Influence of methionine supplementation of growing diets enriched with lysine on feedlot performance and characteristics of digestion in Holstein steer calves.

ObjectiveTwo trials were conducted in order to examine the effects of level of supplemental methionine on productive performance, dietary energetic, plasma amino acid concentration, and digestive function.MethodsDietary treatments consisted of a steam-flaked corn-based diet containing urea as the only source of supplemental nitrogen supplemented with no supplemental amino acid (control), or control plus 1.01% lysine and 0.032%, 0.064%, 0.096%, or 0.128% methionine. In Trial 1, 150 Holstein steer calves (127±4.9 kg) were utilized to evaluate the influence of treatments on growth-performance, dietary energetic, plasma amino acid concentration during the first 112 days of growing period. During the initial 56-d period calves received the 5 experimental diets. During the subsequent 56-d period all calves were fed the control diet.ResultsDuring the initial 56-d period, methionine supplementation increased (linear effect, p<0.01) plasma methionine. In the presence of supplemental lysine, increases on level of methionine in diet did not affect average daily gain. However, increased gain efficiency (quadratic effect, p = 0.03) and estimated dietary net energy (NE; linear effect, p = 0.05). Estimated metabolizable methionine supply was closely associated (R2 = 0.95) with efficiency NE utilization for maintenance and gain. During the subsequent 56-d period, when all calves received the control diet (no amino acid supplementation), plasma amino acid concentrations and growth performance was not different among groups. However, the effects of methionine supplementation during the initial 56-period carried over, so that following a 56-d withdrawal of supplementation, the overall 112-d effects on gain efficiency (quadratic effect, p = 0.05) dietary NE (linear effect, p≤0.05) remained appreciable. In Trial 2, 5 cannulated Holstein steers were used to evaluate treatment effects on characteristics of digestion and amino acid supply to the small intestine. There were no treatment effects on flow of dietary and microbial N to the small intestine. Postruminal N digestion increased (p = 0.04) with increasing level of supplemental methionine. Methionine supplementation linearly increased (p<0.01) duodenal flow of methionine. Likewise, lysine supplementation increased an average of 4.6% (p = 0.04) duodenal flow of lysine. In steers that received non-supplemented diet, observed intestinal amino acid supply were in good agreement with expected.ConclusionWe conclude that addition of rumen-protected methionine and lysine to diets may enhance gain efficiency and dietary energetics of growing Holstein calves. Observed amino acid supply to the small intestine were in good agreement with expected, supportive of NRC (2000, Level 1)

Influence of Kaolinite Clay Supplementation on Growth Performance and Digestive Function in Finishing Calf-fed Holstein Steers.

Two experiments were conducted to examine the influence of kaolinite clay supplementation (0%, 1%, or 2% diet dry matter [DM] basis) on characteristics of digestion (Trial 1) and growth performance (Trial 2) in calf-fed Holstein steers fed a finishing diet. In Trial 1, 6 Holstein steers (539±15 kg) with ruminal and duodenal cannulas were used to evaluate treatment effects on characteristics of digestion. Kaolinite clay supplementation decreased total tract DM digestion (linear effect, p<0.01) without effects (p≥0.10) on site and extent of digestion of organic matter, neutral detergent fiber, starch and N, or ruminal microbial efficiency. There were no treatment effects on ruminal pH, volatile fatty acids molar proportions or estimated methane production. In Trial 2, 108 Holstein steers (132.4±5.6 kg) were used in a 308-d study to evaluate growth performance and carcass characteristics. There were no treatment effects (p>0.10) on average daily gain (ADG) and gain efficiency (ADG/dry matter intake). Kaolinite supplementation tended (linear effect, p = 0.08) to increase dietary net energy (NE) during the initial 112-d period. However, the overall (308-d) effect of supplementation dietary NE was not appreciable (p>0.20). However, due to the inertness of kaolinite, itself, the ratio of observed-to-expected dietary NE increased with kaolinite supplementation. This effect was more pronounced (linear effect, p 0.03) during the initial 224 d of the study. Overall (308 d), kaolinite supplementation tended to increase (linear effect, p = 0.07) dietary NE by 3% over expected. Kaolinite supplementation did not affect carcass weight, yield grade, longissimus area, kidney, pelvic and heart fat, and quality grade, but decreased (linear effect, p = 0.01) dressing percentage. It is concluded that kaolinite supplementation up to 2% of diet DM may enhance energetic efficiency of calf-fed Holstein steers in a manner independent of changes in characteristics of ruminal and total tract digestion

