Browsing by Author "Bas, Fernando"

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    Adaptation strategies based on the historical evolution for dairy production systems in temperate areas: A case study approach
    (2020) Toro-Mujica, Paula; Vera, Raul; Pinedo, Pablo; Bas, Fernando; Enriquez-Hidalgo, Daniel; Vargas-Bello-Perez, Einar
    Dairy production systems are heterogeneous as they are influenced by farm location and structure, markets, environmental conditions, and the producers' preferences and peculiarities. A typology of the existing dairy systems in Chile was developed with the objective of identifying homogenous groups that would allow for the characterization of adaptation strategies to changing environmental, social, technological, political and economic variables. Multivariate analyses were performed on data from official surveys carried out in 2009, 2011, 2013, and 2015. Six groups (I-VI) were identified representing 26.9%, 21.5%, 21.6%, 14.6%, 6.8% and 8.6% of the population surveyed. Group I was the largest, and it included non-specialized commercial dairies. Group II clustered semi-extensive, medium to large dairies that rely mostly on high yielding improved pastures. Group III included small, semi-extensive commercial farms that make a more intense use of pastoral resources, such as sown pastures and improved native grasslands. Groups IV, V, and VI corresponded to specialized dairies, highly market-oriented, that use annual forages to supplement intensively managed and planned pastures, but that differ in size and some management strategies. The observed temporal changes and adaptations over time were closely linked to farm size, intensity in the use of various technologies, the number and the breed of the dairy cows, and the presence of other agricultural activities in the property. The effect of variable prices of milk and system inputs differed by group. Given the social and economic importance of dairies throughout Central and Southern Chile, a number of interventions are proposed, including technical modifications, extension initiatives, and changes in policies.
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    Endocrine changes during pregnancy, parturition and post-partum in guanacos (Lama guanicoe)
    (ELSEVIER SCIENCE BV, 2009) Luis Riveros, Jose; Urquieta, Bessie; Bonacic, Cristian; Hoffmann, Bernd; Bas, Fernando; Schuler, Gerhard
    Plasma concentrations of progesterone (P4), estradiol-17 beta (E2), estrone (E1) and estrone sulfate (E1S) were measured during gestation in eight guanacos kept in captivity. Gestational length was 346.1 +/- 9.8 days. P4 plasma concentrations increased after ovulation and remained elevated until parturition. However, during the last 4 weeks of gestation, a gradual decrease from 4.17 x 1.17(+/- 1) nmol/L to 2.02 x 1.95(+/- 1) nmol/L on day 5 before parturition was observed, followed by a more abrupt final decline to baseline concentrations which were reached on the day after parturition. Mean E2 plasma concentrations started to increase during the eighth month of gestation, and were significantly elevated up to maximum concentrations of 484.7 x 1.21(+/- 1) pmol/L during the last 2 months of pregnancy. Concentrations returned to baseline during the last 2 days of gestation. An increase of E1S concentrations (p < 0.01) was observed in the eleventh month of gestation. Mean El S concentrations remained rather constant during the last 3 weeks of gestation between 4 to 8 nmol/L until parturition, when a steep precipitous decline was observed. E1 concentrations were slightly elevated during the last 4 weeks of gestation, however, maximum concentrations did not exceed 1.5 nmol/L The results show distinct species specific features of gestational steroid hormone profiles in the guanaco in comparison to domestic South American camelids, such as a more pronounced gradual prepartal decrease of P4 concentrations prior to the final decline to baseline, and clearly lesser EIS concentrations during the last 4 weeks of gestation, which lack a continuous prepartal increase. (C) 2009 Elsevier B.V. All rights reserved.
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    Meat Consumers' Opinion Regarding Unhealthy Pigs: Should They Be Treated with Antibiotics or Euthanized on Farm?
    (2021) Lemos Teixeira, Dayane; Enriquez-Hidalgo, Daniel; Estay Espinoza, Tamara; Bas, Fernando; Hotzel, Maria Jose
    The aim of this study was to investigate the opinions of meat consumers (n = 1780) on on-farm management of unhealthy pigs, whether support for treatment with antibiotics varies according with chance of recovery, and the effect of knowledge on the use of antibiotics on these opinions. Most participants believed that the use of antibiotics was the best solution for unhealthy pigs, and this was associated with a low level of knowledge about antibiotics. Increasing the probability of recovery after treatment increased support for treating pigs with antibiotics. However, the majority of participants rejected the consumption of meat from animals housed in "hospital pens". After price, concern with food safety was the second main factor that influenced participants' choice when buying meat. Support for the use of antibiotics to deal with unhealthy pigs in "hospital pens", as well as for consumption of the meat from these animals, was higher among participants involved in agriculture. This shows that consumers are unaware of the potential negative repercussions for animal welfare associated with banning or reducing the use of antibiotics in livestock production, which is an important concern for the industry.
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    Nutrient absorption, feed intake and liveweight change as a consequence of Roux-en-Y gastric bypass with increasing alimentary limb lengths in the pig model
    (2011) Gandarillas, Monica; Boza, Camilo; Barrales, Luis; Marie Hodgkinson, Suzanne; Bas, Fernando
    M. Gandarillas, C. Boza, S.M. Hodgkinson, L. Barrales, and F. Bas. 2011. Nutrient absorption, feed intake and liveweight change as a consequence of Roux-en-Y gastric bypass with increasing alimentary limb lengths in the pig model. Cien. Inv. Agr. 38(1): 31-39. Roux-en Y gastric bypass (RYGBP) combines a restrictive and malabsortive component of the digestive system. Metabolic outcomes of increasing the latter, is a matter of research interest. The aim of this study was to evaluate the nutritional consequences of RYGBP with different alimentary limb lengths using a pig model. Twenty-six pigs were randomly assigned to four laparoscopic procedures: RYGBP with 300 cm of alimentary limb (1300); RYGBP with 600 cm (1600); RYGBP with 900 cm (T900); sham operation (TS). RYGBP consisted of creating a proximal gastric pouch with a 300, 600 and 900 cm alimentary limb. Sham operation was performed by bowel transections and reanastomosis in the ileum and proximal jejunum together with gastrotomy and closure. Animals were evaluated weekly for weight increase and monthly for food intake. Eighteen weeks after surgery, fecal in vivo apparent digestibility of protein, fat, fiber, calcium and phosphorous were determined. We performed ANOVA and Tukcy tests to detect differences in weight, feed intake and digestibility. We observed significant differences in liveweight after 10 weeks among T300, 1600 and T900 as compared to TS. No differences were found among T300, T600 and 1900. We also observed significant differences in feed intake among 1300, T600 and T900 versus TS. No differences among treatments for digestibility of fat; fiber; protein and energy were found. Calcium and phosphorous apparent digestibility differed among treatments. RYGBP reduced weight increase in the porcine model and calcium and phosphorous digestibility was reduced with longer limbs.