Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Breeding”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMed1998

Effect of full sibs on additive breeding values under the dominance model for stature in United States Holsteins.

Differences in breeding values between dominance and additive models were examined theoretically and with field data. Data included 5.2 million records on stature from 3.0 million US Holsteins. The largest full-sib family had 29 animals, and 7% of all animals had at least one full sib. The dominance model, which accounted for dominance covariances, included the following effects: management, age, stage of lactation, permanent environment, animal additive, and parental dominance (one-quarter of dominance variance) as well as a regression coefficient for inbreeding percentage. Two reduced models were also assumed; in the first, the parental dominance effect was removed, and, in the second, the inbreeding regression coefficient was also removed. The correlations between breeding values in the three models were > 0.999, but breeding values of some animals from full-sib families changed > 5 standard deviations of parental dominance. The largest changes were observed for parents with large numbers of full-sib progeny, with limited information from parents, and without individual performance records. On average, the differences were up to four times larger for cows than for bulls and up to five times larger for dams than for sires. The greatest differences in breeding values between the dominance and the additive models were observed for dams with full-sib progeny, female full sibs, and low reliability bulls with full sibs in the extended family. Animals with large amounts of additive information as progeny-tested bulls were influenced little by the inclusion of dominance. Animals with a large proportion of information coming from animals with dominance relationships, such as cows originating via embryo transfer changed the most.

Animals↗
PubMed1998

Evaluation of systematic breeding programs for lactating dairy cows: a review.

Observing cows in estrus and inseminating them at the optimum time are necessary steps for effective reproductive management of a dairy herd. However, larger herd sizes can lead to reproductive inefficiency and decreased profits on dairy farms. Synchronization of estrus behavior through pharmacological control has been used to improve reproductive efficiency. Methods of synchronizing estrus were originally devised to decrease the time spent detecting estrus; however, systematic breeding programs are now being used for convenience and efficiency in reproductive management. Systematic breeding programs provide an organized approach for administering artificial insemination (AI) at first service. Moreover, reproductive management is based on a methodical approach for the entire herd rather than for the individual cow. Targeted Breeding (Pharmacia-Upjohn, Kalamazoo, MI) consists of a series of three PGF2 alpha injections at 14-d intervals. For convenience, injections are usually given one day a week to all cows that surpass the specified target date. The PGF2 alpha injections may be continued until detection of estrus and AI or fixed-time AI. Ovsynch consists of a GnRH injection at a random stage of the estrous cycle, followed by PGF2 alpha 7 d later, a second GnRH injection 36 to 48 h after PGF2 alpha, and timed AI. Research has shown that both Ovsynch and Targeted Breeding can improve reproductive performance over that of traditional programs.

Animals↗
PubMed1975

Carcass composition studies. 2. Influences of breed, sex and diet on gross composition of the carcass and fatty acid composition of the adipose tissue.

A study was conducted to determine the effect of breed, sex and diet on the carcass composition of chickens. Male and female chicks of the Light Brahma, White Plymouth Rock, Single Comb White Leghorn, Black Jersey Giant and Dark Cornish breeds were fed three diets of widely varying calorie:protein ratios to four weeks of age. The Black Jersey Giant chickens attained the greatest weight at 4 weeks followed by the White Plymouth Rock, Dark Cornish and Single Comb White Leghorn with the Light Brahma growing the slowest of the strains tested. Significant differences in the quantity of moisture, protein, total lipid and ash present in the total carcass was found among certain breeds. The Light Brahma contained the largest amounts of total lipid, 10.4%, followed by the White Plymouth Rock, 10.2%, Black Jersey Giant, 9.5%, Single Comb White Leghorn, 8.8%, and the Dark Cornish, 8.6%. Both sex and diet also caused differences in the total body composition. Significant differences in the amounts of certain fatty acids in the carcasses of the various breeds were found; however, these differences were not great.

Adipose Tissue↗
PubMed1999

Within-farm variability in number of females mated per week during a one-year period and breeding herd productivity on swine farms.

