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31.
Yancey EJ Dikeman ME Addist PB Katsanidis E Pullen M 《Journal of animal science》2002,80(7):1904-1910
32.
Estimates of heritabilities and genetic correlations were obtained for weaning weight records of 23,681 crossbred steers and heifers and carcass records from 4,094 crossbred steers using animal models. Carcass traits included hot carcass weight; retail product percentage; fat percentage; bone percentage; ribeye area; adjusted fat thickness; marbling score, Warner-Bratzler shear force and kidney, pelvic and heart fat percentage. Weaning weight was modeled with fixed effects of age of dam, sex, breed combination, and birth year, with calendar birth day as a covariate and random direct and maternal genetic and maternal permanent environmental effects. The models for carcass traits included fixed effects of age of dam, line, and birth year, with covariates for weaning and slaughter ages and random direct and maternal effects. Direct and maternal heritabilities for weaning weight were 0.4 +/- 0.02 and 0.19 +/- 0.02, respectively. The estimate of direct-maternal genetic correlation for weaning weight was negative (-0.18 +/- 0.08). Heritabilities for carcass traits of steers were moderate to high (0.34 to 0.60). Estimates of genetic correlations between direct genetic effects for weaning weight and carcass traits were small except with hot carcass weight (0.70), ribeye area (0.29), and adjusted fat thickness (0.26). The largest estimates of genetic correlations between maternal genetic effects for weaning weight and direct genetic effects for carcass traits were found for hot carcass weight (0.61), retail product percentage (-0.33), fat percentage (0.33), ribeye area (0.29), marbling score (0.28) and adjusted fat thickness (0.25), indicating that maternal effects for weaning weight may be correlated with genotype for propensity to fatten in steers. 相似文献
33.
This research explores the relationship between generally accepted and alternative cattle age-prediction methods and chronological age. Cattle (n = 386) of documented ages ranging from 370 to 1,115 d of age were used. Dentition (DEN), USDA maturity score (MS), lens weight (LW), and lens total N (LN) content were used as possible predictors of age. Correlations with age were determined: LW (r = 0.77); DEN (r = 0.74); LN (r = 0.71); and MS (r = 0.64). Stepwise backward regression was used to generate an age prediction equation: Age (mo) = -21.79 + 17.23(LW, g) + 0.038(DEN). By this equation, 38% of cattle = 20 mo of age were verified as = 20 mo of age. Independent measures verified the following percentages of cattle as = 20 mo of age: LW (20.2%), MS (11.0%), DEN (9.6%), and LN (8.7%). The DEN verified that 87.6% were verified as <30 mo old, and LW verified 81.6% of cattle as <30 mo old. A separate group of cattle (n = 18) ranging in age from 1 to 12 yr were evaluated for lens properties, for which LW (R(2) = 0.91) and LN (R(2) = 0.92) were highly correlated with age. The LW and DEN were the best predictors of age for cattle 13- to 37-mo-old and yielded the most accurate age prediction when used in combination (R(2) = 0.67). 相似文献
34.
Stephens JW Dikeman ME Unruh JA Haub MD Tokach MD Dritz SS 《Journal of animal science》2008,86(7):1669-1677
The objective of this study was to determine the effects of oral administration of sodium citrate (CIT) or acetate (ACE) to pigs on blood parameters, postmortem glycolysis, pH decline, and quality attributes of pork. Previous studies have shown that CIT has the potential to inhibit phosphofructokinase (PFK), a key enzyme in postmortem muscle glycolysis. In Exp. 1, CIT, ACE, or water was orally administered (0.75 g/kg of BW) to 24 pigs. After a 30-min rest, pigs were exercised, and blood samples were taken at 45 and 75 min after oral treatment. Citrate and ACE tended (P = 0.08) to increase blood pH and increased (P = 0.02) bicarbonate levels immediately after exercise. After a 30-min rest, blood pH of pigs administered ACE tended (P = 0.09) to remain higher, whereas blood pH of CIT-treated pigs was similar to that of control pigs. Bicarbonate levels in ACE- and CIT-treated pigs were still greater (P < 0.05) than those of control pigs at 75 min after oral treatment. In Exp. 2, 30 pigs were administered CIT, ACE, or water 45 min before stunning (electric plus captive bolt). Antemortem treatments had no effect (P > 0.10) on muscle pH or postmortem concentrations of the glycolytic metabolites of glucose-6 phosphate, fructose-6 phosphate, fructose-1,6 bisphosphate, glyceraldehyde-3 phosphate, dihydroxyacetone phosphate, or lactate. Minor, but inconsistent, differences in quality attributes were found in LM chops, and no differences in quality attributes were found between control and CIT- or ACE-treated pigs for inside and outside semimembranosus muscles (P > 0.10). There was no significant inhibition of the PFK enzyme by orally administered CIT or ACE; however, the PFK glycolytic metabolite data analysis indicated that PFK was a main regulatory enzyme in postmortem muscle. 相似文献
35.
