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At least 1,423 records · Page 79Linked to original sources
PubMed1977

Effects of geographic transfer on the timing of seasonal breeding of rhesus monkeys.

This is a study of the effects of geographic transfer on the timing of seasonal breeding of free-living rhesus monkeys on Cayo Santiago and La Parguera islands in Puerto Rico. The results demonstrated a progressive shift in the breeding season of the transferred group. The full shift required a period of 2 years. Change from one environment to another produced shifts in onset of estrous. The explanation for this phenomenon proposes an interaction between the specific reproductive state of the female, which may or may not be sensitive to a particular environmental change, and the environmental variation which is correlated with onset of breeding.

Animals↗
PubMed1980

Persistent adrenocortical activation in female rhesus monkeys after new breeding groups formation.

Persistent elevated adrenocortical responsiveness to ACTH has been demonstrated in female rhesus monkeys as long as 13 weeks after relocation into new single male breeding groups. Measures of immediate responses to psychosocial stress of grouping such as aggressive interaction and circulating plasma cortisol levels were highest immediately after grouping, but tended to decline to lower levels after the first month. In a retrospective comparison of such 'new' breeding groups (less than one year) versus established breeding groups (more than two years), stress-related morbidities such as trauma (wounding) and loose stools were higher for as long as six months after new group formation. The actual and potential adverse effects of regrouping stress on colony health and reproduction are relevant to cost-benefit assessment of such colony management procedures.

Adaptation, Psychological↗
PubMedDate not supplied

A sampling method for estimating the accuracy of predicted breeding values in genetic evaluation.

A sampling-based method for estimating the accuracy of estimated breeding values using an animal model is presented. Empirical variances of true and estimated breeding values were estimated from a simulated n-sample. The method was validated using a small data set from the Parthenaise breed with the estimated coefficient of determination converging to the true values. It was applied to the French Salers data file used for the 2000 on-farm evaluation (IBOVAL) of muscle development score. A drawback of the method is its computational demand. Consequently, convergence can not be achieved in a reasonable time for very large data files. Two advantages of the method are that a) it is applicable to any model (animal, sire, multivariate, maternal effects...) and b) it supplies off-diagonal coefficients of the inverse of the mixed model equations and can therefore be the basis of connectedness studies.

Algorithms↗
PubMed2005

Mortality in over 350,000 insured Swedish dogs from 1995-2000: II. Breed-specific age and survival patterns and relative risk for causes of death.

This study continues analysis from a companion paper on over 350,000 insured Swedish dogs up to 10 years of age contributing to more than one million dog-years at risk during 1995-2000. The age patterns for total and diagnostic mortality and for general causes of death (trauma, tumour, locomotor, heart and neurological) are presented for numerous breeds. Survival estimates at five, eight and 10 years of age are calculated. Survival to 10 years of age was 75% or more in Labrador and golden retrievers, miniature and toy poodles and miniature dachshunds and lowest in Irish wolfhounds (91% dead by 10 years). Multivariable analysis was used to estimate the relative risk for general and more specific causes of death between breeds accounting for gender and age effects, including two-way interactions. Older females had tumour as a designated cause of death more often than males in most breeds, but not in the Bernese mountain dog. Information presented in this and the companion paper inform our understanding of the population level burden of disease, and support decision-making at the population and individual level about health promotion efforts and treatment and prognosis of disease events.

Age Factors↗
PubMed1976

Breeding and fertility of the Egyptian spiny mouse, Acomys cahirinus: effect of different environments.

2 years experience with Acomys in one laboratory confirmed the slow breeding rate found by other workers. On moving the animals to another laboratory there was a 2-5 fold increase in breeding rate. The most likely explanation of this change was the presence of copper in the drinking water at the 1st laboratory, due to the use of copper water pipes. The data relating to maintenance and breeding of acomys for 2 years at the 2nd laboratory were analyzed to provide a more representative picture of the species.

Animals↗
PubMed1989

Housing, breeding and selecting chickens of the Obese strain (OS) with spontaneous autoimmune thyroiditis.

A management programme is described for a small colony of Obese strain (OS) chickens afflicted with spontaneous hereditary thyroiditis. Animals of this White Leghorn line are used as an animal model for Hashimoto's thyroiditis of man to study possible mechanisms of autoimmunity in general and organ-specific autoimmune diseases in particular. Due to the severe mononuclear cell infiltration of the thyroid glands, OS chickens show symptoms of hypothyroidism, including small body size, subcutaneous and abdominal fat deposits, long silky feathers, small combs and wattles, cold sensitivity, low fertility and poor hatchability. Successful breeding of this line, especially in a small population, can therefore be done only if rigid precautions are taken in aspects of animal care. The selection of breeding stock, the principal requirements for adequate housing and food, the artificial insemination procedure, and recommendations for collecting and incubating chicken eggs are reported in detail. Precautions necessary during the incubation of fertilized eggs, and fertility and hatchability are reported. During the hatching period several specific features must be considered. The important role of staff involved in a small chicken breeding unit is emphasized.

