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PubMed2006

Changes in serum inhibin levels and immunolocalization of inhibin/activin subunits during the breeding season in the wild male Japanese black bear (Ursus thibetanus japonicus).

The objective of this study was to investigate the changes in secretion of inhibin and cellular localization of inhibin alpha and inhibin/activin (beta(A) and beta(B)) subunits during the breeding season in the wild male Japanese black bear. Histological observations of testes were performed and seminiferous tubule diameters were measured. The sections of the testes were immunostained by the avidin- biotin-peroxidase complex method (ABC) using polyclonal antisera raised against porcine inhibin alpha, inhibin/ activin beta(A), and inhibin/activin beta(B) during the breeding season. Serum concentrations of immunoreactive (ir-)inhibin, testosterone, and luteinizing hormone (LH) were measured by radioimmunoassay. Higher values of seminiferous tubule diameters and all types of spermatogenic cells including mature-phase spermatozoa were found during the breeding season. There were seasonal changes in serum concentrations of ir-inhibin, testosterone, and LH. Ir-inhibin was positively correlated with testosterone, and LH. In addition, immunoreactivity of inhibin alpha, beta(A), and beta(B) subunits were also detected in Sertoli and Leydig cells during the breeding season. These results suggest that Japanese black bear testes may secrete bioactive inhibins during the breeding season and that the circulating inhibin may be a useful indicator of the testicular function in wild male Japanese black bears.

Activins↗
PubMed1986

Variations in patterns of follicle development in prolific breeds of sheep.

Prolific breeds of sheep (Romanov, Finn and Booroola Romanov crosses heterozygous for the Booroola gene (F+) were compared with breeds of lower prolificacy (Ile-de-France, Finn X Scottish Blackface, Merino X Blackface and Booroola X Romanov not carrying a copy of Booroola gene (++] by in-vivo monitoring of follicular kinetics by ink labelling during the late luteal phase and follicular phase of the oestrous cycle followed by histological examination of the ovaries or follicle dissection. At each of 3 successive laparotomies, the 3 largest follicles of each ovary were measured and ink labelled. At the final laparotomy, around the beginning of oestrus, all ewes were ovariectomized. High ovulation rate was not associated with the total number of antral follicles in any of the breeds. However, there were more follicles greater than 2 mm in diameter in Romanov and Booroola X Romanov crosses (F+) compared to their respective controls. Such a feature was not observed in Finnish Landrace compared to Finn X Blackface and Merino X Blackface ewes. A more numerous population of recruitable follicles, together with a similar incidence of selection through atresia, were the features associated with the high ovulation rate of Romanov compared to Ile-de-France ewes. The high ovulatory potential of the Finn ewes resulted from a markedly reduced incidence of selection through atresia. Booroola X Romanov ewes carrying a copy of the Booroola gene (F+) appeared to possess features of both parental breeds, including high numbers of recruitable follicles, smaller follicular size when recruitment occurs and an extended time for recruitment. Booroola X Romanov (++) ewes, not carrying the gene, appeared to have lost part of the 'Romanov characteristics' of a more numerous population of recruitable follicles. The variability in the kinetics of preovulatory enlargement, seen in these breeds of sheep, demonstrates that there are a number of pathways through which high ovulation rate can be achieved and hence through which ovulation rate might be manipulated.

Animals↗
PubMed1988

Thermoregulation in the female hedgehog, Erinaceus europaeus, during the breeding season.

The body temperatures of 3 breeding and 7 non-breeding female hedgehogs were monitored during 3 years. Lactating females had significantly higher and less variable body temperatures than did pregnant and non-breeding hedgehogs. Breeding females had circadian body temperature cycles that were more biphasic than those of non-breeders. Females maintaining higher mean daily body temperatures showed less variability about the mean than those exhibiting lower mean daily body temperatures. The rate at which body temperatures became more variable as mean daily body temperatures fell was 4.6 times more rapid in non-breeding females than in pregnant and lactating hedgehogs. With the exception of a single female in late gestation, hedgehogs readily became torpid under conditions of low ambient temperature and short photoperiod during summer, particularly when their food intake was restricted.

