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Genetic And Environmental Factors Affecting Litter Size In Swine
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Book Synopsis Genetic and Environmental Factors Affecting Litter Size in Swine by : Missouri-Columbia. Agricultural Experiment Station
Download or read book Genetic and Environmental Factors Affecting Litter Size in Swine written by Missouri-Columbia. Agricultural Experiment Station and published by . This book was released on 1956 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Some Genetic and Environmental Factors Affecting Litter Size in Swine by : Vaithilingam Rathnasabapathy
Download or read book Some Genetic and Environmental Factors Affecting Litter Size in Swine written by Vaithilingam Rathnasabapathy and published by . This book was released on 1956 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Genetic and Environmental Factors Affecting Litter Size in Swine by : V. Rathnasabapathy
Download or read book Genetic and Environmental Factors Affecting Litter Size in Swine written by V. Rathnasabapathy and published by . This book was released on 1956 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Genetic and Environmental Influences Upon Litter Size and Variation of Birth Weights in Berkshire Swine by : Verne Merrill Chapman
Download or read book Genetic and Environmental Influences Upon Litter Size and Variation of Birth Weights in Berkshire Swine written by Verne Merrill Chapman and published by . This book was released on 1963 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Litter site and birth weight data compiled from the farrowing records of 275 litters out of 109 purebred Berkshire sows of the Oregon State University swine herd during the years 1953 to 1960 inclusive were used in this study. Genetic and environmental factors influencing four components of reproductive performance, namely, within litter variance of birth weights, litter size, number born dead and mean birth weight of pigs within a litter were evaluated by the method of stepwise multiple regression analysis. The estimate of within litter variance of birth weight was greater for larger litters but was decreased as the inbreeding coefficient of the litter increased. Litter size was depressed as inbreeding of dam increased; however, due to the structure of the herd there was an unusual positive relationship between inbreeding of litter and litter size. The latter observation leads to the conclusion that litter size is more strongly influenced by the genotype of the sow than by the genotype of the offspring. The number born dead in a litter increased as litters became larger. A disproportionate number of highly productive sows kept in the herd to advanced ages brought about an unusual ace-of-dam effect; there was, however, no basis for establishing that a greater number of dead pigs occurred in litters out of sows of different ages. The average birth weights of pigs within litters was smaller in larger litters. Average, birth weight was also decreased as the inbreeding of dam increased. Age-of-dam effects were not found to be important for any of the components of reproductive performance studied nor were consistent environmental effects found. An analysis of variance of sib groups was used to derive estimates of repeatability and heritability for within litter Variance of birth weights, litter size and litter weight. Data for these analyses were taken from the farrowing records of 44 scars which had farrowed two or more litters. The estimates of repeatability of within litter variance of birth weights was 0.02. This indicates that there was no tendency for sows to exhibit permanent differences for this character. The repeatability estimates of litter size and litter weight were 0.208 and 0.135 respectively. The heritability estimates of litter size as derived from the dam and sire component of the covariance of half sibs were 0.198 and 0.237. The estimate of heritability of litter weight at birth was 0.199. From these estimates it appears that progress from selection for improvement in all of the components of reproductive performance would be slow. An increased rate of progress will require a more accurate identification of superior genotypes Which can be accomplished, in part, by stabilizing temporary environmental factors.