The aim of this study was to investigate whether the skim milk progesterone concentrations at artificial insemination (AI) and day of rise of post-ovulatory progesterone concentration thereafter affect the conception and embryonic death rates in repeat-breeding cows. Milk samples were obtained from 96 repeat-breeding cows that failed to conceive to three or more AIs. The samples were taken from the cows at the day of AI and three times/week until day 45 post-AI. Skim milk was obtained after centrifugation and used for progesterone assay. The cows with a progesterone concentration more than 0.5 ng/ml at AI showed a significantly higher incidence of late embryonic death than those having a progesterone concentration<0.5 ng/ml at AI (p<0.01). As the progesterone level at insemination rose, conception rate declined. A negative correlation was shown between conception rate and skim milk progesterone level at AI. Of 56 cows showing a rise of progesterone to 1 ng/ml or more within 6 days after AI, 28 cows (50%) conceived. On the contrary, only eight of 39 cows (20.5%) conceived when the progesterone rose up to 1 ng/ml after day 6 post-AI. We concluded that increased progesterone concentration at the time of AI and delayed rise of progesterone post-AI might lead to decrease in fertility in repeat-breeding cows. 相似文献
36.
A Ortega-Pacheco JC Rodríguez-Buenfil JC Segura-Correa ME Bolio-Gonzalez M Jiménez-Coello C Linde Forsberg 《Reproduction in domestic animals》2006,41(5):429-437
The objective of this study was to estimate the prevalence of and risk factors for pathological conditions of the reproductive organs in stray dogs under tropical conditions. Three hundred and eighteen dogs were examined post-mortem in the period from 1 July 2002 to 30 June 2003. Before killing, a blood sample (from the cephalic vein) for testosterone assay was taken. Pathological conditions of the reproductive organs were found in 135 of the dogs (42.5%) and in 175 of the testes (64.8%). The most frequent pathologies found were testicular degeneration, cryptorchidism, testicular hypoplasia and testicular tumours (in 15.1%, 6.6%, 6.6% and 5.4% of the dogs and 15.1, 4.6, 6.0 and 3.5 of the testes, respectively). Transmissible venereal tumour (TVT) was seen in 5.4% of the dogs. Testicular degeneration was more common in old dogs and underweight dogs (p < 0.05). Testicular tumours were 14.3 times more common in cryptorchid dogs. Age was another important factor for the development of testicular tumours (p < 0.05). Lower levels of testosterone concentration (p < 0.05) were observed in dogs with advanced testicular degeneration (0.7 +/- 0.8 nM), dogs with hypoplastic testicles (0.8 +/- 0.9 nM) and dogs with one degenerated and one retained testis or with bilateral cryptorchidism (1.2 +/- 0.9 nM) compared to dogs with one or two normal testes (7.0 +/- 5.5 nM). Testicular volume and weight were significantly lower in degenerated, hypoplastic and retained testes compared with the contralateral normal testis. Some spermatogenic activity was found in three of the retained testes, producing oligozoospermic smears with a high percentage of sperm abnormalities. No comparable epidemiological data about male pathological conditions of the reproductive organs in the dog is available. The prevalence found in this study, yet, appears high. 相似文献
37.