Animals↗
PubMed1988

Does the first LH surge of the breeding season initiate the first full-length cycle in the ewe?

To determine whether the first LH surge of the breeding season initiates a transient rise in progesterone in most ewes, serum progesterone (daily) and LH (every 4 h) concentrations were measured in samples collected from 7 ewes between 19 July and first oestrus or 8 September, whichever came first. In 6 of the 7 ewes, the first LH surge of the breeding season was followed within 5 days by a transient, 2-day rise in progesterone. Within less than 5 (N = 4), or 9 (N = 1) or 10 (N = 1) days later, a second LH surge occurred, which was similar in maximum amplitude and duration to the first surge, and which initiated the first full-length luteal phase of the breeding season. In the remaining ewe, the first LH surge of the breeding season induced an abbreviated (9 days) and insufficient (maximum progesterone, 0.94 ng/ml) luteal phase. These results demonstrate that most ewes have more than one LH surge before the first full-length luteal phase, the first surge inducing a transient rise in progesterone. Therefore, although the seasonal decrease in response to oestradiol negative feedback is sufficient for initiation of the first LH surge of the breeding season, additional endocrine mechanisms may be necessary to induce the first full-length luteal phase.

Animals↗
PubMedDate not supplied

Gender-related family head schooling and Aedes aegypti larval breeding risk in southern Mexico.

OBJECTIVE: To investigate if family head genre-associated education is related to the risk of domiciliary Aedes aegypti larval breeding in a dengue-endemic village of Southern Mexico. MATERIAL AND METHODS: A family head was considered to have a low education level if he/she had not completed elementary school. To estimate larval breeding risk within each household, a three-category Maya index was constructed using a weighted estimation of controllable and disposable domestic water containers. A socio-economic index was constructed based on household construction characteristics. RESULTS: Low-level education of either family head was associated to higher larval breeding risk. Households with low-educated mothers had more larval breeding containers. These associations persisted after adjusting for household socio-economic level. CONCLUSIONS: These results indicate that households with female family heads with low education levels accumulate more containers that favor Ae. aegypti breeding, and that education campaigns for dengue control should be addressed to this part of the population. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Aedes↗
PubMed2005

[Aedes (Stegomyia) aegypti (Linnaeus, 1762) breeding sites in native bromeliads in Vitória City, ES].

Some insects that are vectors of human diseases have accompanied man in his migrations throughout the world and breed exclusively in the proximity of human dwellings. The mosquito Aedes aegypti has been responsible for epidemics of dengue in Brazil and its presence also constitutes a serious risk for future outbreaks of urban yellow fever. The failure of campaigns to eradicate this species justifies the search for alternative breeding sites, which may be beyond the reach of present control measures. In this study the occurrence of Aedes aegypti breeding sites in native bromeliads on rocky slopes was investigated in five areas of Vitória, capital of the Brazilian State of Espírito Santo, ES. Water contained in the bromeliads was collected with the aid of a suction apparatus to search for culicid larvae. The degree of infestation of buildings in adjacent urban areas was evaluated simultaneously. Culicid larvae were found in bromeliads in four of the five areas investigated, Aedes aegypti being present in two areas. The presence of breeding sites in bromeliads was not related to indices of infestation of buildings in adjacent areas. Further studies are necessary to define whether breeding sites in bromeliads constitute primary foci of Aedes aegypti, or are a consequence of high infestation levels in urban areas.

Aedes↗
PubMed2000

Evaluation of results for Schirmer tear tests conducted with and without application of a topical anesthetic in clinically normal dogs of 5 breeds.

