Lamberson, W. R.Ramos, Alcides Amorim [UNESP]Malhado, C. H. M.Jorge, Andre Mendes [UNESP]Ferraz Filho, P. B.DeFreitas, J. A.De Souza, J. C.2014-02-262014-05-202014-02-262014-05-202007-01-01Italian Journal of Animal Science. Pavia: Pagepress Publ, v. 6, p. 593-596, 2007.1594-4077http://hdl.handle.net/11449/14146Reproductive rate is an important component of economic success in livestock production. Parturition interval (IEP) is a direct measure of the productivity of the animal. Long IEP reduce the number of calves produced per year. The objective this study was to determine the distribution of parturitions across month and to evaluate factors affecting IEP. The data included 7,588 parturitions of Murrah, Mediterranean and Carabobo buffalo from 10 herds in Southern and South-eastern Brazil. The analysis of distribution of parturitions evaluated the effects of month, year and their interaction on birth date of calves by using a Chi-Square test in SAS PROC FREQ (SAS Institute, Cary, NC, USA). Parturition intervals (n = 2,630) were evaluated using analysis of variance in SAS PROC GLM. The model for IEP included the fixed effects of season (December to May = 1, June to November = 2), year, season x year, sex of the preceding parturition, age of weaning of the previous calf, and herd. All sources of variation were significant (P<0.0001) except sex of the preceding parturition (P <0.85). The mean IEP was 446.7 +/- 10.4 days, for seasons 1 and 2 IEP were 419.8 +/- 11.3 and 473.6 +/- 40.7 days, respectively, a difference of 54 days. As weaning age increased there was a lengthening of IEP. Buffalo in Brazil showed seasonal parturition with calving concentrated from January to April, although the frequency by month differed across years (P<0.0001). These months also had the lowest calving interval.593-596engCalving intervalReproductionSeasonArtigo10.4081%2Fijas.2007.s2.593WOS:000207598400118Acesso abertoWOS000207598400118.pdf8878595413452908