OBJECTIVE: To determine the effect of within-farm variability in the number of females mated per week during a 1-year period on annual breeding herd productivity in swine breeding herds and to apply statistical process control charts to measures of within-farm variability. DESIGN: Longitudinal study. SAMPLE POPULATION: 84 swine farms with a female inventory of 390 to 1,491 sows and gilts (mean, 761 females). PROCEDURE: As a measure of within-farm variability in a breeding herd, SD for the number of females mated per week during a 1-year period was evaluated. Two types of production records for 84 farms were evaluated. One file contained within-farm variability (SD) in mated females for each farm, and the second included annual productivity 19 weeks after week of mating. We also defined forewarning limits as mean +/- 2 SD, using a statistical process control chart. RESULTS: Larger within-farm variability in number of mated females was associated with lower annual measurements, such as fewer pigs weaned per mated female per year and lower farrowing rate. In addition, farms that did not have any weeks outside the forewarning limits for number of mated females produced more pigs weaned per mated female per year than those with 1 or more weeks of over- or underproduction. Furthermore, the number of weeks outside of forewarning limits was positively associated with within-farm variability in number of mated females. CLINICAL IMPLICATIONS: We recommend that farm managers determine a target range for the number of females mated per week to prevent large week-to-week variations in breeding herd operations.

Animal Husbandry↗
PubMed1999

[Veterinary recommendations for the handling of equine virus arteritis (EVA) in practical breeding care].

The equine virus arteritis (EVA) consistently epidemically varying throughout the different breeds of the horse breeding countries is up to now only of lower significance by means of the typical clinical manifestation as well as an abortion causing factor. The susceptibility of the sexual mature stallions against the equine arteritis virus (EAV) causes different infection response which may lead to some restrictions in their use in natural breeding especially in the artificial insemination. In a certain not precisely predictable part of the stallion population EAV infection will cause a transient or permanent virus presence in the accessorial apparatus of the genital tract with transient or permanent shedding of the virus via seminal secretions. This makes the stallion to one of the dominant factors of the propagation of the field virus. The use of EAV shedding stallions in natural breeding or AI is very risky and only justifiable under certain precautions and additional measurements e.g. in EAV-seropositive or vaccinated mares. A consistent progress in the defeat of the disease can be expected from vaccination of the seronegative stallions with dead or inactivated live vaccines as they are considered to be able to prevent the establishing of EAV shedder status.

Abortion, Veterinary↗
PubMed1999

Breeding soundness examination of North American bison bulls.

OBJECTIVE: To evaluate the breeding soundness examination procedure in plains bison bulls. DESIGN: Multiyear (1993 through 1997) cross-sectional clinical procedure evaluation. ANIMALS: Two hundred thirty-four 28- to 30-month-old bison bulls at Custer State Park. PROCEDURE: Breeding soundness examinations were performed on all bison bulls using 1992 Society for Theriogenology guidelines for beef cattle semen evaluation and reproductive tract examination. Linear and logistic regression analyses were used to detect correlations and associations among breeding soundness examination variables. RESULTS: Scrotal circumference (SC) was significantly correlated with body weight, percentage of normal spermatozoa, percentage of primary spermatozoal defects, and percentage of motile spermatozoa. Scrotal circumference was positively associated with increased odds of semen collection, satisfactory motility (> or = 30% motility), satisfactory morphology (> or = 70% normal spermatozoa), and simultaneous satisfactory motility and morphology. Receiver-operator characteristic curve analysis selected 29 cm as the optimal SC cutoff most predictive of simultaneous satisfactory spermatozoal motility and morphology. Only 36.2% (83/229) of the bison bulls had a SC of 29 cm or greater and satisfactory spermatozoal motility and morphology. CLINICAL IMPLICATIONS: SC is a good indicator of adequate spermatozoal motility and structure in bison. We recommend use of 30% spermatozoal motility, 70% normal spermatozoal morphology, and 29-cm SC as minimal satisfactory measurements for breeding soundness examinations of 28- to 30-month-old bison bulls that have been raised on forage-based nutrition.

Animals↗
PubMed1999

Associations among age, scrotal circumference, and proportion of morphologically normal spermatozoa in young beef bulls during an initial breeding soundness examination.

