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Improving management for higher reproduction accelerates genetic improvement in closed herd of swine
Masahiro SATOH 《Animal Science Journal》2004,75(6):499-502
The present study compared responses to selection at different conception rates and litter sizes at weaning in a simulated closed herd in a swine breeding program. The base population consisted of 10 males and 50 females, and 10 generations of selection was practiced by using individual phenotype or best linear unbiased prediction of breeding values for a trait with heritability (h2) of either 0.2 or 0.5. The probability of conception in a single mating was assumed to be 0.8, 0.9 or 1.0. Litter size at weaning was sampled randomly from a normal distribution with mean 8, 10 or 12 and variance 8.1225. Genetic response increased by approximately 6% for h2 = 0.2 and approximately 5% for h2 = 0.5 at generation 10 when conception rate was increased from 0.8 to 1.0. However, litter size at weaning did not affect response to selection. In conclusion, improving conception rate by environmental management increases genetic response indirectly in a breeding program of a closed swine herd. 相似文献
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Kumiko TAKEDA Masahiro SATOH Shreeram P. NEOPANE Bahadur S. KUWAR Hari D. JOSHI Nanda P. SHRESTHA Hiroshi FUJISE Mariko TASAI Takahiro TAGAMI Hirofumi HANADA 《Animal Science Journal》2004,75(2):103-110
Dwarf Lulu cattle, the only Bos Taurus type of cattle in Nepal, are raised under severe environments in the mountainous zone of that country. In the present study, the body measurement traits, cytogenetic and molecular genetic characteristics of the Lulu cattle are investigated. Blood samples were collected from 31 animals in four villages (altitudes 2590–3550 m) in the southern part of Mustang. The Lulu cattle had a normal karyotype with 2n = 60, XY or XX. Only one male examined had a large submetacentric X‐chromosome and a small submetacentric taurine type Y‐chromosome. The mitochodrial DNA (mtDNA) genotypes were analyzed by PCR mediated restriction fragment length polymorphisms, displacement (D)‐loop region PCR mediated single strand conformation polymorphisms, and D‐loop region sequences. Many base substitutions were found in the D‐loop region, suggesting that the Lulu cattle originated from at least 10 maternal lines. Three types of mtDNA from these cattle were found, the Bos taurus type (n = 23), the Bos indicus type (n = 6), and the Bos grunniens type (n = 2). In the village at the lowest altitude, four of the five cows were of the Bos indicus type. These results indicated that mtDNA types of the Lulu cattle mostly belong to Bos taurus, but have been hybridized with Bos indicus cattle in lower‐elevation regions in their maternal lineage. 相似文献
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Masahiro SATOH 《Animal Science Journal》2006,77(6):566-573
Responses to selection for number of piglets born alive (NBA) by the total number of piglets born (TNB), the NBA, and the NBA plus number of piglets born dead (NBD) were compared using the accuracy of selection and expected genetic gain calculated from the selection index with family information and the real response to selection, using data generated by Monte Carlo computer simulation. The accuracy of selection for NBA selected by TNB was higher than that by NBA only if the genetic correlation between TNB and NBA was close to 1.0, or the value of heritability for the TNB was much larger than that for the NBA. The accuracy of selection for the NBA selected by the combination of the TNB and the NBA was generally highest in the three selection methods in each family structure. Selection by the TNB resulted in the greatest expected genetic gain for the TNB among the selection methods. In the best linear unbiased prediction (BLUP) selection, the genetic gain for the NBA accumulated by the NBA tended to be similar to that accumulated by the combination of the NBA and the NBD, and both genetic gains at generation 10 were significantly larger than that by the TNB (P < 0.001). The accumulated responses selected by the two‐trait animal model BLUP estimated from genetic parameters with errors were similar to those estimated from the true parameters, and there was no significant difference between them. These results indicate that selection by the NBA or by the NBA and the NBD gives more genetic improvement in the NBA than that by the TNB. 相似文献
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Masahiro SATOH 《Animal Science Journal》2004,75(2):97-102
