp sequence, and 46 Cyt b haplotypes were subsequently defined. The phylogeny analysis of haplotypes in combination with goat Cyt b sequences from GenBank shows that Chinese goats are obviously separated from wild goats and might come from Capra aegagrus. Further analysis indicated that indigenous Chinese goats might descend from at least two lineages; most of the individuals analyzed could be classified into lineage A as defined by Luikart, but five other goats were of uncertain lineage. The Tibet plateau is a possible place of origin for Chinese goats. The neighbor-joining tree based on pairwise differences among populations shows that most Tibetan goats, except the Middle Tibet type, cluster closely with North China goats, and then with South China goats. This result confirms that differences in genetic structure exist among goats in different geographic locations. Nucleotide diversity varied among populations. Tibet and North China goats had higher genetic diversity than South China goats. The fixation index (F (st)=87.72%) suggested that most of the total genetic variation was due to variation within populations. In addition, the results indicate that Cyt b gene sequence information alone might not be enough for phylogeny analysis among breeds within species, as shown by fewer polymorphic sites and lower bootstrap values on the neighbor-joining tree.

Animals↗
PubMed2025

Exploration of the genetic diversity of Avena Fatua L. (wild oat) through genotyping-by-sequencing and SDS-PAGE.

BACKGROUND: The consumption of oats has rapidly increased due to their exceptional nutritional value. However, concerns over genetic erosion have emerged as oat breeding programs rely on a highly limited genetic pool. This study aimed to expand the genetic diversity pool of oats by collecting wild oat (Avena fatua L.) populations in South Korea and assessing their genetic diversity and seed storage protein patterns. RESULTS: A total of 237 A. fatua individuals were collected in 2022 from eight regions in the southwestern coastal areas of South Korea. Genetic diversity and seed storage protein patterns were analyzed using genotyping-by-sequencing (GBS) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The GBS analysis identified 20,836 single-nucleotide polymorphisms (SNPs). An analysis of molecular variance (AMOVA) based on regional populations revealed that 40.9% of the genetic variation was attributed to differences among populations, while 59.1% was within populations, indicating high genetic differentiation within regional populations. Subsequent population structure analysis and discriminant analysis of principal components (DAPC) both stated the formation of two distinct genetic groups, with an AMOVA value of 70.9% between the groups, suggesting a high level of genetic variation. Pairwise FST analysis was conducted to compare the genetic differentiation between two populations, revealing that Jindo and Jangheung exhibited the highest level of genetic differentiation (FST = 0.795) among the geographic groups. Seed storage proteins were analyzed using SDS-PAGE, and the patterns were grouped using k-means clustering. A comparison between the groups based on protein patterns and those based on genetic variation revealed no significant correlation. CONCLUSION: This study provides data on the genetic diversity of A. fatua, a wild relative of cultivated oats, aimed at expanding the genetic pool of oats for future breeding programs. These findings are expected to be a foundational resource for oat breeding and genetic improvement efforts.

Genetic Variation↗
PubMed2005

Genotypic variability for carbon isotope discrimination in the mutant and improved lines of barley.

Drought tolerance is an important breeding objective in dry and semi-dry conditions. Carbon isotope discrimination (Delta) is a tool that may be used to improve water-use efficiency (WUE) as an indirect selection criterion. The study investigated the variability for Delta in improved F7 lines and their parents (three cultivars and two mutant lines), which were sampled randomly from an F6 nursery performing well under semi-dry conditions. In total, 40 entries were grown in sand culture, arranged in three-replicated randomized complete block designs in two sets of experiments in Antalya, Turkey. There were statistically significant differences (p<0.01) among genotypes in both sets of experiments for Delta, and Delta values range from 20.14 to 21.86. Low coefficient of variation (C.V.) values, i.e. 2 and 1.65 %, for both data sets revealed efficient control of experimental error for Delta and indicated little effect of environment. Consequently, broad-sense heritability estimates for Delta were 0.63 and 0.74. As Delta showed a considerably high heritability and consistency over the two sets of experiments and low C.V. values, it was concluded that this trait could be used in breeding programmes aimed at developing drought tolerance lines. The early heading mutant, M-K-88, and the cultivar selected from land race, Tokak 157-37, showed lowest Delta values, indicating that they had the best water-use efficiency. Low Delta values of these two genotypes were inheritable.