OBJECTIVE: To evaluate, for clinically normal dogs, results of Schirmer tear tests in eyes without topical anesthetic (STT) and to detect differences associated with breed, sex, age, day, and time of day in eyes in which STT was performed after use of topical anesthetic (STTa). ANIMALS: 41 Beagles, 43 Labrador Retrievers, 25 Golden Retrievers, 26 English Springer Spaniels, and 22 Shetland Sheepdogs. PROCEDURE: Beagles had STT and STTa values measured twice daily for 5 days. Client-owned dogs of 4 other breeds had STT and STTa values measured once. RESULTS: Mean +/- SD values of Beagles for STT and STTa were 20.2 +/- 2.5 and 3.8 +/- 2.7 mm/min. Mean values for STT and STTa were as follows: Labrador Retriever, 22.9 +/- 4.1 and 9.6 +/- 3.8 mm/min; English Springer Spaniel; 20.7 +/- 3.2 and 5.4 +/- 3.4 mm/min; Golden Retriever, 21.8 + 3.7 and 8.8 +/- 3.1 mm/min; and Shetland Sheepdog, 15.8 +/- 1.8 and 3.6 +/- 2.8 mm/min. Overall mean values for STT and STTa were 20.2 +/- 3.0 and 6.2 +/- 3.1 mm/min. Differences for STT and STTa were detected among breeds, but significant differences were not associated with sex or age within each breed or in overall values for all dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results for the STT reported here compare favorably with reported values, except for results of Shetland Sheepdogs; however, results for the STTa differ dramatically from reported values. Clinicians should consider effects attributable to breed when evaluating results of STT and STTa in dogs.

Administration, Topical↗
PubMed2002

Spontaneous in vitro contractile activity of specimens from the abomasal wall of healthy cows and comparison among dairy breeds.

OBJECTIVE: To characterize and compare in vitro contractility patterns of sections of abomasal wall harvested from cattle of 3 dairy breeds. SAMPLE POPULATION: Longitudinal and circular smooth muscle preparations harvested from the antrum and body of the abomasum of 30 recently slaughtered Holstein-Friesian, Brown Swiss, and Simmental X Red Holstein cows. PROCEDURE: Spontaneous isometric contractions of specimens in tissue baths of modified Krebs solution were recorded during a 4-hour period. Maximal amplitude, frequency of contractions, and change of basal tension were used to characterize contractility. Statistical analyses were used to test for differences among time periods, among breeds, between specimen locations, and between fiber orientations. RESULTS: Myoactivity patterns of abomasal smooth muscle preparations are highly variable and differ on the basis of location and fiber orientation. Frequency of contractions differed significantly among time periods for longitudinally oriented specimens with decreasing frequencies of contractions over time. Maximal amplitude of the longitudinally oriented specimens from the antrum increased significantly, whereas maximal amplitude of the circularly oriented specimens from the antrum decreased significantly. Values did not differ significantly among breeds. CONCLUSIONS AND CLINICAL RELEVANCE: Patterns of spontaneous contractility of abomasal wall specimens are not homogeneous. During a 4-hour recording period, maximal amplitude and frequency of contractions of specimens varied significantly with respect to orientation and location; however, spontaneous contractile myoactivity did not differ significantly among breeds. Therefore, breed predisposition for displaced abomasum is not correlated with spontaneous activity of smooth muscle specimens.

Abomasum↗
PubMed2005

Testing the usefulness of the molecular coancestry information to assess genetic relationships in livestock using a set of Spanish sheep breeds.

Recent studies have proposed the use of molecular coancestry coefficients as a measure of genetic variability and as a useful tool for conservation purposes. Using simulated data, molecular coancestry has been shown to become constant very quickly after separation of populations, leading to population diversity remaining constant. However, the use of molecular coancestry information to study the genetic relationships between breeds has not yet been widely explored. Here we analyze the polymorphism of 14 microsatellites in 222 unrelated individuals belonging to seven native Spanish breeds to ascertain the usefulness of molecular coancestry-based methodologies in providing information on their genetic relationships. Average kinship distance (D(k)) and average molecular coancestry coefficients (f(ij)) were compared with well-known genetic distances, such as between-breed Reynolds' distance (D(R)), Nei's standard distance (D(s)), and shared allele distance (D(AS)). Kinship distance and f(ij) have moderate to low correlations with the other genetic distances, showing that they provide different information: both D(k) and f(ij) account for the allele frequencies in the founder population, whereas D(R), D(s), and D(AS) characterize the short-term evolution of the populations. Furthermore, D(k) and f(ij) were only moderately correlated (-0.500). The present study used field data to confirm previous research pointing out the ability of molecular coancestry coefficients to assess genetic differentiation of an ancestral origin. In this respect, molecular coancestry-based parameters may be used with classical genetic parameters to obtain information on population dynamics in livestock breeds. This study additionally presents reliable evidence on the history of these sheep breeds.

