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The objectives of this study were to describe the growth of young llamas by the application of four non-linear functions (Gompertz, Logistic, Von Bertalanffy and Brody), evaluate the importance of fixed (environmental) effects (sex, type of llama, month and year of birth) on growth curve parameters and finally estimate the genetic parameters for growth curve parameters ( A : asymptotic body weight and k : specific growth rate). A total of 35,691 monthly body weight records from birth up to 16 months of age from 2675 young llamas, collected from 1998 to 2008 in the Quimsachata Experimental Station of the Instituto Nacional de Innovación Agraria (INIA) in Peru were used. Growth curve parameters were estimated by non-linear procedures while genetic parameters were estimated by application of a bivariate animal model and the restricted maximum likelihood (REML) method. All non-linear functions closely fitted actual body weight measurements, while the Gompertz function provided the best fit in describing the growth data of young llamas. All environmental effects significantly influenced the asymptotic weight ( A ), while the specific growth rate ( k ) was only affected by the month and year of birth. Heritability estimates for parameters A and k were 0.10 and 0.01, respectively. Genetic correlation between A and k was high and negative (−0.82), indicating that a rapid decrease in growth rate after inflection point is associated with higher mature weight. Despite the low heritability estimates obtained herein, slight genetic gain(s) were observed in the current study suggesting that a selection program to change the slope of the growth curve of llamas may be feasible. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the study was to compare the ovulatory response and embryo production in llamas (Lama glama) treated with a single dose of equine chorionic gonadotropin (eCG) alone or combined with intravaginal medroxyprogesterone acetate (MPA) at the time of follicular wave emergence. Llamas with a growing follicle ≥7mm in diameter were assigned to one of the following groups: (1) Control (n=28): Nonstimulated llamas were mated and embryos were collected 7 d after mating. (2) eCG (n=32): Llamas were given 5mg luteinizing hormone (LH) (Day 0) to induce ovulation, 1000 IU eCG on Day 2, a luteolytic dose of prostaglandin F2α on Day 6, mating on Day 7, and embryo collection on Day 14. (3) eCG+MPA (n=34): Llamas were treated as those in the eCG group, but a sponge containing 60mg MPA was placed intravaginally from Days 2 to 6. Llamas that did not respond to synchronization or superstimulation were excluded, leaving data from n=26, 26, and 27 in the control, eCG, and eCG+MPA groups, respectively, for statistical analysis. The mean (±SD) number of follicles>7mm at the time of mating was greatest in the eCG group, intermediate in the eCG+MPA group, and lowest in the control group (16.6±5.3, 12.9±3.7, and 1.0±0.0, respectively, P<0.001). The number of corpora lutea was similar between eCG and eCG+MPA groups (10.1±2.9 and 8.6±3.7, respectively); both were higher (P<0.001) than in controls (0.9±0.3). The number of embryos did not differ significantly between the eCG and eCG+MPA groups (4.8±2.8 and 3.5±3.0, respectively), but both were higher (P<0.001) than in the controls (0.7±0.4). In conclusion, eCG, with or without MPA effectively induced a superovulatory response and multiple embryo production in llamas. [Copyright &y& Elsevier]

Abstract: An experimental trial of the segregation of white vs. pigmented and black vs. brown colours in alpacas was conducted at the Peruvian INIA Quimsachata Experimental Station. One hundred and forty five offspring were born from the following matings: 4 white sires×36 white dams, 4 white sires×39 pigmented dams, and 9 pigmented sires×70 pigmented dams. Among these last matings were, 4 black sires×25 black dams, 2 black sires×20 brown dams, and 3 brown sires×25 brown dams. Statistical tests validate that the inheritance of white is due to a single gene which is dominant over pigmentation, without any modifying effect and independent of segregation of black and brown patterns. However, the evidence does not support a simple dominant inheritance of the black vs. brown. [Copyright &y& Elsevier]

Research with humans and non-human primate species has found an association between social rank and individual health. Among humans, a robust literature in industrial societies has shown that each step down the rank hierarchy is associated with increased morbidity and mortality. Here, we present supportive evidence for the social gradient in health drawing on data from 289 men (18+ years of age) from a society of foragers-farmers in the Bolivian Amazon (Tsimane'). We use a measure of social rank that captures the locally perceived position of a man in the hierarchy of important people in a village. In multivariate regression analysis we found a positive and statistically significant association between social rank and three standard indicators of nutritional status: body mass index (BMI), mid-arm circumference, and the sum of four skinfolds. Results persisted after controlling for material and psychosocial pathways that have been shown to mediate the association between individual socioeconomic status and health in industrial societies. Future research should explore locally-relevant psychosocial factors that may mediate the association between social status and health in non-industrial societies. [ABSTRACT FROM AUTHOR]