家禽育种方法,家禽的选择 家禽的配种 家禽品系培育 现代家禽繁育体系,家禽的选择,根据外貌与生理特征进行选择 使用范围:种禽繁殖场 肉用系:于5-7周龄进行选择; 标准:生长迅速,体重大,羽毛丰满,无生理缺陷。 蛋用系:于6-8周龄进行选择; 标准:羽毛生长迅速,体重符合要求(不过大也不过小),无生理缺陷。 种用育成禽：于20-22周龄进行选择; 标准:体型结构、外貌特征符合品种要求，身体健康，生长发育健全。,家禽的选择,根据记录成绩进行选择 性能记录 蛋鸡：产蛋量，蛋重，产蛋重，蛋壳品质(蛋壳厚度和强度、蛋形、哈夫单位、蛋壳颜色、蛋壳组织、血斑与肉斑)，性成熟期，产蛋率，体重，耗料、抗病力，雏鸡成活力，产蛋期成活力，受精率，孵化率等； 肉鸡：上市体重，羽毛生长速度，绒羽颜色，屠宰率，屠体品质，耗料，性成熟期，成年体重，蛋重，蛋壳品质，入孵蛋%，死亡率，受精率，孵化率。 上述项目可根据实际情况选择记载。,家禽的选择性能测定,根据系谱资料进行选择（系谱测定） 对于雏禽和育成禽，因不能断定成年后其生产性能如何，另外公禽本身不能产蛋，此时可查它们的系谱，比较不同公鸡祖先的生产性能记录以推断它们可能继承其祖先的什么性能。 运用系谱测定时，血缘越近影响越大，因此一般着重比较亲代和祖代即可。 根据本身成绩进行选择（个体测定） 与系谱测定比较,个体测定能更准确的反映个体的性能; 依据个体测定进行选择只适于遗传力较高的性状。,家禽的选择性能测定,根据全同胞和半同胞性能进行选择（同胞测定） 由于公禽不能产蛋，因此一般使用其全同胞和半同胞姐妹的性能对其蛋用性状进行选择； 屠宰性状或屠体品质性状一般也通过同胞测定进行选择。 根据后裔成绩进行选择（后裔测定） 后裔测定是根据记录进行选择时准确性最高的方法； 通过后裔测定的公禽一般年龄较大（至少二岁半以上），利用时间已不多，但可通过后裔测定建立优良家系。,Progeny test,The term progeny test as applied to animal breeding refers to the estimation of an individuals value as a breeder by means of the qualities or performance of its offspring. The application of the progeny test to breeding operations has brought one important fact to the attention of the poultry breeder. This is that it is not only necessary to consider the results of single pair matings but also to consider all of the offspring of a mating.,Application of progeny test to production breeding,It is doubtless true that much of the rapid progress in improvement of egg production during recent years has been due to the appreciation of the value of the progeny test as a tool by most of the leading breeders. This method not only makes it possible to predict with greater accuracy the performance of individuals but also to estimate their value as breeders, thus permitting more rapid improvement of the flock. For purposes of elimination it is very important that the poultryman have the record of a poor-producing family as well as that of good producers.,Application of progeny test to production breeding,If the purpose is to progeny test a group of cockerels the usual procedure is to organize several breeding pens carrying females of approximately equal egg records. This may be accomplished by using untested females that have just completed their first year of production. It will make possible the testing of the females as well as the males. Each pen is headed by one of the males to be tested.,Application of progeny test to production breeding,The average production of the daughters is used as a basis for comparison of the ability of the males to transmit egg production tendencies. By the same method it is possible to compare the females within a single pen, and since all of their daughters receive the genetic determiners for egg production on the paternal side from a single male.,Prepotency index,If the males to be compared have not been mated to females of similar egg records some compensation must be made for the variability in the dams records. An index value which might be called the “prepotency index” may be utilized in poultry breeding. Instead of using the average production of the daughters as a basis for comparing the transmitting abilities of males, the average records of both their daughters and mates are considered.,Prepotency index,The first step in calculating a males prepotency index is to compute the average production of the daughters of each female mated with him. The resulting average may be considered a measure of the combined transmitting tendencies of the pair of birds involved. The dams inherited tendencies for egg production are indicated by her individual egg record, but the males tendencies are unknown.,Prepotency index,The difference between the record of a female and those of her daughters should supply some clue as to her mates ability to transmit egg-production tendencies. A males breeding value is estimated as follows: A males prepotency index is then the average of the estimations obtained from the groups of daughters of his various mates.,Prepotency index,By use of the index i t is possible to compare males mated to females of varying production, but it should be realized that the attempted corrections are sources of considerable error. It is much better, wherever possible, to compare only males whose mates are as nearly comparable as possible.,Prepotency index,Difficulty in application of progeny test,One of the most serious handicaps in the application of the progeny test to production breeding is the long period of time required to make the test. If a male is used as soon as he reaches sexual maturity, or at approximately one year of age, he will be starting his fourth year before the test is completed on his first group of daughters. Many breeders use supposedly valuable males repeatedly while the progeny test is being obtained and then discard unsuccessful blood lines and concentrate on the proved ones. This procedure involves rather extensive facilities and much lost motion.,A SHORT-CUT PROGENY TEST,Any method which will provide a reasonably accurate progeny test and