Fx Plata

Effects of rumen-protected methionine on milk production of dairy goats

Abstract Twelve lactating Saanen goats were fed with a total mixed ration (forage:concentrate 67:33) and directly supplemented (administered orally) with 0, 2.5 and 5.0g/head/day of rumen-protected methionine (RPM) for 30d. Body weight was not affected by RPM. There were quadratic (P<0.05) effects on milk yield, fact-corrected milk, energy-corrected milk and milk protein as RPM increased; thus, the highest values of milk yield, fact-corrected milk, energy-corrected milk and milk protein were observed with 2.5g of RPM. Percentage of fat increased quadratically (P<0.05) as RPM doses increased, while fat expressed as grams per day was not affected with RPM. It was possible to improve milk production and milk protein in dairy goats with a daily supplemented dose of 2.5g of RPM. Further studies with more animals should be developed.

Effect of Exogenous Amylase or Glucoamylase Dose on in situ Ruminal Digestion of Corn and Sorghum

Abstract Gutiérrez. C., Mendoza, G.D., Ricalde, R., Melgoza, L.M. and Plata, F. 2005. Effect of exogenous amylase or glucoamylase dose on in situ ruminal digestion of corn and sorghum. J. Appl. Anim. Res., 27: 7–10. Several processes have been developed to increase ruminal digestion of grains. Treatment of grains with exogenous amylase from Bacillus licheniformis and with glucoamylase from Aspergillus niger has increased ruminal digestion. An in situ assay was conducted to determine the effects of the dose of exogenous amylolytic enzymes on in situruminal digestibility (12 h incubation) of corn and sorghum. A complete generalized randomized block design was used, with incubations as blocking criteria. In situ dry matter digestion was increased (P<0.05) with enzyme additions (57.5% control; glucoamylase 75.8%; amylase 82.9%), showing a linear and quadratic effect (P<0.05) of enzyme doses on grain DM digestion. It was concluded that both amylolytic thermostable enzymes have the potential as a feed additive to improve ruminal digestibility of corn and sorghum.

Effect of exogenous glucoamylase enzymes and reduction of grain level on lamb performance

A growth assay was conducted to evaluate if the addition of exogenous glucoamylase enzymes from Aspergillus niger may compensate the reduction of grain level in finishing diets for lambs. Twenty one Suffolk crossbred lambs (BW 16.6±1.5 kg) were randomly assigned to the following treatments: 72% grain; 60% grain + glucoamylase (0.12 g enzyme protein/kg grain) and; 60% grain. The average daily gain (kg), intake (kg/d) and were not affected by the treatments. The best feed conversion was observed with 72% grain; however, partial feed efficiency (slope of regression between intake and average daily gain) was improved in diet with 60% grain plus enzyme.

Influence of Plant Cover on Dietary Selection by Goats in the Mixteca Region of Oaxaca, Mexico

Abstract Franco, F.J., Gómez, G.A., Mendoza, G.D., Bárcena, R., Ricalde, R., Plata, F. and Hernández, J. 2005. Influence of plant cover on dietary selection by goats in the Mixtec Region of Oaxaca, Mexico. J. Appl. Anim. Res., 27: 95–100. This research was conducted to study grazing time and to determine the relationship between the vegetable cover (arboreal, shrubs) and degree of preference by transhumance goats in six rangelands in the Mixteca region of Oaxaca, Mexico. Grazing time and number of bites was recorded by direct observation during summer, autumn and winter. Three preference levels of vegetable cover were established. A total of 65 species were selected: 52% had a frequent consumption coinciding with abundance and 48% were occasionally consumed related to low availability. Shrubs were the main plant preferred (57.2%), followed by forbs (40.5%), whereas, trees were the least preferred (2.2%). A positive relationship was observed between the degree of use and species cover in the rangelands (r=0.703, P<0.001). Plant cover, particularly from trees and shrubs, determines the degree of use by goats in the Mixteca rangelands.

Effect of an Exogenous Glucoamylase during Different Periods of Time on Performance of Lambs Fed Sorghum Based Diets

Abstract Lee-Rangél, H.A., Mendoza, G.D., Pinos-Rodriguez, J.M., Bárcena, R., Plata, F. and Ricalde, R. 2006. Effect of an exogenous glucoamylase during different periods of time on performance of lambs fed sorghum based diets. J. Appl. Anim. Res., 29: 141–144. A growth assay was conducted to evaluate the effects of the addition of an exogenous glucoamylase from Aspergillus niger during different periods of time on lamb performance fed a sorghum-based diet. Fifteen Suffolk crossbred lambs (BW 22+2.5 kg) were randomly assigned to the treatments: control diet, addition of glucoamylase during 50 days, or during the last 15 days of the experiment. The average daily gain (kg) and feed conversion were not affected by the treatments. Results indicate that exogenous glucoamylase did not improve digestibility or lamb performance.

