Foliar mineral content of five shrub species with nutritional potential for small ruminants in semiarid regions in northeastern Mexico / Conteúdo mineral foliar de cinco espécies de arbustos com potencial nutricional para pequenos ruminantes em regiões semiáridas do nordeste do México

ABSTRACT: This study was conducted to determine the monthly composition of the minerals Ca, P, K, Mg, Cu, Fe, Mn and Zn in five shrub species that are consumed by small ruminants in the semi-arid regions of northeastern Mexico. Leaves samples of shrub species; Celtis pallida, Croton suaveolens, Forestiera angustifolia, Guaiacum angustifolium and Parkinsonia aculeata were randomly collected during twelve consecutive months from July 2018 to June 2019 in two sites, located in Linares and Los Ramones counties, in the state of Nuevo Leon, Mexico. Mineral content was analyzed using an atomic absorption spectrophotometer, while phosphorus was measured by the colorimetry method. The Linares county showed the highest content of macro- and micro-minerals. Among species, C. pallida showed the highest values of macro-minerals and P. aculeata content of micro-minerals was highest. Ca (total mean = 40.0 g kg-1 DM), K (15.4 g kg-1), Mg (3.7 g kg-1), Fe (87.2 mg kg-1), Mn (35.5 mg kg-1) were available in adequate quantities, while P (1.3 g kg-1 DM), Cu (6.4 mg kg-1) and Zn (17.7 mg kg-1) were found deficient. Shrub species in this study can be considered as a good source of Ca, K, Mg, Fe and Mn except in C. suaveolens. However, P, Cu and Zn must be supplemented.

RESUMO: O presente estudo foi realizado com o intuito de determinar os teores dos minerais Ca, P, K, Mg, Cu, Fe, Mn e Zn, ao longo do ano, em cinco espécies de arbustos consumidas por pequenos ruminantes nas regiões semiáridas do nordeste do México. Amostras de folhas de espécies arbustivas; Celtis pallida, Croton suaveolens, Forestiera angustifolia, Guaiacum angustifolium e Parkinsonia aculeata foram coletadas aleatoriamente durante doze meses consecutivos, de Julho de 2018 a Junho de 2019, em dois locais, nos municípios de Linares e Los Ramones, no estado de Nuevo Leon, México. O conteúdo mineral foi analisado através de um espectrofotômetro de absorção atômica, enquanto o fósforo foi medido pelo método da colorimetria. O município de Linares apresentou o maior conteúdo de macro e microminerais. Entre as espécies, C. pallida apresentou os maiores valores de macrominerais, enquanto o teor de microminerais foi maior na P. aculeata. Ca (média = 40.0 g kg-1 MS), K (15.4 g kg-1), Mg (3.7 g kg-1), Fe (87.2 mg kg-1), Mn (35.5 mg kg-1) estavam disponíveis em quantidades adequadas, enquanto P (1.3 g kg-1 MS), Cu (6.4 mg kg-1) e Zn (17.7 mg kg-1) foram encontrados deficientes. As espécies arbustivas deste estudo podem ser consideradas uma boa fonte de Ca, K, Mg, Fe e Mn, exceto na espécie C. suaveolens. No entanto, P, Cu e Zn devem ser suplementados.

Social dominance affects the development of sexual behaviour but not semen output in yearling bucks.

Goats are polygynous seasonal mammals that establish dominant-subordinate relationships, especially in bucks. The aims of this study were to: 1) compare the reproductive development of dominant and subordinate young bucks allocated in dyads, and 2) determine if their previous dominant position affect their response to grouping. Twenty-four young bucks were allocated in dyads when they were 4 mo old, and the dominance position (DP) [dominant (DB) or subordinate buck (SB)] was determined with a test of competition for food. Body weight, scrotal circumference, semen quality and sexual behaviour toward an oestrous ewe were weekly determined during 8 weeks beginning when the bucks were 8 mo old. Body weight, scrotal circumference, and seminal parameters were not affected by DP. Dominant bucks tended to begin sexual courtship earlier than SB bucks (P = .09), but displayed less flehmen (P = .0008) and tended to display less ano-genital sniffings (P = .053). However, DB bucks displayed more lateral approaches (P = .019), attempted to mount, mounted, and mated the oestrous doe more times (P < .0001, P = .0002 and P < .0001, respectively) than SB bucks. In the 9th week, all the bucks were grouped, cortisol and testosterone serum concentrations were measured, and agonistic and sexual behaviour between bucks were recorded during the first day. Semen was collected and evaluated 4 and 9 days after grouping. Cortisol concentration increased (P = .037), but testosterone decreased (P < .0001), after grouping the animals, without differences according to their DP. The DB tended to display more lateral approaches toward other bucks than SB bucks (P = .06), but there were no effects of DP in any other behaviour. Sperm concentration and the total number of sperm in the ejaculate decreased after grouping (P = .01 and P = .009 respectively. In conclusion, in the conditions of this study, dominance relationships affected sexual behaviour but not body or testicular size or semen output in young bucks allocated in dyads. Dominant bucks were more effective displaying sexual consummatory behaviours. Grouping all the bucks together displayed a strong stress response that affected testosterone secretion and sperm output which was of similar magnitude in bucks that were dominant or subordinate individuals before.