Carbon Isotopes↗
PubMed1984

Marginal copper deficiency in rats. Aortal morphology of elastin and cholesterol values in first-generation adult males.

A marginal, 2 parts per million (ppm) copper diet (experimental) was fed to female rats for 4 months prior to breeding, through gestation/lactation, and to the weaned offspring to determine the consequences in adult, male offspring on cholesterol values and aortal morphology. Liver copper concentrations of the dams and pups at day 21 of lactation and of the 117-day-old offspring who consumed the experimental diet were lower (P less than 0.0001) than corresponding rats fed a 10 ppm copper diet (control). However, statistically significant differences due to dietary treatments were not evident in pre- or post-weaning gain in body weight, litter size, cannibalism of pups, or total cholesterol concentrations of the serum and aorta. Ultrastructural examination of experimental offspring aortas revealed focally abnormal features of endothelial cells, the subendothelial space, collagen fibers, smooth muscle cells, and particularly elastin. The ultrastructural irregularities of elastin included discontinuous regions of the internal elastic lamina comprised of stained clumps of elastin of irregular size and shape. The results of this study suggest that a marginal copper nutriture begun in utero will elicit morphologic abnormalities of the aorta in rats that are otherwise without overt signs of copper deficiency.

Animals↗
PubMed1988

Oxygen transport properties of blood in two different bovine breeds.

1. The whole oxygen dissociation curve of oxyhemoglobin has been determined in double-muscled cattle of the Belgian White Blue breed and in Friesian cattle of different body weight. 2. In calves, P50 values are low and DPG level is high (4-20 mumol/g Hb). 3. P50 values of 25 +/- 1.4 mm Hg (mean +/- SD) and a level of DPG less than 1.5 mumol/g Hb have been found in animals weighing more than 80 kg. 4. Effects of temperature and pH on the oxygen dissociation curve have been measured at all levels of saturation. The temperature coefficient (dlog P50/dT) and the Bohr effect expressed as dlog P50/dpH were 0.017 and -0.40, respectively. 5. Hematocrit, hemoglobin concentrations and oxygen capacity of hemoglobin have been measured. 6. No difference between both breeds has been observed. 7. These data can be used to correct measured values of oxygen tension for temperature and pH and to measure oxygen content of blood in cattle.

Animals↗
PubMed2000

Reproductive characteristics of Ethiopian highland sheep. II. Genetic parameters of semen characteristics and their relationships with testicular measurements in ram lambs.

A study was conducted to investigate the effect of season on, and to estimate heritabilities of, and genetic correlations among, semen and spermatozoa characteristics and the relationship of these characteristics with measures of testicular or scrotal size in 6-, 9- and 12-month old ram lambs of Menz and Horro sheep breeds indigenous to Ethiopian highlands. A total of 278 ram lambs with substantial pedigree information were involved in the study. There was improvement in all semen and spermatozoa traits with age, the means at 12 months being consistently superior to values at 6 and 9 months of age. There were no significant breed differences in any of the traits studied, except semen volume at 9 months (0.67, S.E. 0.07 for Horro versus 0.39, S.E. 0.05ml for Menz) and proportion of dead spermatozoa at 12 months (0.18, S.E. 0.03 versus 0.23, S.E. 0.02, respectively). Season was significant (p<0.05) for most of the traits studied, and differences were attributed primarily to nutrition. Semen collected in the wet season had higher spermatozoa concentration while samples collected in the dry season had higher proportion of abnormalities. After correcting for differences in total spermatozoa abnormalities, the wet season (of collection) had the highest spermatozoa output (volumexconcentration) in 12-month old ram lambs. Heritability estimates varied substantially in magnitude, ranging from zero to over 0.4. Traits with non-trivial heritability estimates were mass motility at 9 months (0.32, S.E. 0.11), individual motility at 9 months (0.32, S.E. 0.12) and at 12 months (0.16, S.E. 0.12) and proportion of abnormal spermatozoa at 9 months (0.35, S.E. 0.13). Genetic correlations among semen and spermatozoa characteristics, as well as correlations with testicular measurements, were medium to high and generally favourable, but were associated with large standard errors. The genetic correlations of scrotal circumference with semen volume (0.55, S.E. 0.11), mass motility (0.62, S.E. 0.20), individual motility (0.54, S.E. 0.12), concentration (0.25, S.E. 0.04) and proportion of abnormal spermatozoa (-0.75, S.E. 0.24) in 12-month old rams indicated that selection based on this trait, which is highly heritable and easy to measure and can be measured early in life, should have appreciable favourable correlated response in semen quality and spermatozoa production.