Hot carcasses from 220 steers (progeny of Hereford or Angus dams mated to Angus, Charolais, Galloway, Gelbvieh, Hereford, Longhorn, Nellore, Piedmontese, Pinzgauer, Salers, or Shorthorn sires) were used to develop equations to estimate weights and percentages of retail product (RP) and trimmable fat (TF) yields. Independent variables examined were 1) 12-13th rib fat probe (12RFD), 2) 10-11th rib fat probe (10RFD), 3) external fat score (EFS), 4) percentage of internal fat estimated hot (H%KPH), 5) hindquarter muscling score (HQMS), and 6) hot carcass weight (HCW). Right sides of the carcasses were fabricated into boneless retail cuts, trimmed to .76 cm of subcutaneous and visible intermuscular fat, and weighed. Cuts were trimmed to 0 cm of subcutaneous and visible intermuscular fat and reweighed. Multiple linear regression equations containing 12RFD, EFS, H%KPH, and HCW accounted for 95 and 89% of the variation in weight of total RP at .76 and 0 cm of fat trim, respectively. When weights of RP from the four primal cuts (.76 and 0 cm of fat trim) were the dependent variables, equations consisting of 12RFD, EFS, H%KPH, and HCW accounted for 93 to 84% of the variation. Hot carcass equations accounted for 83% of the variation in weight of total TF at both .76 and 0 cm of fat trim. Furthermore, equations from hot carcass data accounted for 54 and 51% of the variation in percentage of total RP and 57 and 50% of the variation in percentage of RP from the four primal cuts at .76 and 0 cm of fat trim, respectively. Hot carcass prediction equations accounted for 72% of the variation in percentage of total TF at both fat trim levels. Hot carcass equations were equivalent or superior to equations formulated from chilled carcass traits. 相似文献
38.
聚丙烯酰胺防治坡地水土流失田间试验研究 总被引:14,自引:1,他引:13
坡地篱用聚丙烯酰胺可以减少地表径流,提高土壤含水量,促进土壤沉降,增强土壤结构性和水稳性,因而提高了土壤的持水性和抗蚀性,减少了土壤侵蚀量和肥力流失量,有利于作物增产。施用聚丙烯酰胺可使产量增加18.7%~32.4%。施用聚丙烯酰胺对环境无不良影响,而且投入费用较低,是一条值得探索的防治坡地水土流失的新途径。 相似文献
39.
LA Gracia‐Calvo LJ Ezquerra M Martín‐Cuervo ME Durán H Tapio JM Gallardo FJ Peña C Ortega‐Ferrusola 《Reproduction in domestic animals》2014,49(6):1043-1048
Laparoscopic hernioplasty techniques have been developed in the recent years to avoid the recurrence of inguinal hernias and to spare the testicles for breeding purposes in stallions. However, there have been no previous comprehensive and systematic studies of the reproductive outcomes and prognoses for stallions after inguinal hernioplasty. Therefore, the objective of this study was to assess the possible effects of one of these techniques (standing laparoscopic peritoneal flap hernioplasty) on the sperm production and motility characteristics of six healthy stallions that received this procedure based on 1‐year follow‐ups. There were no significant differences in the measured sperm variables (assessments based on the DSO, MOT, PMOT, VSL, VCL and VAP) during 1‐year follow‐ups. 相似文献
40.
The relative influence of thermal and quantum fluctuations on the proton transfer properties of the charged water complexes H5O2+ and H3O2- was investigated with the use of ab initio techniques. These small systems can be considered as prototypical representatives of strong and intermediate-strength hydrogen bonds. The shared proton in the strongly hydrogen bonded H5O2+ behaved in an essentially classical manner, whereas in the H3O2- low-barrier hydrogen bond, quantum zero-point motion played a crucial role even at room temperature. This behavior can be traced back to a small difference in the oxygen-oxygen separation and hence to the strength of the hydrogen bond. 相似文献