Effects of Bacillus licheniformis Amylase on Starch Digestibility and Sheep Performance

Abstract Crosby, M.M., Mendoza, G.D., Melgoza, L.M., Bárcena, R., Plata, F.X. and Aranda, E.M. 2006. Effects of Bacillus licheniformis amylase on starch digestibility and sheep performance. J. Appl. Anim. Res., 30: 133–136. An experiment was conducted to determine the effects of amylase on starch digestion and sheep performance (45 d) with a sorghum based diet (68%). Thirty-six sheep (Creole x Suffolk, 21.66±6.5 kg BW) were assigned the following doses of amylase from B. licheniformis (g enzyme/kg dry matter of grain): 0.0, 0.6, 1.2, 1.8, 2.4 and 3.0. In vivo digestibility (%) of dry matter was improved (P<0.05) (72.8 vs 81.7%) with amylase. The average daily weight gain (g) and feed conversion were not affected by treatment. Even when dry matter digestibility was increased with amylase from B. licheniformis, sheep performance was not with the exogenous amylolytic enzyme.

The effect of Muhlenbergia macroura dietary level on intake, digestibility and weight changes in volcano rabbit (Romerolagus diazi)

The objective of the study was to evaluate the effect of different levels of Muhlenbergia macroura on feed intake, nutrient digestibility and daily weight changes in volcano rabbits. Thirty-nine-month-old mixed sex rabbits (n=32) were randomly allocated to four dietary levels of M. macroura, i.e. 0, 10, 20 and 30%. Following 14 days of adaptation, daily feed intake (DFI) and daily weight gain (DWG) were recorded and faeces collected during a one-day digestibility trial. Digestibility was estimated with lignin as an internal marker from the feed/faeces ratio. There was no effect (P>0.05) of treatment on DFI. As a daily average, rabbits consumed 26.2 g (SEM 0.20). There were linear (P<0.05) and quadratic (P<0.008) effects between grass levels and DWG. Weights were negatively affected as grass dietary levels increased. Mean DWG values were +1.5,−1.0,−2.1,−0.5 g/day for 0, 10, 20 and 30%, respectively (SEM 0.14). There was a quadratic response on digestibility of dry matter (DM) (P<0.04) and neutral detergent fibre (NDF) (P<0.02). Digestibility of DM for grass levels was 59.9, 67.6, 64.5, 62.3% (SEM 1.14) whereas digestibility mean values for NDF were 26.2, 39.3, 33.6 and 24.6%, respectively (SEM 2.26). Digestibility for organic matter, crude protein, ether extract, acid detergent fibre, ash and digestible energy was not affected (P>0.05) by grass levels. Daily requirement of digestible energy for maintenance in volcano rabbits was estimated at 178.1 kcal/kg WB0.75. Increasing dietary levels of M. macroura impairs DWG, even when DM and NDF digestibility showed a quadratic increase response.

Defecation rate in Romerolagus diazi fed with different levels of Muhlenbergia macroura

Defecation rate is important to estimate wildlife populations based on pellet-counts procedures. An experiment utilising volcano rabbit (Romerolagus diazi) was conducted to evaluate the number of pellets produced per rabbit per day and its correlation with weight of the excreta, when they were fed with different levels of Muhlenbergia macroura (0, 10, 20, and 30%). Thirty individuals (538.25±23.47 g BW) were randomly distributed in four diets; the average numbers of faecal pellets dropped per rabbit in 24 h were measured during eight days. A total of 69,955 faecal pellets were collected, with a defecation rate of 253.46±4.07 pellets/rabbit/day and an average weight of 10.39±3.99 g. There was a high correlation between defecation rate and weight (R 2=0.76, p<0.0001). No changes were found (p>0.10) in defecation rate by M. macroura levels in the diet. For this reason, this index can be used to estimate R. diazi population in the wildlife.

Effect of exogenous fibrolytic enzyme and slow release urea in finishing rations for lambs

An experiment was conducted to evaluate if the combination of fibrolytic enzymes (FEs) and slow release urea (SRU) could improve the productive performance of lambs fed with a diet of 60% of concentrate. Twenty lambs were assigned to a completely randomized design with factorial arrangement (2×2). The treatments were a control group, SRU diet (1% DM), FE (0.3% DM) and the combination of both additives (SRU+FE). No interaction was detected between SRU and FE. The SRU significantly reduced the daily gain (0.14 vs. 0.20 kg/d; P < 0.01) and negatively affected the food conversion (P< 0.01; 8.24 vs. 5.99). The addition of the FE had no effect on the productive parameters or indicators of rumen fermentation. The results indicate that slow release urea can negatively affect finishing rations, and that there is no response to the addition of FEs in these conditions.

Comparación de métodos basados en los requerimientos nutricionales y disponibilidad de biomasa para estimar la capacidad de carga para venado cola blanca

Due to the importance of the estimation of carrying capacity (K animals/ha) in white tailed deer, the objectives of this study were: 1) To compare the estima...