Manuel González-Ronquillo

Chemical composition and fermentation characteristics of grain and different parts of the stover from maize land races harvested at different growing periods in two zones of central Mexico

Abstract The objective of this work was to determine the rumen fermentation characteristics of maize land races used as foragein central Mexico. In vitro gas production (ml per 200mg dry matter (DM)) incubations were carried out, and cumulativegas volumes were fitted to the Krishnamoorthy et al. (1991) model. The trial used a split-plot design with cultivationpractices associated with maize colour (COL) as the main plot with three levels: white, yellow and black maize; growingperiods (PER) were the split plots where PER1, PER2 and PER3 represented the first, second and third periods,respectively and two contrasting zones (Z1 ¼ valley and Z2 ¼ mountain) were used as blocking factors. The principaleffects observed were associated with the maturity of the plants and potential gas production increased (P , 0·05) instems (PER1 ¼ 51·8, PER2 ¼ 56·3, PER3 ¼ 58·4ml per 200mg DM) and in whole plant (PER1 ¼ 60·9, PER2 ¼ 60·8,PER3 ¼ 70·9ml per 200mg DM). An inverse effect was observed with fermentation rates in leaves (P , 0·01) with0·061, 0·053 and 0·0509 (per h) and in whole plant (P , 0·05) with 0·068, 0·057, 0·050 (per h) in PER1, PER2 andPER3 respectively. The digestibility of the neutral-detergent fibre (NDF) decreased with maturity especially in leaves(P , 0·05) with values of 0·71, 0·67 and 0·66g/kg; in rachis (P , 0·01) 0·75, 0·72, and 0·65 in PER1, PER2 and PER3respectively. The NDF content in leaves in leaves (668, 705 and 713g/kg DM for PER1, PER2 and PER3,respectively), stems (580, 594 and 644g/kg DM) and, husk (663, 774 and, 808g/kg DM) increased (P , 0·05) withincreasing plant maturity, rachis were significantly different between periods (P , 0·01). The structure with the bestnutritive characteristics was the husk, because it had the lowest fibre contents, especially in acid-detergent lignin, withvalues of 22·6, 28·6 and 37·6g/kg DM in PER1, PER2 and PER3, respectively.Keywords: gas production, highlands, maize, stover, small farms.

Digestible energy requirements of Mexican donkeys fed oat straw and maize stover.

The limited availability of food, together with the constraints that traditional management systems impose on the natural foraging behaviour of donkeys, often results in severe under-nutrition. Few studies have been conducted into the digestibility of different forages and little information exists on nutritional requirements of donkeys. In order to measure digestible energy requirements of donkeys under tropical conditions, an experiment was carried out at the Centre for Research in Agricultural Science (CICA) and the Faculty of Veterinary Medicine of the Universidad Autónoma del Estado de México located in the Toluca valley, Central México. Thirty-two donkeys of a body condition typical for Central México were divided into four groups of 8 animals each according to their sex and live weight: group 1 (Gl) comprised male donkeys below the average body weight (102 ± 5 kg); group 2 (G2) comprised male donkeys of average body weight (121.5 ± 4 kg); group 3 (G3) comprised female donkeys below average weight (111.8 ± 5 kg); and group 4 (G4) comprised female donkeys of average weight (127.6 ± 5 kg). A diet of oat straw or maize stover and 15% alfalfa hay was offered to meet exact maintenance requirements. The donkeys were monitored for 13 months. The live weight of all animals was recorded daily in order to monitor whether maintenance requirements were being met. Mean daily digestible energy (DE) requirements were measured during the winter, spring, summer and autumn of 2003–2004. Digestible energy requirements of all four sex and liveweight groups were significantly (p > 0.05) higher during the spring than during the other seasons of the year (13.5, 18.0, 10.4 and 14.3 MJ DE per day during winter, spring, summer and autumn, respectively). Predicted DE requirements of donkeys with a live weight range betweenn 90 and 150 kg using the data from the present study were less than those predicted using scaled-down horse feeding standards.

Comparison of mathematical models applied to f1 dairy sheep lactations in organic farm and environmental factors affecting lactation curve parameter.