Influence of ruminal degradable intake protein restriction on characteristics of digestion and growth performance of feedlot cattle during the late finishing phase.

Two trials were conducted to evaluate the influence of supplemental urea withdrawal on characteristics of digestion (Trial 1) and growth performance (Trial 2) of feedlot cattle during the last 40 days on feed. Treatments consisted of a steam-flaked corn-based finishing diet supplemented with urea to provide urea fermentation potential (UFP) of 0, 0.6, and 1.2%. In Trial 1, six Holstein steers (160 ± 10 kg) with cannulas in the rumen and proximal duodenum were used in a replicated 3 × 3 Latin square experiment. Decreasing supplemental urea decreased (linear effect, P ≤ 0.05) ruminal OM digestion. This effect was mediated by decreases (linear effect, P ≤ 0.05) in ruminal digestibility of NDF and N. Passage of non-ammonia and microbial N (MN) to the small intestine decreased (linear effect, P = 0.04) with decreasing dietary urea level. Total tract digestion of OM (linear effect, P = 0.06), NDF (linear effect, P = 0.07), N (linear effect, P = 0.04) and dietary DE (linear effect, P = 0.05) decreased with decreasing urea level. Treatment effects on total tract starch digestion, although numerically small, likewise tended (linear effect, P = 0.11) to decrease with decreasing urea level. Decreased fiber digestion accounted for 51% of the variation in OM digestion. Ruminal pH was not affected by treatments averaging 5.82. Decreasing urea level decreased (linear effect, P ≤ 0.05) ruminal N-NH and blood urea nitrogen. In Trial 2, 90 crossbred steers (468 kg ± 8), were used in a 40 d feeding trial (5 steers/pen, 6 pens/ treatment) to evaluate treatment effects on final-phase growth performance. Decreasing urea level did not affect DMI, but decreased (linear effect, P ≤ 0.03) ADG, gain efficiency, and dietary NE. It is concluded that in addition to effects on metabolizable amino acid flow to the small intestine, depriving cattle of otherwise ruminally degradable N (RDP) during the late finishing phase may negatively impact site and extent of digestion of OM, depressing ADG, gain efficiency, and dietary NE

Influence of dietary nonstructural carbohydrate concentration on growth performance and carcass characteristics of Holstein steers

Objective Since very little information exists about the topic; in this experiment we compare, in a long-term finishing program, the growth-performance responses and carcass characteristics of Holstein steers where non-structural carbohydrate concentration of the diet is reduced from 64% to 51% (dry matter basis). Methods Sixty Holstein steer calves (129±2.2 kg) were blocked by initial weight into five groups and randomly assigned within weight groupings to 10 pens. Calves were fed with a steam-flaked corn-based finishing diets containing 51% higher fiber (HF) or 64% lower fiber (LF) nonstructural carbohydrates. Non-structural carbohydrates concentrations were manipulated substituting dried distiller grain with solubles and alfalfa hay for flaked corn. Cattle were weighed every 112 days and at the end of the experiment (day 308) when the cattle were harvested and carcass characteristics were evaluated. Results Steers fed the HF diet showed improvement (8.8%) in average daily gain (ADG) during the initial 112-d period. This effect was followed by a numerical trend for greater ADG throughout the remainder of the study so that overall ADG tended to be greater (4.9%, p = 0.06) for the HF than for LF. There were no treatment effects on dry matter intake. Gain efficiency and estimated dietary net energy (NE) were greater 8.3% and 5.2%, respectively for HF during the initial 112-d period. Overall (308-d) gain efficiency and estimated dietary NE were similar for both dietary treatments. However, due to differences in tabular dietary NE, the ratio of observed:expected dietary NE tended to be greater (4.1%, p = 0.06) for the HF vs LF diet. There were no treatment effects on carcass characteristics except for a tendency toward a slightly greater (0.5%, p = 0.09) estimated carcass yield. Conclusion Reducing the non-structural carbohydrate concentration of a conventional steam-flaked corn-based growing finishing diet for Holstein steers can effectively enhance growth performance, particularly during the early growing and late finishing phases

