Semen Discarded During Different Stages of Cryopreservation in Ongole (Bos indicus) Bulls Manda Srinivas 1* , Makkena Sreenu 2 , Srilatha CH 3 , Babu Rao K 4 and Naidu KS 4 1 Department of Veterinary Gynaecology & Obstetrics, NTR College of Veterinary Science, Gannavaram, India 2 Department of Veterinary Surgery & Radiology, NTR College of Veterinary Science, Gannavaram, India 3 Department of Veterinary Pathology, College of Veterinary Science, Tirupati, India 4 Livestock Research Station, LAM, Sri Venkateswara Veterinary University, Guntur, India * Corresponding author: Manda Srinivas, Department of Veterinary Gynaecology & Obstetrics, NTR College of Veterinary Science, Gannavaram, India, Tel: +919951332132; E-mail: smanda64@yahoo.co.in Received date: February 15, 2016; Acc date: February 24, 2016; Pub date: February 26, 2016 Copyright: © 2016 Srinivas M, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Indian subcontinent is a treasure house of Bos indicus cattle, one of the most popular breed amongst them is “Ongole” which by inheritance is a dual purpose breed. During the period under report 549 ejaculates were collected from eight breeding bulls, of which 192 ejaculates (34.97%) were discarded during various stages of semen processing. Out of the total ejaculates, 126 (22.95%), 40 (7.29%) and 26 ejaculates (4.74%) were discarded after collection, equilibration and freezing, respectively while most of the discards were second ejaculates. From the present study, it was concluded that the ejaculate discard in Ongole bulls was mainly based on low volume, initial progressive motility, sperm concentration and post-thaw motility. However, it was suggested that certain reproductive technologies like Sephadex or Glass wool filtration or Percoll gradients could be used to enhance the quality of these low grade ejaculates from genetically superior bulls. Keywords: Cryopreservation; Bos indicus; Ongole bulls; Ejaculate discard Introduction Indian subcontinent is a treasure house of Bos indicus cattle, one of the most popular breed amongst them is “Ongole” which by inheritance is a dual purpose breed well known for its thrifiness, hardiness and disease resistance. It has been observed that in indigenous as well as crossbred bulls a huge percentage of ejaculates were discarded due to low motility, high proportion of abnormal sperms and poor freezability during various stages of semen freezing [1,2]. Tere might be species diferences in overall sperm sensitivity to cryopreservation; the ejaculate was heterogeneous with a variable resistance to osmotic stress amongst the cells [3]. Under tropical conditions, exotic breeds showed signifcantly seasonal fuctuations in semen characteristics as high ambient temperature during summer adversely afected the testicular size, libido and semen quality and epididymal spermatozoa by elevated testicular temperature with decreased the ability of spermatozoa to maintain motility and acrosomal integrity afer freezing [4]. In comparison to fresh semen, 8 times more cryopreserved bovine sperms were required to achieve equivalent fertilization rates in vivo [5]. Mechanization of agricultural practices and introduction of cross breeding programme lead to a drastic decline in the population of the pure Ongole bulls. Ultimately, selection of breeding bulls was dependant on phenotypic characters as availability of good pedigreed bulls was limited. Hence, the current situation demands studies on the factors responsible for semen discards and/or methods to utilize the discarded ejaculates by adopting suitable assisted reproductive technologies to exploit the available germplasm to the fullest potential. For efective utilization of superior germplasm it was necessary to minimize the ejaculate discard rate [6]. For breeding bulls used in artifcial insemination, the information on semen characteristics, fertility and semen production efciency are some of the important basic parameters, such information in Ongole bulls is lacking. Perusal of literature revealed paucity of information on indigenous breeding bulls especially Ongole breed pertaining to the number of ejaculate discard rate during various stages of semen freezing. Material and Methods Semen was collected from 8 breeding bulls, once in a week with the standard artifcial vagina using an anoestrus cow as a dummy during the period under report from January 2009 to March 2010. Each time two ejaculates were collected at a gap of 20 to 30 minutes afer allowing one or two false mounts. During the period under report 549 ejaculate were collected. Soon afer the collection, the semen tubes were numbered and kept in a water bath at 37°C and transferred to the laboratory for further evaluation and processing. Te criteria adopted to accept fresh semen for further processing was that it should possess mass activity of atleast ++ and above, initial progressive motility of more than 70% and sperm concentration of not less than 500 million per ml of neat semen. Te samples were diluted with TRIS fructose citric acid egg yolk glycerol (8%) dilutor based on the number of viable sperm and concentration such that a minimum concentration of 30 million sperms per dose of 0.5 ml was available. Te diluted semen was treated at 5°C for 6 h as equilibration period. A sample of diluted semen from each bull was accepted if the pre freeze progressive motility was a minimum of 60%. Te diluted semen was flled in medium sized (0.5 ml) French straws and frozen in liquid nitrogen vapours (rapid horizontal freezing) adopting standard freezing protocol. Te frozen semen straws were thawed at 37°C for 30 sec afer 24 h post freezing and evaluated of post thaw progressive motility Srinivas, et al., J Veterinar Sci Technol 2016, 7:2 DOI: 10.4172/2157-7579.1000310 Research Article Open Access J Veterinar Sci Technol ISSN:2157-7579 JVST, an open access journal Volume 7 • Issue 2 • 1000310 J o u r n a l o f V e t e r i n a r y S c i e n c e & T e c h n o l o g y ISSN: 2157-7579 o J r u n l a o f V e t e r i n a r y S c i e n c e & T e c h n l o g o y ISSN: 2157-7579 Journal of V Journal of Veterinary Science & eterinary Science & Technology echnology