The objective of this study was to compare the goodness of fit of four lactation curve models: Wood’s Gamma model (WD), Wilmink (WL), and Pollott’s multiplicative two (POL2) and three parameters (POL3) and to determine the environmental factors affecting the complete lactation curve of F1 dairy sheep under organic management. A total of 5,382 weekly milk yields records from 150 ewes, under organic management were used. Residual mean square (RMS), determination coefficients (R2), and correlation (r) analysis were used as an indicator of goodness of fit for each model. WL model best fitted the lactation curves as indicated by the lower RMS values (0.019), followed by WD (0.023), POL2 (0.025) and POL3 (0.029). The four models provided total milk yield (TMY) estimations that were highly correlated (0.93 to 0.97) with observed TMY (89.9 kg). The four models under estimated peak yield (PY), whereas POL2 and POL3 gave nearer peak time lactation estimations. Ewes lambing in autumn had higher TMY and showed a typical curve shape. Higher TMY were recorded in second and third lambing. Season of lambing, number of lambing and type of lambing had a great influenced over TMY shaping the complete lactation curve of F1 dairy sheep. In general terms WL model showed the best fit to the F1 dairy sheep lactation curve under organic management.

Evaluation of chromium oxide and titanium dioxide as inert markers for calculating apparent digestibility in sheep

ABSTRACT The objective of the present study was to evaluate two markers: chromium oxide (Cr2O3) and titanium dioxide (TiO2). We evaluate the interaction between Cr2O3 and TiO2, and the techniques used to determine it, using atomic absorption spectrophotometry (AAS) and photometry simple (PS). We used six growing sheep distributed in a replicated Latin square 3 × 3 design, with adjustment for the residual error effect. The TiO2 and Cr2O3–TiO2 produced values similar to those obtained by total faecal collection (TFC) or the use of Cr2O3 alone, determined by AAS and PS. Digestibility of the marker/TFC ratio was similar (p > .05) between markers and technique. The use of TiO2 alone or in combination with Cr2O3 seems to be a suitable alternative to TFC and Cr2O3 to calculate apparent digestibility of the total digestive tract determined in sheep by PS and AAS.

Effect of field pea (Pisum sativum L.) level on intake, digestion, ruminal fermentation and in vitro gas production in sheep fed maintenance diets

The objective of this study was the characterization of the nutritive value, ruminal fermentation and nutrient digestibility of field pea (Pisum sativum L.) hay (FPH) by-product through in situ, in vitro and in vivo tests. A FPH diet was administered ad libitum to four sheep (live weight (LW) 38.0 ± 2.0 kg) at four inclusion levels (0, 25, 50 and 75%) over a conventional sorghum grain/oat straw ration in a 4 × 4 Latin square design. The in situ degradability of FPH was 67% dry matter (DM), 71% crude protein and 66% neutral detergent fiber (NDF). The inclusion of FPH did not affect (P ≥ 0.05) the DM (61 ± 0.4 g/LW(0.75) /day) and organic matter (OM) intake (56 ± 0.7 g/LW(0.75) /day). Total DM digestibility (68 ± 2.5%), OM (70 ± 3%), and NDF (60 ± 3%), were not different (P ≥ 0.05) between control and FPH inclusion diets. The diet had no effect on ruminal pH, ruminal ammonia concentration, total and individual volatile fatty acids. The chemical composition and sheep intake behavior indicate that FPH by-product is medium quality forage when incorporated in maintenance rations.

Participatory study on feeding strategies for working donkeys used by Campesino farmers in the highlands of central Mexico.

The aim of this work was to describe the feeding strategies for donkeys used by peasant farmers in central México. Feeding strategies for the dry and wet seasons are described, as well as the nutritional characteristics of the main forages and supplements used by the farmers. The extent to which the feeding practices used by farmers matched the digestible energy and crude protein requirements of donkeys for maintenance and work was determined. It was concluded that grazing on native grassland could provide enough energy and protein for donkeys at maintenance level and for those performing only a moderate amount of work. More research in required in order to have better estimates of intake and plant species preferred by donkeys under prevailing grazing conditions.

