Browsing by Author "Zapata, Beatriz"

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    Allosuckling allows growing offspring to compensate for insufficient maternal milk in farmed guanacos (Lama guanicoe)
    (2010) Zapata, Beatriz; Correa, Loreto; Soto-Gamboa, Mauricio; Latorre, Etel; Gonzalez, Benito A.; Ebensperger, Luis A.
    While allonursing, the provision of milk to non-offspring by females, involves a potential cost to their own offspring, allosuckling, the suckling from females other than their own mother may allow offspring to compensate for previous deficiencies in maternal milk. We tested this hypothesis in farmed guanacos. Under the compensation hypothesis we predicted that mothers of calves exhibiting allosuckling should be in poorer physical condition and should exhibit relatively low acceptance rates to filial sucking attempts compared to mothers whose calf did not allosuckle. We also predicted that calves exhibiting frequent allosuckling should show similar or greater rates of gain in body weight. but similar total (or final) weight in the long term than calves that nursed from their mothers exclusively. We examined the potential effects of sex and order of birth dates of calves on allosuckling, and the effect of female Success during agonistic encounters with other females on allonursing. Two stable groups of 15 and 14 mother-offspring pairs of farmed guanacos were studied from birth to approximately 3 months of age. Allosuckling events comprised 5.7% of all suckling events. Allonursing was performed by 52% of dams and 62% of calves exhibited allosuckling. We found similar gain rates in body weight and total weight at 60 days of age between allosuckling calves and filial sucking calves, irrespective of whether their mothers allonursed or not (P > 0.1). Body weight of mothers whose calf allosuckled was significantly lower than that of mothers whose calves nursed from them exclusively (P = 0.02). In addition, the percentage of acceptance of filial suckling bouts was significantly lower for allosuckling calves (P = 0.004). There was no correlation between the frequency of allonursing and the success of dams during agonistic encounters (P > 0.22). Our findings are consistent with the hypothesis that guanaco calves used allosucking to compensate for previous deficiencies in maternal milk. (C) 2009 Elsevier B.V. All rights reserved.
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    Molecular genetic evidence for social group disruption of wild vicunas Vicugna vicugna captured for wool harvest in Chile
    (ELSEVIER, 2009) Sarno, Ronald J.; Gonzalez, Benito A.; Bonacic, Cristian; Zapata, Beatriz; O'Brien, Stephen J.; Johnson, Warren E.
    Since 1994 wild vicunas have been captured and shorn for their wool, yet, there remains a noticeable lack of data regarding the possible influence of capture and shearing upon vicuna biology. Therefore, we assessed post-capture group composition, genetic relatedness, and paternity among animals that were captured for live shearing and release. We captured twenty-six groups (134 animals) on the Chilean Altiplano. Seventy-three percent of Male Groups (designated prior to chase) contained exclusively adult males upon capture,whereas remaining "Male Groups" contained crias and/or adult females and crias. Forty-seven percent of Family Groups (designated prior to chase) contained I adult male, adult females, and the number of crias <= the number of adult females. Remaining Family Groups contained no or multiple adult males, and more crias than adult females. Average relatedness among all vicunas was -0.007. Paternity analysis revealed that 35% of crias were captured with their biological mother and that only 1 cria was captured with both biological parents. Based on previous observations of group composition in the wild, animals from different groups may separate and/or mix during the chasing stage. Improvement of the chasing technique and instituting a post-capture monitoring program may aid in the detection of medium- and long-term impacts regarding group stability, cria survival, and ultimately wool production. (C) 2009 Elsevier B.V. All rights reserved.