Influence of environmental factors on surface activity of \u3cem\u3eParuroctonus marksi\u3c/em\u3e (Scorpiones: Vaejovidae) in the Mojave Desert

Many environmental factors may influence the activity pattern of scorpions in arid ecosystems. We investigated the seasonal variations of Paruroctonus marksi scorpion activity in the Mojave Desert (California, USA). Black light surveys were carried out within two 100 ×100 m plots from August 2017 to September 2018. The majority (85%) of scorpions were found in open areas compared with being in vegetation. The presence of P. marksi was positively correlated with both water vapor pressure and soil temperature, while moon illumination had no significant effect on P. marksi foraging behavior. Scorpions might be using humidity as an indicator of prey abundance and since they are not visual hunters, and moonlight does not affect their surface activity possibly due to lack of visual hunters in the study site

Energy value of unfermented dried grape pomace as substitute of alfalfa hay in diets for growing lambs

The energy value of unfermented dried grape pomace (DGP) was evaluated in an 84 d feeding trial on 16 Pelibuey×Dorper lambs (17.8 ± 2.0 kg). The control diet contained 90% mature alfalfa hay and 10% concentrates. Treatments consisted in the replacement (DM basis) of alfalfa hay by DGP at 0, 10, 20 or 30%. Lambs were blocked by weight and assigned individually to pens. Increasing DGP level in diet tended (P=0.06) to decrease daily gain and linearly increased (P=0.04) dry matter intake (DMI); thus, feed efficiency, dietary energy, and observed-to-expected diet NE were linearly decreased (P<0.01), increasing linearly (P<0.01) observed-to-expected DMI coefficient as DGP level was increased in the diet. There were no effects of treatments on carcass characteristics. Using the replacement technique, the energy value of DGP were 0.80, 0.75 and 0.67 Mcal ENm/kg DM, for 10, 20 and 30% of inclusion, respectively. It is concluded that the estimated NE of DGP at 10% inclusion level in the diet is very similar to the NE value assigned by the NRC (2007) for the fermented DGP. Increasing the inclusion of DGP levels beyond 10% decreases its energy value, maybe due to the negative associative effects of chemical compounds (such as phenols) naturally contained in DGP

Influence of tannins supplementation on growth performance, dietary net energy and carcass characteristics of yearling steers fed finishing diet containing dried distillers grains with solubles

Finishing diets containing 15% DDGS with 0, 0.22, and 0.44% condensed tannin did not affect average daily gain, but linearly increased dry matter intake. Tannin supplementation linearly decreased gain efficiency, and estimated dietary NE. Carcass characteristics were not affected by tannin supplementation. Therefore, tannins supplementation did not enhance growth performance of yearling steers fed a high-energy finishing diet containing 15% DDGS, and may decrease efficiency of energy utilization

Productive and reproductive performance and metabolic profiles of ewes supplemented with hydroponically grown green wheat (Triticum aestivum L.)