Animal Husbandry↗
PubMed2004

Effects of organochlorine contaminants on thyroid hormone levels in Arctic breeding glaucous gulls, Larus hyperboreus.

Studies on glaucous gulls (Larus hyperboreus) breeding in the Barents Sea have reported that high blood levels of halogenated organic contaminants in this species might cause reproductive, behavioral, and developmental stress. However, potential endocrine system modulation caused by contaminant exposure has yet not been reported in this Arctic apical predator. In this present study we aimed to investigate whether the current levels of a selection of organochlorines (OCs) were associated with altered circulating levels of thyroid hormones (THs) in free-ranging adult glaucous gulls breeding at Bear Island in the Barents Sea. Blood concentrations of 14 polychlorinated biphenyls, hexachlorobenzene (HCB), oxychlordane, and p,p' -dichlorodiphenyldichloroethylene (p,p' -DDE) were quantified, in addition to free and total thyroxine (T4) and triiodothyronine (T3), in plasma of 66 glaucous gulls in the spring of 2001. Negative correlations were found between plasma levels of T4 and T4:T3 ratio, and blood levels of OCs in male glaucous gulls. Despite their relatively low contribution to the total OC fraction, HCB and oxychlordane were the most prominent compounds in terms of their negative effect on the variation of the T4:T3 ratio. Moreover, lower T4 levels and T4:T3 ratios were measured in glaucous gulls breeding in a colony exposed to high levels of OCs, compared with a less exposed colony. Levels of T3 were elevated in the high-OC-exposed colony. This may indicate that the glaucous gull is susceptible to changes to TH homeostasis mediated by exposure to halogenated organic contaminants.

Animals↗
PubMed2005

Factor XI mutation in a Holstein cow with repeat breeding in Japan.

Factor XI deficiency is an autosomal recessive coagulopathy in Holstein cattle. Affected cows have a tendency to show repeat breeding. Forty repeat breeding Holstein Friesian cows were selected and tested for the Factor XI mutation. Genomic DNA was isolated from the blood of the cows (n=40). Exon 12 of the Factor XI gene of the cows was amplified by PCR. One repeat breeding cow was heterozygous to the Factor XI mutation as indicated by the presence of two DNA fragments of 320 bp and 244 bp. The insertion of the 76 bp in the heterozygous cow was confirmed by DNA sequencing. The heterozygous cow was in her fourth lactation. She gave birth to male twins at the last calving. She was inseminated artificially four times after the last calving. Factor XI deficiency in cattle has been reported in different countries. However, no case was reported in Japan. This might be the first to report Factor XI mutation in Holstein cattle in Japan.

Animals↗
PubMed2005

Prevalence of Giardia intestinalis infection in dogs of breeding kennels in Japan.

Giardia intestinalis antigen in fecal samples was examined in 361 dogs of 14 breeding kennels located at various areas in Japan, using a commercial enzyme-linked immunosorbent assay (ELISA) kit. G. intestinalis antigen was detected in 37.4% of the fecal specimens. All of the 14 breeding kennels were positive for G. intestinalis antigen with the range from 6.7 to 59.3%. The prevalence in puppies (54.5%) was significantly (p < 0.01) higher than that in adults (30.9%). There was no difference in prevalence between males and females, and between the puppies from the mother dogs positive and negative for Giardia antigen. In conclusion, G. intestinalis widely invaded the breeding kennels in Japan.

Age Factors↗
PubMed1984

Plasma gonadotrophin concentrations during the oestrous cycle and after ovariectomy in two breeds of sheep with low and high fecundity.

LH and FSH concentrations were measured during the oestrous cycle in two local Moroccan breeds of sheep with low (Timahdite: 1 CL/cycle) and high (D'man: 3 CL/cycle) ovulation rates. Twenty ewes were used from each breed and blood was collected at 3- or 6-h intervals from 5-4 days before oestrus up to Day 14 of the new cycle, when 4 D'man and 4 Timahdite ewes were ovariectomized. After surgery, blood sampling was continued at 6-h intervals for 2 weeks. (1) The mean basal concentration of LH, the maximum value of the preovulatory LH surge and the area under the curve were significantly higher (P less than 0.05) in Timahdite than in D'man ewes. (2) The pattern of FSH in each breed showed no clear basal level but a periodic succession of peaks with variable amplitudes. The first and highest peak corresponded with the preovulatory LH surge. The 2nd peak followed immediately after the first peak and reached its maximum 24-30 h later. The 3rd peak was flatter and occurred around Day 6 of the cycle. The 4th peak was observed around Day 10 of the cycle and showed the lowest amplitude. The 5th and last peak occurred 66-87 h before the next preovulatory surge. (3) FSH concentrations were higher in the prolific D'man than in Timahdite ewes around the time of oestrus (pro-oestrous peak, preovulatory surge and the 2nd peak). The drop in FSH concentrations observed in D'man ewes before the preovulatory surge was more pronounced and started later.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Oestrous cycle and breeding season of farmed fallow deer, Dama dama.

