Martín F. Montaño-Gómez

Effect of Duration of Zilpaterol Hydrochloride Treatment on Carcass Characteristics and Weight Gain in Grazing Pelibuey Lambs

Abstract Salinas-Chavira, J., Domínguez-Muñoz, M., Díaz-Martínez, R., Cruz-Bautista, P., Montaño-Gómez, M.F. and Arzola-Alvarez, C. 2006. Effect of duration of zilpaterol hydrochloride treatment on carcass characteristics and weight gain in grazing Pelibuey lambs. J. Appl. Anim. Res., 29: 25–28. The effect of zilpaterol hydrochloride (ZH) supplementation on carcass characteristics and weight gain were studied in grazing Pelibuey lambs. Thirty-six intact male Pelibuey sheep, (21.42±3.32 kg) were kept in three paddocks with Angleton grass (Dichantium aristatum) and were fed a supplement (sorghum, soybean meal, urea, molasses, tallow and minerals) containing 21.76% crude protein and 2.77 Meal I kg ME during 60 days feeding trial. Three paddocks formed the corresponding experimental groups: T1 (control), with no ZH in the supplement; T2 received 10 ppm ZH in supplement during the last 20 days of the trial and T3 received ZH during the last 30 days. The backfat was thinner (P<0.05) in both ZH groups than in the control group, measuring 0.28, 0.24 and 0.24 cm in T1, T2 and T3, respectively. The Longissimus dorsi measured 6.53, 6.24 and 5.84 cm2, respectively, and did not differ among dietary treatments. The average daily gain was also similar (P>0.05) among all experimental groups. It may be concluded that supplementation of zilpaterol hydrochloride during different intervals reduced the backfat cover in grazing Pelibuey sheep fed on supplemental concentrate.

Influence of Feeding Enzymatically Hydrolyzed Yeast Cell Wall on Growth Performance and Digestive Function of Feedlot Cattle during Periods of Elevated Ambient Temperature.

In experiment 1, eighty crossbred steers (239±15 kg) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers (292±5 kg) with cannulas in the rumen and proximal duodenum were used in a 4×4 Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets.

Effect of Tallow and Rice Polishings in Feedlot Rations on Growth and Carcass Characteristics of Lambs

Abstract Salinas-Chavira, J., Guerrero, V.I., Robles, C.A., Montaño-Gómez, M.F. and Montañez-Valdez, O.D. 2008. Effect of tallow and rice polishings in feedlot rations on growth and carcass characteristics of lambs. J. Appl. Anim. Res., 34: 45–48. Effect of tallow (Ta) level in rations with rice polishings (RP) on growth and carcass characteristics was studied on twenty one intact males (22.76±3.11kg, Dorper? Pelibuey) housed in individual pens and assigned at random to 3 treatments viz. 0, 2.5 or 5% tallow (ta) replacing equal quantities of sorghum grain and 18% rice polish (RP). Lambs were fed for 60 d on diets formulated to contain 14% CP and 2.6 Meal I kg ME. No differences (P>0.05) were observed among treatments for daily dry matter intake, daily weight gain, feed efficiency, subcutaneous fat and Longissimus dorsi area. It is concluded that rations for feedlot lambs with 18% of rice polishings may include 5% of tallow, without negative effects on growth or carcass of lambs.

Effect of Ionophore Supplementation and Trenbolone Implant on Growth and Carcass Characteristics of Lambs

Abstract Salinas-Chavira, J., García-Barrera, L. A., Cruz-Bautista, H., Montaño-Gómez, M. F. and Calderón-Cortés, J. F. 2005. Effect of ionophore supplementation and trenbolone implant on growth and carcass characteristics of lambs. J. Appl. Anim. Res., 28: 49–52. To study the effect of ionophore (monensin) and trenbolone implant on feedlot lamb growth performance (60 d) and carcass characteristics, 18 intact males (Pelibuey × Dorper 19.9±2.25 kg) were housed in individual pens and assigned to 3 treatments viz. Tl: no additive nor implant (control), T2: basal diet (14% CP and 2.6 Mcal/kg ME) with ionophore (25 ppm sodium monensin) supplementation and T3: T2 plus implant (35 mg of trenbolone acetate + 5 mg of 17-β estradiol). No differences (P>0.05) were found among treatments for daily dry matter intake, daily weight gain, feed efficiency and subcutaneous fat. Longissimus dorsi area was similar in T2 and T3 (P>0.05) but higher than that in Tl (P<0.05). Ionophore alone or with implant did not improve feedlot lamb performance (P<0.05) or subcutaneous fat, but had beneficial effect on Longissimus dorsi area. Implant in addition to ionophore did not cause any further improvement.