Inclusion of high levels of concentrate in the diets of late gestation and lactating ewes to improve productive and reproductive performance is a common practice. However cost-effective alternate feeding strategies for small ruminants must be developed and evaluated in order to counteract sustainability issues of feeding them concentrate feeds (Alexandre and Mandonnet, 2005). Hydroponically grown green forages are a potential high feed quality feedstuff in arid and semiarid regions of the world (Al-Faraki and Al-Hashimi, 2012). The nutritive value and fermentative characteristics of hydroponically grown forages positively influenced the performance of late gestation and lactating ewes (Herrera et al., 2010; Gebremedhin, 2015). Earlier investigations emphasized effects of dietary quality on endocrine and metabolic profiles in ewes during pregnancy and lactation (Lemley et al., 2014; Vonnahme et al., 2013). However adequate nutritional status of ewes is associated with favorable productive and reproductive performance whereby blood glucose, non-esterified fatty acids (NEFA) and blood urea nitrogen (BUN) are utilized to sustain a desirable protein and energy balance in ewes during gestation and lactation (Hatfield et al., 1999). Changes in metabolic hormones, such as insulin, play an important role in metabolic adaptation to changes in body weight (BW) and body condition while providing diagnostic information to evaluate ewe nutritional status (Caldeira et al., 2007). Cortisol may be particularly important in this regard as it is the predominant glucocorticoid in sheep blood and has been used as a reliable physiological endpoint to determine ewe responses to a variety of physiological, physical and environmental stress (Moolchandani et al., 2008). A paucity of information is available with respect to the metabolic profile and performance during mating, gestation and lactation of ewes fed diets containing hydroponically grown green wheat (HGW). Thus this experiment was conducted to determine effects of replacement of dry-rolled corn (DRC) and cottonseed meal (CSM) by HGW in an oat hay-based diet on the metabolic profile as well as the productive and reproductive performance of Katahdin female lambs.Twenty six Katahdin ewes (i.e., female lambs from breeding to 2 mo of their 1st lactation) were used in a completely randomized design (13/treatment)to evaluate effects of replacement of dietary dry-rolled corn grain (DRC) and cottonseed meal(CSM) with hydroponically grown whole plant green wheat (HGW; Triticum aestivum L.) on productive parameters and blood metabolites during mating, gestation and lactation, and on body weight (BW) gain of their lambs in their 1st 60 days of age. The gestation diet contained 70% oat hay, 20% rolled corn grain and 10% cottonseed meal, while the lactation diet contained 50% oat hay, 20% DRC and 30% CSM. Treatments consisted of total replacement of DRC and CSM with HGW in the gestation diet, while in the lactation diet HGW replaced 100% of the DRC and 33% of the CSM. There were no diet effects on reproductive parameters, and substitution of DRC and CSM with HGW did not affect dry matter intake during gestation and lactation. The BW gain of the lambs that were fed HGW did not differ from controls in the first 2 months of gestation, while it was lower (P < 0.05) at the last 3 months of gestation. Feeding HGW did not affect birth BW of lambs or subsequent BW gains through 60 days of age. Plasma non-esterified fatty acids (NEFA) were not affected by the diets fed during gestation, but were 56% lower (P < 0.05) at day 60 of lactation. Plasma glucose was only lower (P < 0.05) at day 90 of gestation, and blood urea nitrogen was only lower (P < 0.05) at day 30 of lactation. There were no effects of diets on plasma insulin, cortisol or progesterone during gestation and lactation. Hydroponically grown green wheat is a suitable substitute for a portion of the DRC and CSM in ewes diets during gestation and lactation without negative effects

Estimación del tiempo de mezclado en un modelo de acrílico de un convertidor Peirce-Smith

La distribución de tiempos de residencia (RTD) es un modelo estadístico que determina para un elemento diferencial de un fluido, el tiempo que este permanece dentro de un recipiente con o sin reacción; los datos obtenidos mediante esta técnica permite mejorar el diseño de reactores químicos, puesto que determina la magnitud de zonas muertas en las que la hidrodinámica en el reactor no permite el desarrollo de reacciones; además permite estimar la eficiencia de las reacciones involucradas. En este trabajo se presenta la estimación de tiempos de mezclado en un modelo de un convertidor metalúrgico de Cobre utilizando la RTD y un trazador químico.The residence time distribution (RTD) function is a statistical model used to estimate the actual residence time of fluid differential elements in reactors and vessels. By using the RTD function it is possible to improve reactor design and to estimate up to what extent the hydrodynamics within the vessel would render the efficiency of those sought after reactions. This work presents the estimation of mixing times using a plexiglass model of a copper converter and a chemical tracer