Differences Of Courtship And Mating Behaviors And Their Effects On Fertilization Rate Between Different Geese Breeds

The economic hybridization between different geese breeds has become one of the main means of the current geese production.We previously found that the hybridization of different geese breeds showed higher heterosis,but its fertilization rate was significantly lower than purebred production.It has not been reported yet whether there is a mating disorder(selective mating and competitive mating)between different breeds,which causes a decrease in fertilization rate.According to the study above,the methods of observing and recording was used in our study.We took Zhedong white geese,Sichuan white geese and Carlos geese as the research objects and formed multi-male parent families which consist of Zhedong white geese ?× Sichuan white geese?(ZC),Sichuan white geese ?× Zhedong white geese ?(CZ),Zhedong white geese ?× Zhedong white geese ?(ZZ),Sichuan white geese ?× Sichuan white geese ?(CC),Carlos geese ?×Sichuan white geese ?(KC),Sichuan white geese ?× Carlos geese ?(CK),Carlos geese ?×Carlos geese ?(KK),Sichuan white geese ?× Sichuan white geese ?(CC).By adapting video automatic acquisition system to observe and compare the mating behavior among different combinations,it could reveal the differences of courtship and mating behaviors and the effects on the fertilization rate.The study provided a certain theoretical basis for scientific selection,improving management system,developing waterfowl productivity and economic benefits.The main findings are as follows:Firstly,to reveal the differences of courtship and mating behavior between different geese breeds,by observation,geese courtship,including initiative courtship of gander,initiative courtship of goose and gander-goose mutual courtship.Initiative courtship of ganders was the main type of geese courtship.There were special behaviors such as continuous mating,fixed mating,competition disturbance,goose crawling and so on in Zhedong white geese and Sichuan white geese;Carlos gander owned one-to-one mating,grade sequence and competition interference so that we advised that the gander should be eliminated in the conservation process of Carlos geese to maintain the genetic diversity of the population.We also observed obvious mating selectivity in both male and female of the Zhedong white geese.There was obvious mating selectivity,poor affinity and low degrees of adaptability in geese between Carlos geese and Sichuan white geese.Crossbreeding Zhedong white geese with Sichuan white geese,on the whole,the frequency of gander initiative courtship in the pure breeding group was higher than that of hybrid group,however,the time of courtship was longer,among which,Sichuan white geese,which was in the pure breeding group(16.00 times/day,14.15s),showed significant difference when compared with,Sichuan white geese ?× Zhedong white geese ? group(11.93times/day,17.34s)(P<0.05).Namely,a decline in courtship frequency could result from crossbreeding different breeds.The frequency of Zhedong white geese courting and chasing ganders was higher than that of Sichuan white geese,while Sichuan white geese ?× Zhedong white geese ? group was higher than others(P<0.05),that is to say.Zhedong white female geese have stronger ability of courtship than that of Sichuan white geese.Crossbreeding different breeds would lower the frequency of goose cooperated mating,thereinto,there were significant differences between the pure breeding group of Sichuan white geese(20.43 times/day)and the Sichuan white geese ?× Zhedong white geese? group(15.71 times/day)(P<0.05).We judged that the best affiliation time of every group was 11 to 15 days according to frequency of courtship and mating behavior,which provided certain basis on that we could determine the time to collect eggs for different crossbreeds.Crossbreeding Carlos geese with Sichuan white geese,on the whole,crossbreeding of different breeds affected significantly the courtship and mating behavior.The frequencies of gander's courting,mounting,coupling,mating successfully and goose's cooperated mating in the crossbreeding group were lower than that of the pure breeding group,especially the frequency of all the behavior above in the Sichuan white geese pure breeding group was significantly higher than others(P<0.05),which means that Sichuan white geese showed stronger ability of courting and mating when compared with Carlos geese.The results suggested that the ratio of male to female should be adjusted in order to ensure the reasonable number of gander's mating and courting in the future utilization of crossbreeding different breeds(Chinese geese and European geese).Secondly,to reveal the level of the serum sex hormone of ganders and geese with different intensities of mating,the results showed that the testosterone level of ganders who mated successfully more than 40 times(111.42 ng/L)was significantly higher than that of ganders mating less than 30 times(81.48 ng/L)(P<0.05).The estradiol level of goose which courted and mounted frequently(47.52 ng/L.57.65ng/L)was significantly higher than that of goose refusing to mate(13.57ng/L)(P<0.05).The results suggested that serum sex hormones affected courtship behavior to some extent.Thirdly,to elucidate the relationship between mating behavior and the egg fertilization rate,statistical analysis showed that in different combinations of Zhedong white geese and Sichuan white geese,egg fertilization rate and successful mating times were significantly positive correlated(rp = 0.992*,P<0.05),and the egg fertilization rate was not related with three kinds of courtship behavior.In different combinations of Carlos geese and Sichuan white geese,the fertilization rate was positively correlated(rp = 0.975*,P<0.05;rp = 0.980*,P<0.05)with ganders' successful mating times and the total mating behaviors,and was not related with the number of three kinds of courtship behavior.The results revealed that in the production the fertilization rate could be improved by increasing the number of successful mating.This study revealed the differences of courtship and mating behaviors between geese combinations include Zhedong white geese,Sichuan white geese and the Carlos geese,and found that egg fertilization was significantly related to the successful mating(gander).That is,in the range of the certain mating times,the fertilization rate increased with larger numbers of successful mating.