Book Synopsis Some Genetic and Environmental Factors Affecting Performance and Carcass Measurements in Swine by : David Tupper Spurr
Download or read book Some Genetic and Environmental Factors Affecting Performance and Carcass Measurements in Swine written by David Tupper Spurr and published by . This book was released on 1969 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data from 592 litters of pigs farrowed and raised at the Oregon Agricultural Experiment Station at Corvallis from the spring of 1961 through the spring of 1968 were analyzed for effects of year and season of birth, breed, sex, inbreeding and age of dam on measures of fecundity, growth rate and carcass merit. Hierarchal analysis of variance was done to find the effects of population structure and inbreeding on the components of phenotypic variance and heritability for measures of litter size and average daily gain. The Oregon State University swine herd is composed of a partly closed line of Berkshires, a partly closed herd of Yorkshires, reciprocal crosses between these two breeds and a line developed from inter-se mating of F1 and later generations. Significant differences among the various breed groups were found for number of pigs born alive, number born alive plus dead, number born plus mummified fetuses, number weaned per litter, average daily gain, carcass length, average backfat thickness, loin eye area and ham weight. Differences among breeds were not significant for loin weight. The level of performance did not increase, over the period studied, for any of the traits studied except loin eye area. The lack of increase in level of performance may be due to a lack of sufficient selection pressure, detrimental environmental effects or the depression in performance due to inbreeding. Fall-farrowed pigs had lower average daily gains than spring-farrowed pigs but, in general, had more desirable carcasses. The differences in performance and carcass traits are attributed to the smaller proportion of males performance tested from fall-farrowed litters. Males gained 0.096 pounds per day faster than females but carcasses were 0.264 inches shorter, had 0.067 inches more average backfat, had ham and loin weights that were 0.798 and 0.516 pounds less respectively and had loin eye areas that were 0.382 square inches smaller. Negative regressions for the effects of inbreeding of the dam on litter size at birth and weaning and positive regressions for the effect of inbreeding on litter size at birth were found but most effects were not statistically significant. The number of mummified fetuses and stillbirths was not affected by inbreeding but mortality between birth and weaning increased significantly when inbreeding of the dam rose above a threshold of ten percent. Both linear and quadratic components of age of dam had highly significant effects on the litter size at birth and on the number of pigs weaned with a peak in sow productivity occurring at about three years of age. Age of dam effects were thought to be due almost entirely to differences in ovulation rate or early embryo survival as the number of mummified fetuses, stillbirths or pre-weaning deaths were not related to age of dam. Environmental variation of litter size and average daily gain increased with increasing levels of inbreeding, indicating that inbred individuals were unable to buffer themselves against fluctuations in environment. Heritability of average daily gain decreased with inbreeding because of lower genetic variance and higher environmental variance. Heritability estimates of litter size were quite variable due to the limited number of sire groups available but, in general, were quite low and generally not significantly different from zero. Estimates of heritability of average daily gain were more than twice as high as most estimates reported in the literature. These high estimates were thought to be biased due to the cumulative effects of a number of characteristics of the population and of the data. A line developed from a Berkshire-Yorkshire crossbred foundation should have more alleles segregating and therefore should have a higher additive genetic variance than the parental breeds. However, no differences between breed groups were observed in the magnitude of genetic variance, environmental variance or heritability estimates.
Book Synopsis Genetic and Environmental Aspects of Litter Size in Swine by : Willard Edward Urban
Download or read book Genetic and Environmental Aspects of Litter Size in Swine written by Willard Edward Urban and published by . This book was released on 1963 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Genetic Parameters for Litter Size in Pigs by : Zoran Lukovic
Download or read book Genetic Parameters for Litter Size in Pigs written by Zoran Lukovic and published by LAP Lambert Academic Publishing. This book was released on 2010-11 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Litter size is one of the most important traits in overall reproductive efficiency of breeding sows. The triat has low heritability, is measured only in females and is expressed relatively late. Genetic improvement for litter size is possible due to large enough direct additive genetic variance, the availability of records on many relatives and short generation interval. Litter size is affected by many environmental and genetic factors and interaction between them. The goal of this study was to determine covariance functions for litter size i.e. number of piglets born alive using random regression model. Further, the aim was to compare it with estimates of genetic components obtained by using repeatability and multiple-trait model.
Book Synopsis Effectiveness of Selection for Productive Characteristics in Developing the Montana No. I Hogs by : Wesley Charles McEwen
Download or read book Effectiveness of Selection for Productive Characteristics in Developing the Montana No. I Hogs written by Wesley Charles McEwen and published by . This book was released on 1952 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important productive characteristics of hogs is reproductive efficiency. Reproductive efficiency is best measured by litter size at weaning. Litter size at birth and weight of the pigs at birth are among the most important factors affecting litter size at weaning. It has been demonstrated that less than 5 per cent of pigs weighing 1.5 pounds or less at birth survive to be weaned. It was the purpose of this study to determine the selection for litter size and birth weight of the pigs and the effects of this selection on subsequent generations during the development of the Montana No. 1 line of hogs. The data for this study were made available through the agencies cooperating in the development of the Montana No. 1 hogs, the Montana Agricultural Experiment Station and the Bureau of Animal Industry, United States Department of Agriculture. To facilitate comparisons between generations all litters farrowed by sows which were her second or third litter were eliminated from the study. A significant difference between the average birth weight of pigs of gilts whose dams were gilts and the average birth weight of pigs of gilts whose dams were sows was determined by analysis of variance. The pigs farrowed by gilts by sows were heavier. All spring litters farrowed by gilts by gilts were used in the study from farrowing records taken from 1939 to 1949. The selection for litter size, based on the average litter size of the litters from which the individual pigs were selected, was for larger litters. There was an increase in the average litter size of litters farrowed by gilts by gilts. However, environmental influences accentuated the changes in litter size greatly during the period of development studied. The amount of selection, based on the birth weight of the individual pigs selected, weighted for the number of times their genetic influence was weighted on the succeeding generation was not positively associated with the birth weight of their offspring. The selection for birth weight based on the average birth weight of the litter from which individual pigs are selected is the best indication of their inherent ability to utilize available environmental conditions as well as their ability to provide an adequate uterine environment for their offspring. There was selection for pigs from litters with average birth weights below that of average of the population from which they were selected. There was a decrease in the average birth weight of the live pigs farrowed. It has been demonstrated that environmental influences are the major cause of variations in the birth weights of new born pigs within the litter. It is therefore possible that the ability of a sow to farrow pigs of greater uniformity at birth is a heritable characteristic. Using the within litter standard deviation of birth weights of live pigs farrowed for each litter as an index to the uniformity of the birth weights of the litters from which the parents were selected and the uniformity of the birth weights of their litters. It was concluded that the characteristic is heritable. There was selection and progress made in the development of the line toward more uniform litters at birth.