The present study evaluated the advantage of mixed‐model techniques over a selection index under different magnitudes of an additional systematic environmental effect (ASEE) in terms of accuracy of prediction and expected genetic gain. The data attempted to simulate a closed herd in a pig breeding program. The base population (G0) consisted of 10 males and 50 females. Six generations (G0 to G5) were selected by using a selection index of three traits without overlapping. Additional systematic environmental constants with four levels in a generation were assigned from a uniform distribution at different ranges. Breeding values of animals in the last generation (G5) were estimated on the basis of an index of individual phenotype (SI‐U), SI‐U adjusted for ASEE using a least‐squares mean (SI‐A), best linear unbiased prediction using an animal model excluding ASEE (AM‐E), and an animal model including ASEE (AM‐I). Accuracy of prediction and expected genetic gain were larger by the animal model than by the selection index, even if heritability of the traits selected was high and ASEE was set to zero. When ASEE was zero, the accuracy of prediction and expected genetic gain given by SI‐U and AM‐I were similar to those given by SI‐A and AM‐E, respectively. However, the differences in accuracy and expected gain between SI‐U and AI‐A and between AM‐I and AM‐E increased as the range of ASEE increased. It was concluded that selection based on an animal model was more effective than index selection, even if the herd environment was uniform and traits with high heritability were selected, and that it should be always included in an evaluation model, however slight any systematic environmental effect may be in a closed herd. 相似文献
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Mariko TAKAYASU Kouko HAMAMOTO Hiroshi SATOH Toshihiro ICHIJO Toru TAKAHASHI Kazuhisa FURUHAMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(2):261-263
To clarify the effect of renal dysfunction on pharmacokinetics of the prokinetic agent metoclopramide (MCP), we administered intravenously 0.4 mg/kg MCP to healthy calves and calves subjected to right kidney vessel ligation (ligation) without or with a subsequent left nephrectomy (ligation plus removal). Plasma MCP concentration, glomerular filtration rate (GFR) and plasma prolactin level were measured by liquid chromatography-tandem mass spectrometry, simplified equation using iodixanol and enzyme-linked immunosorbent assay, respectively. Only in calves with ligation plus removal, plasma MCP concentrations were increased significantly 6, 8 and 12 hr after injection, showing that a negative correlation was observed between the plasma MCP concentrations and GFR value. A tendency to increase in plasma PRL concentration was noted also in these calves. In conclusions, plasma MCP concentrations depend on the GFR mode in calves, and its critical GFR value was estimated. 相似文献
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ABSTRACT: The present study, one in a series to clarify the phosphorus (P) and nitrogen (N) loading from carp culture, evaluated four commercial diets. The total and available P in these diets varied from 1.57 to 1.86% and from 0.38 to 0.87%, respectively. The control diet, selected based on an earlier experiment, contained 1.40% total P and 0.68% available P. The 7-week feeding trial was performed with juvenile carp. Superior feed gain ratio was obtained for the control diet (1.00) and it varied from 1.19 to 1.56 among the commercial diet groups. Similarly, the control diet showed higher rates of P absorption (43.8%) and retention (33.1%) than the rest (absorption: 18.1–40.9%; retention: 10.7–18.7%). Total P loading (kg/t production) was 10.0 for the control group but ranged from 19.1 to 25.0 among the commercial diet groups. Nitrogen absorption was not markedly different; however, fluctuations in retention resulted in N loading (kg/t production) that ranged between 47.1 and 66.3 among the commercial diets, higher than the 34.8 obtained for the control diet. The available P in the commercial diets rarely matched the requirement level, thereby negatively affecting the waste loading. The superior performance of the control diet underscores the fact that effective formulations help in keeping emission levels low. 相似文献
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ABSTRACT: This study was conducted to gather data on the reduction of environmental phosphorus (P) loading through the formulation of carp diets with different combinations of protein ingredients. Five experimental diets were formulated by substituting fishmeal (FM; 10–20%) with alternative protein sources such as meat meal (MM; 5–15%), blood meal (BM; 5–7%), and defatted soybean meal (dSBM; 6–10%). The control diet used was a commercial carp diet selected based on earlier experiments. Each diet was fed to duplicate groups of juvenile carp three times a day, until satiation for 12 weeks. Feed performance was proportional to the increase in dietary FM levels. Phosphorus absorption ranged between 41.6% and 52.0% among the experimental groups and was 42.6% for the control group, but there were no marked differences in nitrogen (N) absorption rates. Phosphorus retention ranged from 31.4% to 35.7% for the test diets, whereas N retention increased proportionally with dietary FM levels and ranged from 34.7% to 41.7%. The P and N retention values of the control diet were 27.6% and 41.2%, respectively. The total P loading (T-P) increased at the higher FM levels (9.1–10.7 kg/t production), whereas lower FM levels produced higher total N loading (T-N, 34.6–43.1 kg/t production), the figures for the control being 13.9 T-P kg/t production and 35.6 T-N kg/t production. These results indicate that the reduction of FM levels to 10–20% by replacing it with MM, BM, and dSBM in carp diets was effective in reducing the loading of P and N. 相似文献