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| Author(s): |
Fábio Luís Henrique
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT) |
| Defense date: | 2015-02-11 |
| Examining board members: |
Cristiane Gonçalves Titto;
Flávio Moreno Salvador;
Adroaldo José Zanella
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| Advisor: | Cristiane Gonçalves Titto |
| Abstract | |
This study was developed with the objective to investigate the possible influence of gestational stress by inducing Lipopolysaccharide (E. coli) on maternal and filial relationship performance of the lamb, as well as the stress of weaning on feedlot performance and on characteristicsin housing. Running the experiment took place from December 2013 to July 2014 in the Annex to Biometeorology and Ethology Laboratory located in goat and sheep production sector of Administrative Campus Hall, Universidade de São Paulo in Pirassununga-SP. We used 43 multiparous sheep, crossbred Santa Inês and 55 lambs, calves from AIFT those sheep with male White Dorper semen. The experimental design was completely randomized having a 3 x 2 factorial as the distribution pattern of treatments consists of 3 groups during pregnancy (control (Cg), application of LPS to 70 (± 7) days of gestation (Ig) and at 120 (± 7) days of gestation (Fg)) combined with two types of weaning (controlled weaning (Cw) and abrupt weaning (Aw)). Means were compared by F test and Student\'s t test (PDIFF), with a 5% significance level. In the first experiment the objective was to analyze the influence of stress, generated by the use of LPS in different gestational periods on the levels of cortisol and body temperature of sheep, filial maternal behavior, cortisol levels immediately after parturition, birth weight (BW) of the lambs and the time spent for the first feeding. The animals were allotted in three groups: Cg, Ig and Fg. In the middle stage of pregnancy, analyzing the circadian rhythm of cortisol and RT for the treatment Cg and Ig by the interaction between treatment and time showed higher cortisol levels to Ig and RT (P<0.05). In the final stage with the same interaction between treatment and time increased cortisol and temperature values during the circadian rhythm were Fg (P<0.05). For the evaluation of filial maternal behavior, observations of the postures and activities of both the sheep when the lambs were analyzed by the interaction between treatment and type of delivery (P<0.05). There was also an interaction between treatment and the type of parturition to the time the first feeding with the Fg treatment in dual labor situation presented as long, not being different only Ig treatment also double parturition (P<0.05). Analyzing the BW, the interaction occurred between treatment and sex with the lowest values observed for Fg treatment compared to the other treatments (P<0.05). LPS altered levels of cortisol during the circadian rhythm, and stress during pregnancy the influenced filial maternal behavior. The animals subjected to stress during the final third of gestation had higher expenditure of time to ingest colostrum and lighter weights at birth. In the second experiment the objective was to evaluate the efficiency of the subsidiary or abrupt weaning to reduce the impact of stress during pregnancy in relation to the performance of lambs. We used 47 lambs, 22 male and 25 female, comprised of 6 treatments: CgCw, CgAw, IgCw, IgAw, FgCw and FgAw. Blood cortisol levels were analyzed and the TR controlled weaning and the comparison between the two types of weaning, weaning weight (WW) and performance data in confinement for dry matter intake (DMI), feed conversion (FC), feed efficiency (FE), average daily gain (ADG) and post-slaughter measures. There was fixed effect of stress during pregnancy and days to cortisol levels during the Cw (P<0.05) for the rectal temperature was observed fixed effect sex, day and time (P<0.05). On receipt of the animals was fixed effect confined in time (during harvest day) and type of weaning, with higher cortisol values for the first harvest day (P<0.05) and the abrupt weaning compared with controlled (P<0.05) in the same day for the TR was observed fixed effect of time, the first harvest less than the others (P<0.05). At harvest 24 hours and 48 hours after entering of animals in the feedlot had higher cortisol levels than Cw (P<0.05) and made opposite was observed for TR. Dc showed higher weaning weight that Aw (P<0.05). There was interaction between stress during pregnancy and sex for DMI and ADG, with lower values for males of Gf (P<0.05), with no significant differences for FC and FE in any treatment. In analysis post - slaughter, the lowest values were observed for Fg and Aw. From Controlled weaning can reduce the effects of stress during pregnancy, improving the performance of lambs males, and lambs when challenged in late pregnancy are more susceptible than females. (AU) | |
| FAPESP's process: | 13/08180-8 - Stress during pregnancy and weaning and its influence on the performance of lambs |
| Grantee: | Fábio Luís Henrique |
| Support Opportunities: | Scholarships in Brazil - Master |