Open Access 
              
Copyright: The authors. This article is an open access 
article licensed under the terms of the Creative Commons Attribution License 
(http://creativecommons.org/licenses/by/2.0) which permits unrestricted use, 
distribution and reproduction in any medium, provided the work is properly 
cited.
              
              
                            
                            
                            Original Research
                            
                            
                            1. 
                            
                            Estrus induction and fertility response in delayed 
                            pubertal Kankrej heifers treated with norgestomet 
                            ear implant -
                            
                            
                            C. F. Chaudhari, B. N. Suthar, V. K. Sharma , V. 
                            S. Dabas , N. F. Chaudhari , H. H. Panchasara
                            Vet World. 2012; 5(8): 453-458
              
               
              
              doi: 
              10.5455/vetworld.2012.
453-458
              
              
               
              
              
              
   
 
              
               
               
               
              
              
              Abstract
              
              
                            Aim: 
                            The study was undertaken to find out the estrus 
                            induction and fertility response in delayed pubertal 
                            Kankrej heifers treated with norgestomet ear 
                            implant. 
              
                             Materials and Methods: Total 
                            eighteen anoestrus Kankrej heifers of delayed 
                            puberty weighed above 250 kg and attained between 30 
                            to 36 months of age were selected and divided in to 
                            three groups of six animals each at random to 
                            conduct the experiment. Animals in group 1 were 
                            implanted Crestar ear implant for 9 days. In 
                            addition to this, group 2 received 500 IU of PMSG on 
                            the day of implant removal. In group 3, treatment 
                            protocol remained same as in group 2, but Inj. 
                            Receptal @ 2 ml was given additionally at the time 
                            of breeding. Results: All the animals 
                            exhibited estrus with average duration of 25.41+ 
                            0.94, 21.95+ 0.20 and 22.68 + 1.46 hours between 
                            implant withdrawal and estrus induction in group 1, 
                            2 and 3, respectively. The duration of estrus was 
                            significantly (P<0.05) longer (25.61+ 2.95 hours) in 
                            group 2, followed by group 1 (18.88 + 1.45 hours) 
                            and group 3 (13.48 + 1.92 hours). The pregnancy rate 
                            at induced estrus was 33.33 percent in group 2. In 
                            group 1 and group 3 none of the heifers found 
                            pregnant at induced estrus. The overall conception 
                            rate was maximum in group 2 (66.67 percent) followed 
                            by group 3 (50 percent) and group 1 (33.33 percent) 
                            after the 3rd service. 
              
                             Conclusion: Although 
                            the conception rate at induced estrus was lower, 
                            norgestomet ear implant could be utilized to induced 
                            estrus in delayed pubertal cow heifers. 
              
                             Keywords:
                            Conception rate, Delayed puberty, Estrus 
                            induction, Heifers, Norgestomet