| The development of Chinese buffalo dairy industry is lagging behind at present. As the consumption of high quality dairy product increasing, there is a need to expand the genetic merit of river buffalo, whose milk production is much high than that of swamp buffalo.The utilization of sex control technique can promote the rapid breeding of superior varieties and the expansion of the utilization of buffalo cows, and speed up the rapid industrialization of animal husbandry combined with oriented process in china. In order to increase fertility with artificial insemination (AI) of flow-sorted, sexed sperm of buffalo. The objective of this study was to analysis the factors associated with conception rate (CR), female calf proportion rate and pregnancy loss (PL) in buffaloes. The study was divided into two parts, as follows.Part I Field data consisted of4,540inseminations of buffalo herds were collected over a period of1.5yr (July,2009to December,2010) by artificial insemination technicians in Guangxi, China. It was conducted to evaluate the differences and investigate the relative effects of the age and parity of buffalo cows, technician, season, sire, semen type, some fertility parameters of swamp buffaloes and the crossbred buffaloes of river breed in their fertility when X-sorted semen were involved. Semen of buffalo bulls was sexed by a collaborating company and commercially distributed in0.25ml straws with a total of2million X-sorted spermatozoa, which was produced from two major river breed buffaloes, Murrah and Nili-Ravi bull. The pregnancy detection was performed by rectal palpation60-90days post-insemination.(1) In the current study, the overall mean CR following AI was48.35%(2,195/4,540). Female calves among breeds, and sexed sperm used in AI was X-sorted, accounted for87.39%(1,684/1,927). However, the abortion rate of heifers accounted for5.21%(5/96), which was higher than parous buffaloes (24/1,852;1.30%).(2) Following the parity of buffalo cows, the CRs of heifers and parous buffalo cows were48.73%(96/197) vs.48.53%(1,852/3,816) respectively, there was no statistical difference between them (p>0.05).(3) Following age at breeding, the trial showed that the CRs of2-4years old buffalo cows got similar pregnancy rates to those from5-7years old buffalo cows (370/779,47.50%vs.935/1,853,50.01%, p>0.05), both of which were higher (p<0.05) than those of8years of age or older (592/1,289;45.93%).5-7years old buffalo cows appears the peak of breeding.(4) Comparing some fertility parameters of swamp buffaloes with the crossbred buffaloes of river breed, the CRs of crossbred buffaloes are slightly higher than the swamp type. Conception rates were non-significantly different between animals inseminated with swamp type, crossbred F1and crossbred F2:52.57%(143/272),60.29%(41/68) and49.13%(1,984/4,038), respectively (p>0.05).(5) Following cervical insemination in Wuming County, the overall mean CRs of8technicians following AI was42.94%(651/1,516). Buffalo cows inseminated by No.15had got the highest CR (72/113,63.72%), No.14had got the lowest CR, and the highest is6.05times than the lowest. Marked significant difference was observed (p<0.05) among the technicians proven skills for sexed control techniques in CRs to be most important.(6) The CR of sexed sperm derived from Nili-Ravi bull was46.15%(1,299/2,815), significantly lower than that of52.46%(895/1,706) from Murrah bull (p<0.05).(7) In this study inseminations of sexed sperm were carried out throughout the whole year. Seasons were defined in the following way:spring (March to May), summer (June to August), autumn (September to November), and winter December to February). There was no significant difference (p>0.05) between summer and autumn (408/776,52.58%vs.602/1,165,51.67%). Lower CRs were observed in winter (552/1172,47.10%). There were significant differences when compared the CR in spring with winter (337/794,42.44%vs.552/1,172,47.10%).Therefore, we concluded that AI with sexed-sorted semen in summer or autumn which was an effective means of increasing CRs in buffalo cows. In terms of economic efficiency, the selection of bulls and crossbred buffalo cows for sperm sexing would be of great importance to increase fertility.Part II The present study on the use of sexed semen (2×106) for artificial insemination was carried out and compared with artificial insemination using nonsexed semen (2×106) and conventional semen (2×107) form July to November,2012. It was conducted to outline possible relationships among some important variables, namely sperm dosage, age at breeding of herds, sire on the establishment and maintenance of pregnancy per AI (P/AI) in buffaloes. Sexed semen was primarily used at first service. Pregnancy was determined60to90d after (1) The results revealed that CRs of each semen type by sperm dosage combination were as follows:2×106sex-sorted,48.15%, n=324;2×106unsex-sorted,51.94%, n=156; and2×107conventional,58.18%, n=220. There was no significant difference between buffalo cows inseminated with2×106sexed senmen and2×106nonsexed semen (P>0.05); There were statistical difference (p<0.05) when the sexed semen compared with conventional semen (P<0.05). Among parous buffalo cows, CRs of2×106nonsexed semen (148/315,46.98%) were substantially higher than with sexed semen51%(102/200).(2) Following age at breeding, to2-4years old,3-5years old buffalo cows, the CRs of sexed semen got similar pregnancy rates (p>0.05) to those from2×106nonsexed sperm (46.15%vs.55%;53.57%vs.46.51%). To8years of age or older buffalo cows, the two were significant (43.84%vs.63.75%).(3) For the production of sexed and nonsexed semen of two sires, the CRs with artificial insemination showed significant differences. Therefore, to select the high quality sire in the process of producing sexed semen which implies that the ranking of the bulls changes with the number of spermatozoa inseminated. |
PDF Full Text Request