Influence of mixing supplements (dry or liquid) with monensin or soluble protein on the feeding value of finishing diets for feedlot cattle

ABSTRACT The influence of supplement form (dry vs. liquid) on the feeding value of diets for feedlot cattle was evaluated. Treatments were: (1) dry supplement (DS); (2) liquid supplement (LS, all supplemental macro- and micro-minerals, salt, monensin and urea provided as a uniform blend with cane molasses; (3) LS minus monensin, that was provided in a 3% premix with dried distillers grains plus solubles before combination into a complete mixed diet (LS-MON) and (4) LS, except that condensed molasses solubles replaced 41% (DM basis) of the cane molasses solids (LSUF). In a 112-day trial involving 160 Holstein steers (473 ± 32 kg) cattle fed DS, LS, LS-MON and LSUF diets had similar (P > .10) ADG, DMI, feed efficiency and estimated dietary NE. The effects on characteristics of digestion were evaluate using four Holstein steers with cannulas in rumen and proximal duodenum. There were no treatment effects (P > .10) on ruminal digestion of OM, and feed N, microbial efficiency and ruminal N efficiency. It is concluded that the form of incorporation of minor dietary ingredients during batch mixing (dry premix or in combination with a liquid carrier) will not appreciably affect the feeding value of growing-finishing diets for feedlot cattle.

Influence of dietary cation–anion difference in finishing diets fed to Holstein steers during periods of high ambient temperature on feedlot performance and digestive function

ABSTRACT One hundred twenty-six Holstein steers (457.1 ± 27.5 kg BW) were used in a 127-d experiment to evaluate the influence of dietary cation–anion difference (DCAD) on growth performance and carcass characteristics. Treatments consisted of steam-flaked corn-based diets supplemented to provide DCAD of 34, 84 or 134 mEq/kg diet DM. There was no treatment effect (P > .20) on ADG, DMI, gain efficiency or dietary NE. Six Holstein steers (196 ± 3 kg) with cannulas in rumen and proximal duodenum were used in a replicated 3 × 3 Latin Square design to evaluated treatment effects on digestion characteristics. The DCAD did not affect (P > .20) ruminal or total digestion of OM, NDF, starch and N, or ruminal pH and VFA molar proportions. It is concluded that increasing DCAD of Holstein steers fed a conventional steam-flaked corn-based diet under conditions of high ambient temperature will not enhance growth performance.

Genome-Wide SNP Signal Intensity Scanning Revealed Genes Differentiating Cows with Ovarian Pathologies from Healthy Cows

Hypoplasia and ovarian cysts are the most common ovarian pathologies in cattle. In this genome-wide study we analyzed the signal intensity of 648,315 Single Nucleotide Polymorphisms (SNPs) and identified 1338 genes differentiating cows with ovarian pathologies from healthy cows. The sample consisted of six cows presenting an ovarian pathology and six healthy cows. SNP signal intensities were measured with a genotyping process using the Axiom Genome-Wide BOS 1 SNPchip. Statistical tests for equality of variance and mean were applied to SNP intensities, and significance p-values were obtained. A Benjamini-Hochberg multiple testing correction reveled significant SNPs. Corresponding genes were identified using the Bovine Genome UMD 3.1 annotation. Principal Components Analysis (PCA) confirmed differentiation. An analysis of Copy Number Variations (CNVs), obtained from signal intensities, revealed no evidence of association between ovarian pathologies and CNVs. In addition, a haplotype frequency analysis showed no association with ovarian pathologies. Results show that SNP signal intensity, which captures not only information for base-pair genotypes elucidation, but the amount of fluorescence nucleotide synthetization produced in an enzymatic reaction, is a rich source of information that, by itself or in combination with base-pair genotypes, might be used to implement differentiation, prediction and diagnostic procedures, increasing the scope of applications for Genotyping Microarrays.

Pathophysiological response to experimental oral overdose of different forms of selenium in lambs

Abstract Twelve male lambs (30.5±2.1 kg) with cannulas in the rumen were divided into three groups to evaluate the accidental toxicity of selenium (Se) via digestive tract. The first group received intraruminal bolus without a Se source; the second group received intraruminal bolus with sodium selenite (SS: Na2SeO3); the third group received intraruminal bolus with barium selenate (BS: BaSeO4). The ruminal boluses were immediately degraded by a manufacturing defect, releasing an amount of 366 mg Se via rumen. All lambs had tachypnea (80 cycles per minute), a metallic smell in the oral cavity and laminitis foot. Analyses of necropsy and histopathology showed frequencies of lesions in the myocardium and skeletal muscle, lesions in the myocardium were more common in lambs intoxicated with SS or BS than the control group (P<0.05); the tissues were swollen and there were hyaline fibres (Zenker degeneration), as well as fragments and proliferation of the nuclei with necrosis. Se concentration in lambs intoxicated with SS and BS were: myocardium: 0.389 and 0.332; skeletal muscle: 0.583 and 0.492; and kidney: 2.871 and 2.841 μg/g fresh tissue, respectively. The Se concentration in blood increased over 2.5 times in the intoxicated lambs with both sources of Se (0.14 vs. 0.36 μg/mL) from baseline to the 22 days of sampling. There was a lower correlation (r=0.46) in SS intoxication group than the control and BS group (r≥0.93). As a conclusion, high dosages of 366 mg Se or 12 mg Se/kg BW in an accidental dosage did not cause a severe mortality but all lambs immediately showed reduced feed intake, metallic smell exhalation and depression.