Alleles↗
PubMed1980

Characterization of cattle of a five-breed diallel. III. Puberty in bulls and heifers.

Pubertal characters of bulls and heifers produced in a diallel mating of Angus, Brahman, Hereford, Holstein and Jersey cattle were analyzed. Ninety-one heifers and 138 bulls in individual pens adn 286 bulls in drylots were fed a 72% TDN diet ad libitum; another 384 heifers were placed on pasture with supplemental feed. Puberty in heifers was defined as time of first ovulatory estrus; in bulls, as first detection of sperm cells in an electroejaculate. Breed type least-squares means, adjusted for birth month, were estimated within sex-nutrition-management groups and then decomposed into breed effects, average heterosis (h), general combining ability (GCA) and specific combining ability (SCA) by diallel analysis techniques. Breed effects were a significant source of variation for all characters studied. Heterosis (h, GCA, SCA) was not significant for pubertal age of bulls or heifers receiving complete diets in pens, a rather high nutritional plane. However, on pasture, crossbred heifers reached puberty at a younger age (P less than .05) than straightbreds. Average heterosis was significant (P less than .05) for increased weight and hip height at puberty and ratios involving these characters for both sexes. Specific combining abilities were not statistically significant for the majority of the pubertal characters, yet large differences among estimates of combining abilities were expressed. Ad libitum feeding of the penned heifers tended to decrease pubertal age and increase pubertal size as compared to pubertal age and size of pastured heifers. The breed type x management interactions within both sexes indicated a different ranking of the breed types for each management regimen.

Animals↗
PubMed1982

Onset of puberty in heifers of diverse beef breeds and crosses.

Puberty traits of straightbred and crossbred heifers (n = 301) were evaluated under pasture conditions. Breed groups represented were straightbred Hereford and Red Poll, reciprocal crosses of these two breeds, Angus X Hereford, Angus X Charolais-Cross, Brahman X Hereford and Brahman X Angus. Breed group was an important (P less than .01) source of variation in heifer weights and in age at puberty. Straight-bred Red Poll and Red Poll cross heifers were youngest at puberty, Angus X Hereford and Angus X Charolais-Cross were intermediate, and straightbred Hereford and Brahman crosses were oldest at the onset of puberty. At the beginning of their first mating season at 19.5 mo of age, 96% of the straightbred Red Polls, 95% of Red Poll crosses, 81% of Angus X Herefords, 89% of Angus X Charolais-Crosses, 68% of straightbred Herefords, 48% of Brahman X Herefords and 74% of the Brahman X Angus had attained puberty. Results of a diallel analysis of Hereford-Red Pool matings indicated that maternal influence of the Red Poll breed was superior (P less than .01) to Herefords for body weight up to 24 mo of age and incidence of puberty at 11.5 mo. Red Polls also exceeded Herefords in direct effects for puberty percentage at 11.5, 15 and 19.5 mo of age. Heterosis was significant for puberty percentage and weight. Breed group differences in pregnancy rate at 24 mo were not significantly.

Animals↗
PubMed1984

Effects of breed and intake level on growth and feed efficiency in ram lambs.

Effects of breed and intake level on growth and feed efficiency in ram lambs were tested with 52 Rambouillet, 46 Dorset and 53 Finnish Landrace (Finn) rams. Rams were individually fed at 100, 85 or 70% of ad libitum or at maintenance. The experimental diet contained 79% digestible dry matter (DM), 3.28% N and 2.95 Mcal metabolizable energy/kg DM. Rams were serially slaughtered every 35 d for 175 d. The efficiency of deposition of body weight, protein, energy and trimmed cuts was determined by breed and intake level over constant time, weight, fat and maturity intervals. Ranking of the breeds for feed efficiency depended upon both the interval and the criterion of evaluation. Efficiency of protein and trimmed cut gain was positively related to mature size in the time and weight intervals, but all differences in efficiency were small in the fat or maturity intervals. Gross energetic efficiency did not differ greatly among breeds in any interval. Dorsets appeared to have a somewhat greater propensity to fatten than the other breeds and to be less able to retain N at a fixed N intake. In the constant time interval, maintenance requirements were estimated to be 115 kcal/kg.75, and the estimated partial efficiencies of energy deposition in fat and protein were .49 and .26, respectively.