OBJECTIVE: To evaluate age and scrotal circumference as predictors of semen quality in young beef bulls. DESIGN: Cohort study. ANIMALS: 1,173 beef bulls < 15 months old. PROCEDURE: During initial breeding soundness examination, variables for bulls producing > or = 70% morphologically normal spermatozoa were compared with those for bulls producing < 70% morphologically normal spermatozoa. Mean and 95% confidence interval for age and scrotal circumference were constructed to detect differences between groups of bulls over all observations and within the 5 most common breeds. For these 5 breeds, chi 2 analysis was used to evaluate differences in the proportion of bulls that had values less than the population mean for scrotal circumference, age, and percentage of morphologically normal spermatozoa. Multivariate regression was used to quantify variation in the proportion of morphologically normal spermatozoa that could be explained by age and scrotal circumference. RESULTS: Mean (+/- SD) age and scrotal circumference differed significantly for bulls that produced > or = 70% morphologically normal spermatozoa (12.7 +/- 1.1 months and 35.6 +/- 2.7 cm) and bulls that produced < 70% morphologically normal spermatozoa (12.1 +/- 1.2 months and 34.8 +/- 3.3 cm). The proportion of bulls younger than mean age at first examination and the proportion producing > or = 70% morphologically normal spermatozoa differed among breeds. Age and scrotal circumference explained only 11% of the variation in semen quality. CLINICAL IMPLICATIONS: Among young beef bulls, those that were older and had larger testes were more likely to produce > or = 70% morphologically normal spermatozoa. Age and scrotal circumference were not sufficient predictors of semen quality.

Aging↗
PubMed1976

[Study on different kinds of animal feed for their adequateness for breeding and rearing beagle dogs. 1st communication: summarizing presentation of results (author's transl)].

Some of the current food mixtures for dogs available on the market and their further development were tested regarding the usage under rational and standardized experimental conditions. Further, it should be clarified which of the two separate modes of nutrition has the better effect on breeding and rearing of dogs. The use of a complete feed for breeding and maintaining (Altromin H) was compared with a special breeding feed (Zahn Z) together with a special maintenance feed (Zahn H). The tests were made at two places (Mannheim and Ingelheim) mainly on Beagle dogs. The food mixtures are described with the kind and quantity of the ingredients and nutrients. The results of the parameters measured in breeding effect, nursing period and rearing phase showed that all the feeds tested were nutritively satisfactory to the animals. Detailed information will be given in the 2nd and 3rd communications. Further investigations should be carried out on food consumption, food wastage, optional usage of the ingredients of the foodstuff and on energy balance.

Animal Feed↗
PubMed1999

Breed, sex, and body weight as risk factors for rupture of the cranial cruciate ligament in young dogs.

OBJECTIVE: To describe clinical features of dogs < 2 years old with rupture of the cranial cruciate ligament (CCL) and to evaluate breed, sex, and body weight as risk factors. DESIGN: Case-control study. ANIMALS: 201 dogs < 2 years old with rupture of the CCL and 804 age-matched control dogs. PROCEDURE: Medical records were reviewed for breed, sex, and body weight, and results were compared with results of age-matched control dogs. RESULTS: Breed predisposition was detected for Neapolitan Mastiff, Akita, Saint Bernard, Rottweiler, Mastiff, Newfoundland, Chesapeake Bay Retriever, Labrador Retriever, and American Staffordshire Terrier. Increased risk was detected for neutered males and neutered females, compared with sexually intact males and sexually intact females, respectively. Differences in prevalence of rupture of the CCL were not detected between all males and females, sexually intact males and sexually intact females, or neutered males and neutered females. Body weights of dogs with ruptured CCL were significantly greater than those of control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Several large breeds of dogs are predisposed to rupture of the CCL at a young age.

Animals↗
PubMedDate not supplied

Breeding preferences of Anopheles culicifacies in the rice agro-ecosystem in Kheda district, Gujarat.

Breeding preferences of Anopheles culicifacies, a principle malaria vector, in the plains of India was studied in the rice agro-ecosystem of Kheda district in central Gujarat. Extensive breeding of this species was found in the rice field channels (20.83 per cent) and in rice fields (5.32 per cent). However, rice nurseries (0.91 per cent) and post-harvested rice fields (2.51 per cent) were less preferred. The species was found in abundance in newly transplanted rice fields and during early months of rice cultivation with a peak prevalence in the non-monsoon (Rabi) season. The breeding of An. culicifacies was inversely proportional and negatively correlated (r = -0.868; p < 0.05) with the height of the plants, whereas it showed a positive correlation (r = 0.779; p < 0.05) with the distance between plants. Rice fields near the villages supported maximum breeding of An. culicifacies (48 per cent) followed by the rice fields, 0.5 to one km away from the human habitation. Co-efficient of association (C8 index) revealed a positive association of the species with An. annularis, An. pallidus, An. subpictus and Cx. quinquefasciatus. However, it was negatively associated with An. nigerrimus, Cx. tritaeniorhynchus and Cx. vishnui sub groups.

