José Candelario Segura Correa

Risk Factors Associated with the Occurrence of the Second-Litter Syndrome in Sows in Southeastern Mexico

The objective was to estimate the incidence of and to determine the effect of some risk factors on the decrease of litter size at parity 2 of sows in three commercial farms in Yucatan, Mexico. Data on 8,592 farrowing records of 4,296 sows were analyzed using a binomial logistic regression procedure. The model included the fixed effect of farm (1, 2, and 3), year of farrowing (2003–2011), season of farrowing (dry, rainy, and windy), number of pigs born alive at first parity (<9, 9-10, 11-12, and >12 piglets), lactation length (<18, 18–24, and >24 days), and weaning to conception intervals (<4, 4–11, and >11 days). Fifty-five point eight percent of all sows presented a reduced or similar litter size at parity 2. The odds of decrease in the second litter size were 1.56 and 2.01 for farms 2 and 3, respectively. Higher odds were found for sows farrowing during the rainy and dry seasons (1.20 and 1.24, resp.) and for sows with large litters at parity 1 (>12 piglets, odds = 33.2). Sows with weaning to conception intervals <4 days and between 4 and 11 days had higher odds of a decrease in the second litter (1.78 and 2.74 pigs, resp.).

Environmental effects on productive and reproductive performance of Pelibuey ewes in Southeastern México

ABSTRACT The objective of this study was to determine the effect of some environmental factors on reproductive and productive performance traits and to estimate their repeatability in Pelibuey ewes in Yucatan, Mexico. Information of 956 Pelibuey ewes lambing from 2007 to 2013 in three farms were used (n = 2215 lambing). The assessed traits were age at first lambing (AFL), lambing interval (LI), litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB) and litter weight at weaning adjusted to 60 days (LWWA). Mixed models were used to determine the effects of farm, lambing season or birth, year of lambing or birth and parity number on above traits. Repeatability were calculated using the between and within ewe components of variance. Overall means and standard deviations for AFL, LI, LSB, LWB, LSW and LWWA were 526.7 ± 107.1d, 259.4 ± 70.3d, 1.5 ± 0.6, 4.3 ± 1.6 kg, 1.4 ± 0.7 and 19.1 ± 10.1 kg, respectively. Repeatability for LI, LSB, LSW, LWB and LWWA were 0.06 ± 0.20, 0.12 ± 0.04, 0.00 ± 0.04, 0.13 ± 0.04 and 0.01 ± 0.04, respectively. AFL was not affected by any of the environmental factors. However, the other traits were influenced (p < .05) by farm, lambing year, lambing season, parity and LSB (for LI and LSW). In conclusion, productive and reproductive performance traits of Pelibuey ewes were influenced by environmental factors, and repeatability were lows. To improve the performance of Pelibuey ewes adjustments to management schemes should be made as well as to base the selection on more than one productive and reproductive indicator.ABSTRACTThe objective of this study was to determine the effect of some environmental factors on reproductive and productive performance traits and to estimate their repeatability in Pelibuey ewes in Yucatan, Mexico. Information of 956 Pelibuey ewes lambing from 2007 to 2013 in three farms were used (n = 2215 lambing). The assessed traits were age at first lambing (AFL), lambing interval (LI), litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB) and litter weight at weaning adjusted to 60 days (LWWA). Mixed models were used to determine the effects of farm, lambing season or birth, year of lambing or birth and parity number on above traits. Repeatability were calculated using the between and within ewe components of variance. Overall means and standard deviations for AFL, LI, LSB, LWB, LSW and LWWA were 526.7 ± 107.1d, 259.4 ± 70.3d, 1.5 ± 0.6, 4.3 ± 1.6 kg, 1.4 ± 0.7 and 19.1 ± 10.1 kg, respectively. Repeatability for LI, LSB, LSW, LWB and LWWA were 0.06 ± 0.20, 0.12 ± 0...