Animal Feed↗
PubMed1984

Sow productivity comparisons for four breeds of swine: purebred and crossbred litters.

Data were collected from 366 litters produced in a four-breed (Duroc, Yorkshire, Spotted and Landrace) diallel mating system. Purebred and crossbred litters were farrowed during five consecutive (fall and spring) farrowing seasons (fall 1976 through fall 1978). Litters were produced by randomly mating boars of each breed to at least one female of each breed. Litter size and weight at birth, litter size and weight at 42 d and pig survival to 42 d were analyzed. There were significant parity effects for all traits except survival rate, and significant year and season effects for litter size at birth and 42 d and litter weight at 42 d. Large breed of dam differences were detected for most sow productivity traits. Litters from Spotted females were smaller and lighter in weight. Landrace females were most productive in terms of litter weight at weaning and proportion of their pigs raised from birth to weaning. Breed of sire differences were not significant for any trait. Significant heterosis estimates were obtained for litter size and weight at weaning and for survival rate. Crossbred litters had .79 more pigs, were 11.72 kg heavier at weaning and had a 5.56% greater survival rate than the average of all purebreds.

Animals↗
PubMed1988

Selection on individual phenotype and best linear unbiased predictor of breeding value in a closed swine herd.

Computer simulation of a closed 100-sow and 4-boar swine herd was used to analyze effects of selection method on genetic change, inbreeding and genetic variance over 10 yr for traits with heritabilities (h2) of .10, .30 and .60. Selection of replacement animals was either on individual phenotype or best linear unbiased predictor (BLUP) of breeding value using an animal model. For both methods, culling of existing breeding animals was at random on age and reproductive performance. The effect of additional culling of existing breeding animals when a replacement with better individual phenotype or BLUP of breeding value was available also was evaluated. Genetic gain was greater for selection on BLUP than on individual phenotype, but relative differences narrowed with increasing heritability. At yr 10 the relative advantage of selection on BLUP was 55% for h2 = .10, 25% for h2 = .30 and 10% for h2 = .60. Culling when a replacement with better individual phenotype or BLUP of breeding value was available resulted in considerably increased genetic progress (34% to 57%). The proportional effect of culling on rate of genetic gain was relatively independent of heritability and type of selection. Inbreeding (F) was higher with selection on BLUP (F = .27 to .38 at yr 10) than on individual phenotype (F = .17 to .22 at yr 10). As heritability increased, rate of inbreeding increased for selection on individual phenotype, but rate of inbreeding tended to decrease with increasing heritability for selection on BLUP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed2006

Comparative attractiveness of two chicken breeds to mosquitoes in southern California.

Each transmission season (April-October), mosquito control districts deploy more than 2,000 white leghorn hens as sentinels in California's arbovirus surveillance program. In 2002, Rhode Island red hybrids were used instead, because of insufficient availability of leghorns. Although arboviral seroconversions occurred in both breeds, their attractiveness to host-seeking mosquitoes was not compared. During August and September 2004, Florida Medical Entomology Laboratory traps, each containing 1 hen, were deployed twice weekly at each of 4 fixed locations at a southern California wetland area. The breed at each location was alternated each trap-night to account for intersite variation in the mosquito population. Six chickens of each breed were rotated through the traps to account for interchicken variation in mosquito attractiveness. Although the mosquito counts varied significantly among trap locations, no significant difference was found between the 2 breeds. Sera collected biweekly detected seroconversions to Flavivirus in 4 of 6 red and 1 of 6 white chickens, not a statistically significant difference. Larger sample sizes or experimental infection of different chicken breeds may identify differences in their response to arbovirus infection.

Animals↗
PubMed1992

Inbreeding in Swiss Braunvieh and its influence on breeding values predicted from a repeatability animal model.