Animals↗
PubMed2001

[Breed and sex differences in the temperament of calves in a cow-calf operation].

Behavioural traits related to temperament were studied in German Angus (Aberdeen Angus x German dual purpose breeds) and German Simmental cattle. Temperament was defined as the animal's behavioural response to handling. 498 calves (279 German Angus, 219 German Simmental) were tested with two different restrain tests. The animals were tested three times individually during a fixation procedure (days of live: 5, 19, 33) or weighting (days of live: 62, 138, 193). LSQ-means were calculated with a model including breed, year and sex as fixed effects and the sire as a random. Furthermore a regression on the age of the calf was included. Behaviour of the animals were recorded. Significant differences in the recorded parameters were found between the breeds on day 19 and 33 for one test and day 62 for another test. German Angus and male calves were less difficult to handle regarding the different parameters. Both tests could be used to show differences between the breeds.

Age Factors↗
PubMed2001

Effects of birth season, breed, sex, and sire family on cardiac morphology determined in pigs (Sus scrofa domestica) by use of echocardiography.

PURPOSE: Echocardiography played an important role in the screening and diagnosis of hypertrophic cardiomyopathy. In the study reported here, we attempted to evaluate the effects of birth season, breed, sex, and sire family on cardiac morphology determined in pigs by use of echocardiography. METHODS: A total of 411 pigs (mean body weight and age of 105.7 +/- 10.6 kg and 214.4 +/- 25.5 days, respectively) with different genetic backgrounds (Landrace, Yorkshire, and their two-way crossbred) were studied. Cardiac morphologic measurements included thickness of left ventricle and interventricular septum at end-systolic and end-diastolic phases. Meanwhile, the statistical model included the following effects: birth season, breed, sex, interaction between breed and sex, sire family, body weight, and age. RESULTS: Mean cardiac morphologic measurements were as follows: thickness of the interventricular septum at end-systolic and end-diastolic phases was 1.74 and 1.14 cm, respectively; and thickness of the left ventricular free wall at end-systolic and end-diastolic phases was 1.81 and 0.98 cm, respectively. Medium positive correlations existed among the cardiac morphologic measurements r = 0.31 to 0.53; P < 0.001). Pigs born in spring had significantly (P < 0.05) lower cardiac thickness at the end systolic phase than did pigs born in other seasons, and Landrace pigs had higher cardiac morphologic measurements than did Yorkshire and two-way crossbred pigs. Additionally, thickness of interventricular septum at the end-diastolic phase in male pigs was significantly higher than that in female pigs (P < 0.05). Cardiac morphologic measurements for the sire family were significantly (P < 0.05) different, and contributed 77.2 to 87.9% of the total variation, suggesting that genetic variation in cardiac morphology might exist in pigs. CONCLUSIONS: Cardiac morphology of pigs might be influenced by genetic background. The effects of birth season, breed, sire family, and sex should be adjusted when using pigs as an animal model for comparative cardiovascular studies.

Animals↗
PubMed1999

Staying good while playing god--the ethics of breeding farm animals.

Modern genetics has given us some very efficient tools with which to alter the characteristics of animals. To date, farm animal breeders have mainly used these tools to increase productivity. Thus, each new generation of farm animals matures faster, yields more milk, or produces more meat or eggs, than the previous one. Despite these apparent benefits, modern farm animal breeding has had severe negative consequences, including effects on the quality of the animals' lives and biodiversity. The aim of this paper is to discuss the goals and consequences of farm animal breeding within an ethical context. First, a description of what has happened to broilers and dairy cattle as breeders have pursued the goal of ever more efficient production is given. Second, the ethical values that ought to underlie future breeding schemes are discussed. It is suggested that there are in fact two very different ethical approaches: the 'quality of life-based' approach and the 'preservationist' approach. A view combining elements from both approaches is advanced. Finally, an example is given of how it is possible, in practice, to pursue an ethically defensible breeding goal without compromising production efficiency.