Effect of Physiological Status on Endogenous Excretion of Purine Derivatives in Cattle

The present study examined the endogenous urinary excretion of purine derivatives (PD: allantoin and uric acid) in normally fed animals in different physiological states. Animals fitted with a simple rumen cannula and a T-shaped duodenal cannula were used in three separate experiments. In Experiment I, three heifers (about 8 months old; 225 ±4.4 kg) fed a cereal based diet were used. In Experiment II, two Friesian dry cows (about 24 months old; 696 ±21 kg) fed at maintenance level on chopped barley straw and barley grain (50:50). In Experiment 3, three multiparous crossbreed Holstein-Friesian cows (560 ±10 kg, average milk yield 25 ±3.2 kg/d) in their third lactation were used. The cows were fed a mixed diet (48:52; roughage: concentrate). 15N ammonium phosphate was infused continuously into the rumen to label microbial purine bases (PB). Duodenal flow of digesta and PB was determined using a dual marker system. After 72–80 h purine enrichment had reached plateau values in body pools and in urine. Daily endogenous PD excretion (µmol/W0.75) obtained in dry cows (310 ±31.0) were not significantly different from that obtained in growing steers (236 ±6.0) but were consistently higher (512.4 ±36.4) in lactating cows.

A comparison of processed sorghum grain using different digestion techniques

ABSTRACT This study compares in situ, in vitro (DaisyII and gas production) and in vivo techniques to estimate the degradation of dry matter (DM), organic matter (OM), and N of sorghum grain. We used whole dried sorghum (WDS), dry cracked sorghum (DCS), the reconstituted whole sorghum silage (WSS) and reconstituted cracked sorghum silage (CSS). The residues obtained from the ruminal digestion in vitro (DaisyII) and in situ were analysed for their intestinal digestion (pepsin–pancreatin). OM was similar (981.32 ± 0.52) in all treatments, WSS showed the highest (P < .001) crude protein (CP) concentration compared with the other treatments, whereas CSS showed the highest amount of starch (P < .001) compared to other treatments. The apparent degraded substrate (ADS) was higher (P < .038) for whole sorghums, rumen degradable protein (RDP) was higher for WDS and WSS (P = .003), while protein digestible in the intestine (PDI) was higher for sorghums silage (P < .001) compared with dry sorghums. ADS was higher (P < .022) using the in sacco technique compared with the other methods, while for the RDP and PDI methods in sacco and in vitro (Daisy) showed the better degradation compared with in vivo. The reconstituted ensiling sorghum grains had a favourable response in the availability of nutrients, compared with dried sorghums.

Modelo Virtual Tridimensional de la Articulación Cubital del Perro a Partir de Cortes Plastinados Ultradelgados

RESUMEN: La articulación cubital del perro es de tipo compuesta, formada por el cóndilo del húmero, la cabeza del radio y la escotadura troclear de la ulna. Esta articulación es propensa a padecer enfermedades del desarrollo, lesiones traumáticas y degenerativas. La corrección de estos padecimientos suele ser quirúrgica, sin embargo, el planteamiento de la cirugía resulta d ifícil debido a la complejidad estructural de esta articulación. Los modelos anatómicos tridimensionales (3D) obtenidos de los cortes seriados mediante tomografía computarizada han probado ser eficaces en el planteamiento de los abordajes quirúrgicos, sin embar go tiene limitaciones técnicas en la identificación de los tejidos blandos. Los cortes ultradelgados (1 mm) obtenidos mediante pla stin ción permiten realizar descripciones anatómicas detalladas de regiones anatómicas complejas y también pueden ser usadas para realiza r reconstrucciones 3D. El objetivo del presente trabajo, ha sido obtener una reconstrucción 3D de las estructuras anatómicas que conforman el codo del perro a partir de cortes plastinados ultradelgados.

Visceral Branches of the Abdominal Aorta in the New Zealand Rabbit: Ten Different Patterns

La aorta abdominal del conejo ha sido objeto de estudio e investigacion para desarrollar nuevas plataformas de entrenamiento para protocolos diagnosticos y terapeuticos asi como para probar las virtudes de materiales y equipos endovasculares, sin embargo, existen muy pocas descripciones en la literatura de las ramas viscerales que emergen de la aorta abdominal en esta especie. Las variaciones anatomicas son eventos de ocurrencia comun y por lo tanto deben ser considerados para realizar investigacion y ensayos clinicos. El objetivo del presente estudio ha sido describir los diferentes patrones que pueden presentar las ramas viscerales que emergen de la aorta abdominal en el conejo.