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Showing 1 to 20 of 86 for “"litter size"”.
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Variance Components of litter size in Icelandic farmed mink (Neovison vison)
An analysis of variance components and a study of pedigree structure was carried out using Icelandic field data. Data from six farms was included, total of 88°928 animals in the pedigree. Two methods were employed, MCMC Gibbs sampler method and REML. The two different methods gave similar results. …
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The Influence of Uterine Growth on The Potential Litter Size in Chinese and Occidental Pigs
Litter size at birth is determined by the number of ovulations, proportion of eggs fertilized and the proportion of embryos and fetuses surviving. Differences in litter size amongst breeds are directly related to the length of the pregnant uterus. Each fetus regardless of breed requires a similar …
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Estimation of genetic parameters for development of alternative selection criteria for increased litter size in Rambouillet sheep
… heritabilities of and genetic correlations among litter size, ovulation rate, scrotal circumference and body weight in Rambouillet sheep were estimated using REML (Restricted Maximum Likelihood) via an EM (Expectation-Maximization) type algorithm. Data were obtained from the University of Illinois …
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A Study of Effects of Blood Types, Sires, Litter Size and Other Factors on Sex Ratios in Pigs
… as by the least-squares method. Effects of sire, litter size and selection for high whole-body potassium per unit weight of boars on sex ratios were all considered. A total of 1,328 litters of pigs over seven generations in five breed classes (Duroc, Duroc selected, Yorkshire, Yorkshire selected …
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A Comparison of Intrauterine and Cervical Artificial Insemination Rods on Farrowing Rate and Litter Size in Artificially Mated Sows
… on farrowing rate and number of piglets born per litter. Three hundred eighty-nine sows were allotted into two experimental groups based on parity, body condition, and breed of sire influence of the sows. One hundred ninety-three matings were performed using the experimental intrauterine rod, and …
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Selection to improve spring fertility in a crossbred sheep population
… Traits considered were spring fertility, faIl litter size, live weights at birth, weaning, and at about 90 and 120 d of age, and scrotal circumference at weaning and at about 90 and 120 d of age. Fertility was defined as 1 or 0 depending upon whether a ewe lambed or failed to lamb, …
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Genetic Analysis of Sheep Discrete Reproductive Traits Using Simulation and Field Data
… scale to the normal scale for fertility and litter size performed better for a simple animal model than for a repeatability model. Genetic correlation estimates between the two categorical traits for Model 1B and 2B were .49 ± .01 and .48 ± .04, respectively, and were close to the expected …
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Heat Stress Induced Fetal Dwarfing and Uterine Blood Flow in Sheep
… dwarfing. Birthweight adjusted for sex and litter size was reduced 1.8 kg in trial 1 (P < .05) and 1.9 kg in trials 1 and 2 combined (P < .06) with maternal heat stress. Lamb sex, litter size, lamb condition and gestation length were all correlated (P < .05). Restriction of feed to 70 …
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Association of Polymorphic Blood Group Systems and Relative Fitness in Pigs
… analyses and least squares analyses of litter size and perinatal and preweaning survivabilities were used to study possible mechanisms of natural selection with respect to polymorphic blood group systems. In the G and H systems, parental incompatibility appeared to be the major cause for …
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A study of factors affecting preweaning traits in inbred and linecross swine
… the differences between inbred and linecross litters in litter size and litter weight at birth, 21 and 56 days of age. The effect of line of dam, age of dam and year of birth on each of the production traits was also studied. Data comprising 556 litters (229 inbred and 327 linecross) from …
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Management and nutrition of the replacement gilt.
… of gilt management strategies as well as litter size at first farrowing; however, incidences of reproductive failures and small first litter sizes are common within cohorts of replacement gilts. Hence, this thesis had two primary aims which were addressed in four experiments; one, to …
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Platyrrhine Phylogenetics With A Focus On Callitrichine Life History Adaptations
… was investigated. The timing and mechanism of litter size reduction in Goeldi's monkey was accessed though detection of chimerism and adaptive evolution of genes involved in reproduction. We determined based on these analysis that the reduction in litter size is likely pre-ovulation and due to …
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The influence of weaning age on growth and development of the baby pig and reproductive efficiency in the sow
Thirty-nine litters containing 385 pigs of mixed breeding were weaned at 1, 7, 14, 21, 28 or 35 days of age in two experiments conducted during the spring and summer of 1966 . A creep ration constituted the only diet from weaning to 56 days with the exception of pigs weaned at 1 or 7 days. These …
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Manejo em cativeiro e biologia reprodutiva de duas espécies de Thrichomys (Rodentia: Echimyidae) provenientes do Piauí e do Mato Grosso do Sul
… in growth rate and several reproductive traits (litter size, body mass at birth and weaning, sexual maturation). T apereoides laurentius, living in harsh environment has a higher reproductive potential. It has larger litter size, smalIer body mass of infants and higher growth rate than T …
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Investigations of the action of vitamin A and beta carotene on reproductive performance in pigs
… timing of treatment with retinol to increase litter size in the sow.
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Factors affecting fertility in frozen-thawed boar sperm
… by reduction in fertility measures such as litter size. The reduced fertility results from the damage sustained by the sperm cell during cryopreservation. However, increased understanding of this damage has lead to improved cryopreservation methods, ultimately increasing post-thaw viability …
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Methods to reduce rectal temperature decline of newborn piglets and the effect of cross-fostering strategies on piglet pre-weaning growth and mortality
… have been significant increases in the average litter sizes of commercial sows over recent decades. As a result, average piglet birth weight has decreased, and the number of low birth weight piglets (i.e., < 1 kg) has increased. Lower birth weight piglets have higher levels of mortality, …
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ΤΡΟΠΟΠΟΙΗΣΗ ΤΟΥ ΑΝΟΣΟΠΟΙΗΤΙΚΟΥ ΣΥΣΤΗΜΑΤΟΣ ΤΗΣ ΑΙΓΑΣ ΓΙΑ ΑΥΞΗΣΗ ΤΟΥ ΡΥΘΜΟΥ ΑΝΑΠΑΡΑΓΩΓΗΣ
… DAIRY GOATS INCREASES OVULATION RATE AND LITTER SIZE.- THE INCREASE NUMBER OF OVULATED FOLLICLES IS RATHER THE RESULT OF A DECREASEIN PLASMA UNCONJUGATED PROGESTERONE LEVEL, WHILE THE TOTAL PLASMA PROGESTERONELEVEL WAS HIGHER IN IMMUNIZED THAN IN CONTROL GOATS. IT SEEMS THAT PROBABLY THE …
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Effects of adverse prenatal environments on the physiology and behaviour of the offspring
… age, and these alterations differed by sex and litter size. In response to isolation, maternal PCUN reduced attempts to escape in offspring at 4 months and suppressed plasma cortisol AUC at 18 months of age. Maternal PCUN did not affect offspring behavioural reaction in response to a human. The …
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