Animal Welfare↗
PubMed2002

The impact of molecular markers on the wheat breeding paradigm.

We briefly review the limited application of marker assisted selection in past wheat breeding programmes, and contrast the current situation, where increasingly it has become feasible to tag almost any gene with a microsatellite assay. Although this capability is having an impact on the conduct of large breeding programmes, a much more profound change in breeding strategy will become possible when SNP technology has matured sufficiently so that the throughput of molecular marker-based genotyping will be able to keep pace with the numbers of plants that breeders can handle in the field. We discuss the considerations that will need to be addressed in the generation of a new breeding paradigm to take advantage of the genomics revolution.

Breeding↗
PubMed2002

Potential signals mediating the maintenance of reproductive activity during the non-breeding season of the mare.

The seasonal nature of reproductive activity in mares is widely accepted and considerable attention has focused on the mechanisms that lead to the initiation of the breeding season. In contrast, considerably less information is available about the termination of the breeding season. It is interesting to note that each winter a sub-population of mares continues to undergo oestrous cyclicity during the non-breeding season. Continuation of reproductive activity during the winter occurs most frequently in mares that maintain a non-pregnant condition in successive years. The maintenance of a non-pregnant condition in successive years leads to an increase in the percentage of total body fat and it has been proposed that the degree of adiposity may be a determinant of reproductive activity during the winter months. To investigate this hypothesis we have manipulated fat stores by either pharmacological treatments or feed restriction. The studies described in this review demonstrate that manipulation of body fat during the autumn months fails to modify the mechanisms that lead to anoestrus or the proportion of mares that continues to show oestrous cyclicity during the winter months. On the basis of these and related studies two hypotheses are presented that may serve as a template for future work. The first hypothesis proposes that one aspect of the long-term regulation of seasonal reproductive rhythms in mares, specifically anoestrus, may reflect recognition of the availability of metabolic fuels before perception of a change in photoperiod. Alternatively, energy availability may need to reach a critical value before a presumptive inhibitory daylength signal initiates termination of the breeding season. This review describes previous and current studies that have led to development of these proposals.

Adipose Tissue↗
PubMed1992

Intradomestic mosquito breeding sources and their management.

Seven mosquito species were found to breed in intradomestic breeding sources. An. stephensi and An. subpictus bred in almost all types of containers. Among the culicines, Cx. quinquefasciatus and Ae. aegypti were predominant. Larval breeding was controlled through source reduction or introduction of larvivorous fish Poecilia reticulata. Health education helped in acceptance of the programme by the community. Intradomestic breeding positivity was 2-6% and 16-31% in experimental and control areas respectively.

Aedes↗
PubMed2003

[Behaviors time budget and daily rhythm of great bustard in breeding season].

The direct observation method was adopted to study the breeding behaviors time budget and daily rhythm of wild great bustard (Otis tarda) on the grassland of Southeast Keyouqianqi in Inner Mongolia Municipality during the period from April to July in 2000 and 2001. The results showed that the behaviors time budget of great bustard were regularly in some degree, and there exited differences between male and female. The behaviors changed with the changes of activity space, food conditions and breeding stages. During breeding prophase, great bustard spent its time mainly on feeding, relaxing, walking and observing, and the male and female spent 87% and 93% of the time on the 4 behaviors, respectively. The time budget and intensity of male and female changed greatly during the breeding anaphase. The great bustard had a daily rhythm on feeding, relaxing and displaying, and there were two peaks on feeding and displaying. The great bustard spent most time on relaxing.

Animals↗
PubMed2004

[Implementation of paragraph 11b of the German Animal Welfare Act on the basis of the so-called "Quality Breeding" Report].

Enforcement of paragraph 11b of the German Animal Welfare Act is a responsibility of breeders and their organisations as well as executive local authorities. The Report on Defective Breeds of the Federal Ministry of Agriculture describes numerous breeding traits which are in conflict with animal welfare and gives valuable information for fancy or pet breeding. Yet a selection has to be made for taking legal actions, following specific criteria. With four examples different cases are presented, each requiring a different approach by the veterinarian authorities. Court decisions in Hessen concerning bans on breeding white cats and crested ducks show that the paragraph 11b is executable.

Animal Welfare↗