Book Synopsis Influence of Inbreeding and Other Factors on Litter Size in Chester White Swine by : H. O. Hetzer
Download or read book Influence of Inbreeding and Other Factors on Litter Size in Chester White Swine written by H. O. Hetzer and published by . This book was released on 1940 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pig Health written by John Carr and published by CRC Press. This book was released on 2018-04-17 with total page 1001 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maintaining the health of pigs is vital in pig farming and production. This new book written by experts from around the world focuses on the health of pigs, first with coverage of the disorders of pigs organised by clinical sign and body system. The book explores environmental medicine and then health maintenance. Treatment options are discussed, emphasizing a reduction in antimicrobial use and an increased awareness of a holistic approach to treatment. The book includes over 1,500 high-quality illustrations to enhance the clinical description, as well as a wealth of high-quality videos to test the reader in making differential diagnoses with treatment options. Quizzes at the end of each section also encourage reflective learning. International experts from the UK, USA, Australia, Spain and Taiwan cover clinical examination of the individual pig and groups along with environmental medicine, making this the ideal reference for veterinary practitioners and students. Those interested in population medicine (poultry, aquaculture, cattle and small ruminant and apiaries) will particularly enjoy the holistic approach to veterinary medicine. All those who appreciate the many talents of pigs will enjoy the practical approach to managing the health of their animals. This book moves veterinary science forward, promoting health rather than treating disease. It will be your number one reference for keeping your pigs healthy.
Book Synopsis Factors that Influence Litter Size in Pigs by : L. Kirk Clark
Download or read book Factors that Influence Litter Size in Pigs written by L. Kirk Clark and published by . This book was released on 1985 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Physiological Aspects of Two Candidate Genes for Litter Size in Pigs by : Birgitte Theodorus Theresia Maria Rens
Download or read book Physiological Aspects of Two Candidate Genes for Litter Size in Pigs written by Birgitte Theodorus Theresia Maria Rens and published by . This book was released on 2001 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Genetic and Environmental Factors Influencing Gain and Fatness in Swine by : David Frame Cox
Download or read book Genetic and Environmental Factors Influencing Gain and Fatness in Swine written by David Frame Cox and published by . This book was released on 1959 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Genetic and Other Factors Affecting Pre-weaning Performance of Maryland No. 1 Swine by : Willard Wynn Green
Download or read book Genetic and Other Factors Affecting Pre-weaning Performance of Maryland No. 1 Swine written by Willard Wynn Green and published by . This book was released on 1958 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Some genetic and environmental factors affecting performance and carcass measurements in swine by : DAVID TUPPER SPURR Spurr
Download or read book Some genetic and environmental factors affecting performance and carcass measurements in swine written by DAVID TUPPER SPURR Spurr and published by . This book was released on 1969 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Factors Affecting Litter Size in Swine ... by : Feng Yang
Download or read book Factors Affecting Litter Size in Swine ... written by Feng Yang and published by . This book was released on 1949 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Selection for Increased Litter Size in Swine by : Francisco Feranil Peñalba
Download or read book Selection for Increased Litter Size in Swine written by Francisco Feranil Peñalba and published by . This book was released on 1984 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