Oestrus was detected on 177 occasions in 34 fallow does for the duration of the breeding season. A total of 142 cycles had a mean length of 22.4 (+/- 1.3, s.d.) days. Cycle length increased and became more variable as the season proceeded but was not affected by doe age or liveweight. First oestrus occurred within a 12-day period, but the length of the breeding season, and therefore the number of oestrous cycles, was related to doe age. Serum progesterone profiles suggest that silent ovulations, associated with short-lived corpora lutea, occurred before the first behavioural oestrus. Ovulations without oestrus may have also occurred at the end of the breeding season.

Aging↗
PubMed1982

[Breeding and rearing of Japanese field voles (Microtus montebelli Milne-Edwards) and Hungarian voles (Microtus arvalis Pallas) as new herbivorous laboratory animal species].

Microtus species are very useful as experimental small animals with herbivorous characteristics. In this report, to approach establishment of the use of Japanese field voles (M. montebelli) and Hungarian voles (M. arvalis) as experimental animals, the biological characteristics, breeding methods and reproductive performance of these animal species were comparatively investigated. The number of chromosomes of M. arvalis is 12n = 46, differing from those of M. montebelli, 2n = 30. The breeding and reproduction of the Microtus species were relatively easily accomplished in the laboratory, by giving high fiber-containing rations. These animals prove to be polyestrous and showed postpartum estrous on the day of parturition. In the breeding by the continuous mating of the same pair, there was little or no delay in implantation due to lactation, especially in M. arvalis resulting in continuous birth at intervals of 20 to 21 days. On examination of vaginal smears, Japanese field voles (M. montebelli) did not show any definite pattern whereas 23 out of 30 voles from Hungary (M. arvalis) examined showed 6- to 18-day cycles. There were remarkable differences between the Japanese voles and the Hungarian voles, both biologically and reproductively.

Age Factors↗
PubMed1983

Treatment and improvement of the breeding system of the albumin-deficient and jaundiced strain of rats.

The AJR (alb/alb, j/j) strain is semi-lethal and the rats die at about two weeks of age. Cross breeding with a pari of ACJ (alb/alb, j/+) is required for maintenance and production. We studied the treatment of AJRs for improvement of the breeding system. AJRs with jaundice on the skin at about 7 days of age were intraperitoneally administered 1 ml/rat of normal rat serum every few days and irradiated with visible light for 14 hours a day in an irradiation box. This treatment allowed us to obtain mature AJRs. The treatment was effective when applied for short periods of 1-4 weeks of age. The frequency of maturation of the treated AJRs was about 27% and the best mating combination was a female ACJ and male AJR. The treatment of AJRs, made the progeny test for the selection of ACJs for breeding pairs of ACJ X ACR unnecessary and increased the frequency of appearance of AJRs to 50%.

Animals↗
PubMed1981

Importance of variations in behavioural and feedback actions of oestradiol to the control of seasonal breeding in the ewe.

Seasonal variations in the behavioural and feedback actions of oestradiol in the ewe were examined by determining the ability of various physiological oestradiol concentrations to elicit oestrous behaviour, induce an LH surge, and suppress tonic LH secretion at four times of the year. These tests were performed in acutely ovariectomized animals pretreated with oestradiol and progesterone to minimize seasonal differences in their endocrine status. Although smaller amplitude LH surges were observed in anoestrus, the dose-response curves for the induction of LH surges were virtually identical at all times of the year. Oestradiol was slightly less effective in eliciting oestrous behaviour in anoestrus and during the transition to the breeding season than at other times. This seasonal variation was, however, observed only with relatively low oestradiol concentrations; serum oestradiol levels of 3 pg/ml or greater induced oestrus in almost all ewes regardless of season. In contrast, there was a marked seasonal change in the negative feedback action of oestradiol. In anoestrus, basal oestradiol levels of 1-3 pg/ml suppressed LH to low levels (0.3 ng/ml), whereas in the breeding season, even peak oestradiol concentrations of 10 pg/ml were not able to produce this degree of inhibition. These results thus support the hypothesis that the annual breeding cycle of the ewe is governed primarily by shifts in the extent to which oestradiol can suppress tonic LH secretion.

Animals↗
PubMed1986

Induction of ovulation during anoestrus in two breeds of sheep with multiple injections of LH alone or in combination with FSH.