Inbreeding coefficients were computed for 910,444 animals of the Swiss Braunvieh population. Of the animals born in 1984, 71.5% were inbred with 67.9, 3.4, and .2% having inbreeding coefficients between greater than 0 and 5%, greater than 5 to 10%, and greater than 10%, respectively. The average inbreeding coefficient was 1.14% but, for animals with both parents and at least one grandparent known, it was 1.67%. Breeding values for total milk, fat, and protein yields and for fat and protein percentages were predicted using a repeatability animal model including a regression on the inbreeding coefficient. Phenotypic performance was sizeably depressed for milk yield only (-26 kg/% of inbreeding or 2.4% of the phenotypic standard deviation). Adjusting for inbreeding increased the estimated genetic trend slightly. Inbreeding is only partially accounted for when it is ignored in the construction of the inverse of the numerator relationship matrix. This effect was investigated by comparing predicted breeding values from a model including the complete matrix with predicted breeding values from a model including a matrix constructed with inbreeding ignored. Only .8% of all predicted breeding values were affected by more than +/- 5.5 kg. The maximum difference observed was 55.3 kg. The observed average absolute differences between the breeding values of offspring predicted with the two models increased with inbreeding of parents.

Animals↗
PubMed2026

Dynamics of Antibiotic Resistance Gene Profiles in Captive Forest Musk Deer (Moschus berezovskii) Along a Breeding Duration Gradient.

BACKGROUND: To conserve wild populations and ensure a sustainable supply of musk, China initiated the captive breeding of forest musk deer. The temporal dynamics of gut antibiotic resistance gene (ARG) profiles in captive forest musk deer along a breeding duration gradient remain poorly characterized. METHODS: In this study, we employed metagenomic sequencing to systematically characterize the profiles and potential mobility of ARGs. Samples were divided into short-term, medium-term and long-term groups according to breeding durations. RESULTS: A total of 331 ARG subtypes and 71 mobile genetic element (MGE) subtypes were annotated across all samples. ARG Shannon diversity differed overall across groups (Kruskal-Wallis, p = 0.03); Bonferroni-adjusted Dunn's test showed no significant pairwise differences. PCoA (Bray-Curtis) demonstrated distinct separation of the ST group (p = 0.002), and shared core ARG subtypes gradually increased with extended breeding years. A strong positive correlation between ARG and MGE abundances was identified (r = 0.85, p = 0.0001). In total, 63 contigs carrying co-localized ARG-MGE complexes were recovered. The ST group contained the highest proportion of such contigs. The ST group displayed tight physical ARG-MGE linkage within 1-3 kb genomic intervals. CONCLUSIONS: Our results reveal that breeding duration is associated with the gut ARG characteristics of captive forest musk deer. Short-term captivity has higher ARG-MGE co-localization, suggesting a higher possibility of mobilization.

One Health↗
PubMed2003

Patterns of Haemoproteus beckeri parasitism in the gray catbird (Dumatella carolinensis) during the breeding season.

We determined the prevalence and intensity of blood parasites in breeding gray catbirds (Dumatella carolinensis) at Killbuck Wildlife Area in Wayne and Holmes Counties, Ohio (USA) from June through August 2000. Of 98 catbirds sampled, 40 (40.8%) had detectable infections of Haemoproteus beckeri. Overall prevalence of H. beckeri in this population is high relative to that reported in earlier blood parasite surveys of both breeding and migrant catbirds. Mean intensity of H. beckeri infection did not vary significantly between young and old birds or among sampling periods. We found no effect of age on prevalence or intensity of H. beckeri infection. Older birds were not more likely to be infected than younger birds, despite longer exposure to arthropod vectors. Prevalence varied significantly with season and was highest in June and lowest in August. This pattern also was observed in older birds sampled repeatedly. This seasonal variation may reflect both newly acquired infections and chronic infections relapsing in response to hormonal changes associated with breeding. Evidence of transmission was observed in the single hatching year bird that lacked detectable infection in early summer, but demonstrated a very high intensity infection in late summer. These observations provide supportive evidence that hematozoa infections are acquired on the breeding grounds during the first year of life and relapse during the breeding season in subsequent years.

Age Factors↗