Growth and Development Analysis of Kongshan Cattle

[Objectives]In order to better understand the performance of Kongshan cattle,their growth and development was analyzed.[Methods]The body weights of 106 kongshan cattle at different month ages were measured,and the growth curves and body measurement indices of Kongshan cattle after one year old were analyzed by SPPS18.0.[Results]Kongshan cattle have good body shape.Compared with 1985,the performance of body measurements and weight was improved significantly;and the body measurements and body weight of Kongshan cattle increased significantly after 24 months old,indicating that Kongshan cattle still have good fattening performance in adulthood.[Conclusions]This study analyzed the growth and development laws of Kongshan cattle and the status quo of the population,and will provide some help for the selection and utilization of Kongshan cattle breed more intuitively.

Investigation on the Growth and Development of Muscle Fibers in Black Goat Lambs

[Objectives]This study was conducted to analyze and study the growth and development of muscle fibers at different stages,so as to provide a theoretical basis for subsequent research on developmental biology and nutritional regulation.[Methods]The body weights of black goat lambs in groups at different month age(0-6 months old)were recorded,and the diameter,area and number of muscle fibers were measured by tissue section and hematoxylin-eosin staining.The curves of body weight and muscle fiber growth and development of black goat lambs were drawn.[Results]The black goat lambs maintained a high absolute growth intensity of 2.95-4.35 kg/30 d throughout the rearing cycle,and the body weight continued to increase significantly,while the relative growth coefficient decreased from 93.05%at the age of 30 d to 13.83%at the age of 180 d.The diameter and area of muscle fibers in black goat lambs showed obvious"three-stage"growth and development characteristics,and showed different trends of gender advantages in different stages.[Conclusions]This study will help to further optimize the key supporting technologies for production and promote the diversified and comprehensive development of the mutton sheep industry in Sichuan Province.

Application Advances of Superdosing Phytase in Pig Production

Phytase is a highly efficient hydrolytic enzyme to release phosphorus in plants,and is widely used in animal husbandry production.It has been proved that low dose phytase has beneficial effects and wide application prospects in animal production and environmental protection.Howev-er,literatures show that superdosing phytase has great promotion effects on the growth potential of pigs,while the research and application of super-dosing phytase are still lacking.This paper summarizes action mechanisms of phytic acid and phytase in recent 20 years,application of superdosing phytase in pig production and other problems in the application process.

Expression Pattern of IGF-I Gene and Correlation between Its SNPs and Growth Traits in Sheep

This study was to investigate the expression pattern of IGF-I gene and correlation between its SNPs and growth traits in sheep.The expression patterns of IGF-I gene in brain,muscle,skin,liver and heart of Liangshan semi-wool sheep were detected at six growth stages（15,60,105,195,240 days） by employing qRT-PCR approach,and the correlation between SNPs of IGF-I gene and growth traits via SSCP method.The first inflection point of IGF-I gene expression was observed at day 105 in all five tissues.From 15-105 days IGF-I gene gave a decline-ascending trend in muscle,brain and liver,while it did not vary significantly during day 15-day 60 and was up-regulated in heart and liver at day 105.Whenafter,the expression level was down-regulated in liver,while that in muscle,heart,brain and skin assumed the second inflection point.The expression levels of IGF-I gene in brain and skin at day 195 were significantly higher than that at day 150 and day 240.These suggest the synchronous expression of IGF-I gene in all five tissues.Two SNPs located at the leader region and exon 3 of IGF-I gene were middle or low polymorphic.The SNP locus detected with primer P-1 was significantly correlated with birth weight of Liangshan semi-wool sheep（P 〈0.05）,while that detected with primer P-2 was significantly correlated with weaning weight and the weaning daily gain（P 〈 0.05）.The expression of IGF-I in all tissues had the similar developmental patterns,and strong correlation of the SNPs of IGF-I gene was confirmed with the eary growth traits to provide theoretical basis for the growth regulation and applying to assisted selective breeding with the SNPs in liangshan semi-wool sheep.