The gonadotrophic requirements for the induction of ovulation and formation of a viable corpus luteum in two breeds of seasonally anoestrous sheep of differing fecundity was investigated. Welsh Mountain (n = 20) and Damline ewes (n = 19) were given LH or FSH either alone or in combination. Luteinizing hormone was injected i.v. at an increasing frequency for 72 h (one injection every 3 h for 24 h, one every 2 h for 24 h, and one every hour for 24 h) and FSH was injected in an identical manner for the first 36 h of treatment. Exogenous LH alone and in combination with FSH induced a preovulatory LH surge in all 19 ewes and ovulation in 18 out of 19 ewes of both breeds. However exogenous FSH alone was ineffective. The incidence of normal corpus luteum function in ewes induced to ovulate was low and not related to treatment, timing or magnitude of the LH/FSH surge. It is concluded that in both breeds studied it is the infrequency of LH pulses which limits the development of preovulatory follicles during seasonal anoestrus, that the requirement for FSH remains unknown, and that the induction of inadequate corpora lutea during seasonal anoestrus reflects either defects in hormonal priming of the preovulatory follicle and/or inappropriate luteotrophic support after ovulation.

Anestrus↗
PubMed1987

Changes in plasma concentrations of LH, FSH and prolactin in ewes receiving melatonin and short-photoperiod treatments to induce early onset of breeding activity.

Breeding activity was similarly advanced in ewes given continuous (s.c. implant) or timed (oral dose at 15.30 h) melatonin treatments or subjected to a short (8 h light: 16 h darkness) artificial photoperiod. Treatments commenced in mid-June and were terminated in mid-November. Weekly and serial blood samples were collected before and after treatments commenced, to ascertain the effects on plasma prolactin, LH and FSH concentrations. In addition, serial blood samples were collected for 24 h plasma prolactin and melatonin estimations before and after cessation of the treatments. Plasma prolactin levels were significantly reduced immediately following the start of the melatonin (implant and oral) and short-photoperiod treatments but 'rebounded' to levels greater than control values. The normal seasonal (spring) rise in plasma prolactin was noted in the following year. Before the onset of breeding activity, mean plasma LH and FSH concentrations and LH pulse frequency did not change following any of the treatments. The 24-h plasma melatonin profile accurately reflected the various applied treatments but had re-entrained to the prevailing (natural) photoperiod 1 week after termination of the treatments. There were no significant group differences in 24-h plasma prolactin levels 1 week before or 1 and 11 weeks after the treatments had ceased. Such treatments, although successfully advancing the onset of breeding activity and modifying the seasonal plasma prolactin rhythm, were not manifested through any apparent change in peripheral LH or FSH.

Animals↗
PubMed1998

Breeding for disease resistance in Merino sheep in Australia.

Breeding for disease resistance in Merino sheep in Australia has attracted considerable research and development attention. Increased labour costs, the reduced efficacy of common anthelmintics and insecticides, consumer demand for products which are free of chemicals and the poor prognosis of alternative long-term control strategies are all forcing sheep breeders to contemplate the best animal health options available, including selective breeding for resistance. The three major diseases which affect sheep production include gastrointestinal nematode parasites, flystrike (cutaneous myiasis) and footrot. Genetic improvement has been shown to be feasible in all these diseases, possibly with little adverse effect on genetic progress in other production traits. Programmes for resistance to internal parasites to be included in practical breeding programmes are now in progress. This paper deals with the incentives for focusing on the three major diseases in Merino sheep, the potential sources of genetic variation, and the means to exploit these sources of variation. The authors also highlight gains and benefits achieved in experimental selection flocks, and the difficulties and options available for commercial breeders.

Animals↗
PubMed1998

Conventional breeding programmes and genetic resistance to animal diseases.

The power of selection is illustrated by the increase in the average annual yield of dairy cows in Sweden in kg fat-corrected milk from 2,500 kg in the year 1900 to 8,200 kg in 1997. More than a half of this improvement has a genetic origin. The breeding goal for dairy cattle has successively been broadened to cover traits other than production. The prerequisites for a successful breeding programme and the consequences of the process are presented in this article. The dramatic improvement of the reproduction techniques and statistical tools for genetic evaluation of breeding stock and selection, which have occurred during the last 50 years, is also discussed. The factors which affect the genetic gain are described in detail to demonstrate the possibility of making genetic gains in traits reflecting disease resistance. The Swedish procedure of disease recording and the procedures for genetic evaluation of fitness traits, such as disease resistance and female fertility, are described. The existence and consequences of negative genetic correlations between production and fitness traits are dealt with, as is the procedure for multi-trait selection. An illustration of methods for performing multi-trait selection in real life, and the consequences of such selection in an envisaged Nordic selection scheme, are given. Finally, the authors review the present genetic trends for fitness traits of dairy cows in Sweden.

Animals↗