Journal Article↗
PubMed1994

Breed differences and genetic parameters for body composition traits in beef cattle.

The recent scientific literature was reviewed to summarize breed differences and genetic parameters for carcass traits in beef cattle. Heritability estimates were generally moderate to large, suggesting good potential for accurate genetic selection for a given individual carcass characteristic. However, effectiveness of multiple-trait selection for some trait combinations could be slowed by genetic antagonisms between traits, suggesting the use of terminal breeding systems with complementary sire and dam genetic types. Individual and maternal heterosis estimates from age-constant analyses were numerically positive for most carcass traits, although estimates from weight-constant analyses were generally nonsignificant. Potential contributions to improved carcass composition from crossbreeding would primarily result from genetic complementarity rather than heterosis. Considerable variation exists between breeds for body composition, and breed rankings vary across different traits. Studies have consistently indicated reduced meat tenderness for Bos indicus compared with Bos taurus breeds. Some differences in breed rankings for marbling vs tenderness were noted. If the U.S. beef industry shifts toward a more value-based marketing system, some genetic concerns will include 1) an apparent antagonistic relationship between marbling and cutability across breeds and within some breeds, 2) inconsistency of beef tenderness, particularly in Bos indicus cattle, 3) the effect of increased leanness on female reproductive performance, and 4) the extent to which terminal breeding systems can be used.

Animals↗
PubMed2005

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: V. Reproduction of F1 ewes in spring mating seasons.

Objectives were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), dam breed [Composite III (CIII) and northwestern whiteface (WF)], mating season (March and May), and their interactions on reproductive traits of mature F1 ewes in spring mating seasons. A total of 1,099 F1 ewes produced 1,754 litters of 2,995 lambs from exposures to Suffolk rams during March and May mating seasons in 1995 through 1999. Fertility rate and ewe longevity were measured. Number born and litter birth weight were recorded, and number and weight at weaning and 20 wk of age were analyzed separately for dam- and nursery-reared litter mates. Total productivity from 4 to 6 yr of age for each ewe entering the breeding flock was calculated as the sum of 20-wk weights for dam-reared lambs and separately for nursery-reared lambs. Interactions of sire breed x mating season, ewe age x mating season, and ewe age x dam breed were often significant. Interactive effects of sire breed and mating season on fertility rate (P < 0.001) were primarily due to differences in magnitude. Fertility rates of sire breeds for March and May matings, respectively, were 92 and 89% for Romanov, 91 and 72% for Finnsheep, 90 and 52% for Texel, 88 and 52% for Montadale, and 83 and 62% for Dorset. Sire breed x mating season also affected number born (P < 0.03); March and May values were 2.12 and 2.05 for Romanov, 2.00 and 1.94 for Finnsheep, 1.39 and 1.41 for Texel, 1.37 and 1.51 for Montadale, and 1.37 and 1.55 for Dorset, respectively. Interaction of sire breed x dam breed on fertility rate (P < 0.01) was due to change in rank as well as magnitude. Romanov- and Dorset-sired ewes out of CIII dams had greater fertility rates than Romanov- and Dorset-sired ewes out of WF dams. The opposite situation existed for ewes by Finnsheep, Texel, and Montadale sires. Differences between dam breeds (CIII and WF) in total productivity of dam-reared lambs were not detected, whereas ewes exposed in March (78 kg) were more productive (P < 0.01) than those exposed in May (68 kg). Means of sire breeds for total productivity of dam-reared lambs were 47, 65, 70, 70, and 111 kg for Texel, Montadale, Dorset, Finnsheep, and Romanov, respectively (P < 0.001). Superior reproduction of Romanov sired ewes was primarily due to greater fertility rate and prolificacy at each mating season and ewe age. Use of Romanov-crossbred ewes would increase fertility during spring mating, an important constraint of the sheep industry.

Aging↗