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The use of fruit by-products such as citrus pulp represents a feeding ingredient that deserves to be evaluated as an energy source in animal rations. Thirty-six British breed steers were allotted to one of the three feeding treatments (12 steers/treatment): 0%, 15% and 30% of fresh citrus pulp inclusion in the ration in a randomized complete block design to evaluate animal performance and carcass and meat quality traits. In the present study, the inclusion of fresh citrus pulp up to 30% of the diet did not affect the animal average daily gain (p > 0.05) but steers that were fed the pulp consumed less feed (p < 0.05) and presented a lower feed conversion ratio (p < 0.05) than their counterparts without citrus pulp in their diet. No effect of fresh citrus pulp was observed on carcass and meat quality (p > 0.05). A greater lipophilic antioxidant capacity (p < 0.05) in meat was observed when fresh citrus pulp was offered at 15% of the diet. Fresh citrus pulp used up to 30% as a feed ingredient in feedlot rations does not negatively affect animal performance or meat quality but, rather, has a positive effect on dry matter intake and a better feed conversion ratio.

Multiparous Aberdeen Angus · Hereford crossbred cows were used to evaluate the effect of supplementation during the last month of gestation on milk production and composition and cow and calf performance. Cows were assigned randomly to supplement (SUP; n = 18) or Control (CON; n = 17) treatments. Supplemented cows were offered (1 kg/100 kg bodyweight) a mix of sorghum grain and protein concentrated (67 : 33 as-fed basis; 16% crude protein, 11% acid detergent fibre) from (mean AE s.e.m.) 33 AE 1.4 days prepartum until calving. Before, during, and after the supplementation period, cows grazed together a native pasture paddock with average forage mass available of 1345 kg/ha of dry matter (10.4% crude protein, 45.2% acid detergent fibre). Cows were blood sampled weekly from -42 to 112 days postpartum (DPP) for serum progesterone and non-esterified fatty acids (NEFA) concentrations. Maximum follicle diameter was measured by ovarian ultrasound examination at 60 DPP. The breeding period lasted 60 days and started at 60 AE 1.4 DPP. There was an interaction between treatment and time on BCS (P < 0.0005). Before calving there were no differences in BCS between cows in SUP and in CON, but at calving SUP cows tended (P = 0.10) to present greater BCS and from calving to 84 DPP BCS was greater (P < 0.05) in SUP with respect to CON cows. There was an interaction between treatment and time on plasma NEFA concentrations (P < 0.0005). During the last month of gestation NEFA concentrations were reduced in SUP cows but there were no differences between treatments during the postpartum period. Milk production decreased linearly from 30 to 150 DPP but there was no effect of treatment on it. Calf bodyweight at birth and at weaning did not differ between treatments (37.5 AE 2.4 and 175.6 AE 2.4 kg, respectively). The probability of cows presenting follicles with diameter !10 mm was greater (P < 0.05) in SUP than CON cows. The length of the postpartum period did not differ between treatments. The probability of cows cycling during the first 90 DPP and pregnancy rate tended (P = 0.08) to be greater in SUP than in CON cows. Supplementation in winter and for only 30 days in the last month of gestation of beef cows under grazing conditions, increased cows' BCS without increasing BW of calves, and tended to improve reproductive performance.

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Este volumen colegiado por veintitrés autores es el primer enfoque comprensivo sobre la biología de estos roedores que incluye las ratas topo, zokores, tuco-tucos y, de nuestro particular interés zoogeográfico, los geómidos. Aunque todos los biólogos de campo, independientemente de nuestras personales disciplinas, hemos visto y experimentado la actividad de los roedores, no es hasta la lectura de este libro que se aprende del curioso mundo de estos habitantes subterráneos que no solo han desarrollado morfologías muy adaptadas al medio de las galerías sino interesantes adaptaciones fisiológicas al medio de la oscuridad y microambientes bajo el suelo. El libro está dividido en tres secciones: Biología, ecología y evolución de los roedores, importantes modificadores estructurales de los suelos y de la rizósfera en todas sus partes y no menos importantes en la distribución de propágulos de la cobertura vegetal del globo. Con excepción de un tratamiento filogenético del grupo y a nivel del género, la obra no pre-senta aspectos sistemático-taxonómicos. Con la calidad gráfica que caracteriza a la editorial de la Universidad de Chicago, esta es una obra que enriquecerá las bibliotecas de mastozoólogos, ecólogos y aficionados serios a los estudios naturales. Lacey, E.A., J.L. Patton and G.N. Cameron. (eds.). 2000. Life underground. The biology of subterranean rodents. Dentro de la producción de literatura cien-tífica en Latinoamérica, lastimosamente conti-núan publicándose obras que nos condenan a la imposibilidad de evadir el calificativo de ha-cedores de ciencia subdesarrollada o tercer-mundista por parte de un extenso sector de la comunidad científica internacional. "Guía de las serpientes de Honduras" es un ejemplo ine-quívoco de esta particular situación, donde se conjugan una serie de "pecados" o errores fun-damentales (y ciertamente imperdonables) que se arrastran desde la génesis misma del proyec-to. Se supone que la realización de un libro de esta naturaleza debiera contar con un cúmulo aceptable de experiencia en el campo específi-co por parte del autor o autores, una minuciosa y actualizada revisión bibliográfica como apo-yo complementario y una producción editorial adecuada. Adicionalmente, la participación a ni-vel crítico de otros especialistas a quienes el au-tor debiera acudir, puede generar un grado salu-dable de maduración al manuscrito, así como