酒糟及残液（DGS）在肉牛生产中的应用

乙醇产业的快速扩张也带来了相应的副产品（主要是酒糟及残液，DGS）产量的增加。DGS的养分（蛋白、脂肪、纤维等）浓度比玉米高约3倍，是反刍动物很好的蛋白质来源。随着玉米供应量的减少及价格的升高，DGS作为饲料能量来源也具有非常重要的意义。生产试验表明，与饲喂不含DGS的玉米基础日粮相比，用不同水平的湿或干DGS饲喂育肥牛，均可提高日增重（ADG）和饲料报酬（G：F）。代谢试验表明，DGS中的脂肪在瘤胃降解较低，可增加十二指肠不饱和脂肪酸的比例和脂肪的全消化道消化率，DGS中的脂肪和非降解蛋白可能是DGS饲用价值高于玉米的重要原因。DGS还有助于提高育肥目粮中低质粗饲料的利用效果。DGS的饲用价值要好于干压玉米和高湿玉米，但DGS用于蒸汽压片玉米基础日粮中的效果低于在干压或高湿玉米基础日粮中的效果。     

BOARD-INVITED REVIEW: Use of distillers by-products in the beef cattle feeding industry

The ethanol industry is expanding rapidly. This expansion in production of renewable energy also increases production of by-products. These byproducts, primarily distillers grains plus solubles (DGS), are utilized very efficiently by ruminants. When the starch in corn is fermented to produce ethanol, the remaining nutrients (protein, fat, fiber) are concentrated about 3-fold. Whereas DGS is an excellent protein source for ruminants, the large supply and the price relative to corn make DGS an attractive energy source as well. This is especially important with reduced availability and higher price of corn because of demand by the ethanol industry. A meta-analysis of 9 experiments, where various levels of wet DGS were fed to feedlot cattle, shows that wet DGS produced higher ADG and G:F compared with cattle fed corn-based diets without DGS. A similar analysis with dry DGS showed similar type of responses but with less apparent feeding value for dry DGS compared with wet DGS. Metabolism studies suggest the fat in DGS may be partially protected from ruminal degradation leading to greater proportion of unsaturated fatty acids at the duodenum and greater total tract fat digestibility. Both the fat and the undegradable protein in DGS appear to explain some but not all of the greater feeding value of DGS compared with corn. Lower quality roughages may be used in feedlot diets containing wet DGS because of the protein, moisture, and physical characteristics the DGS contains. The feeding value of DGS is greater than dry-rolled corn or high moisture corn; however, the feeding value of DGS appears to be less when fed in finishing diets based on steam-flaked corn than in those based on dry-rolled or high-moisture corn.     

南方湿热气候地带提高肉牛育肥效果的生产环节控制

为了给南方湿热气候地带肉牛的育肥提供参考,文章从肉牛育肥生产的4个重要环节论述了如何选择开始育肥的时间、育肥的期限、架子牛的始重和育肥饲料,以提高在南方(尤其是岭南地带)肉牛育肥的生产效益。建议在岭南湿热地带育肥肉牛开始时间以10月下旬或11—12月份较佳;育肥架子牛年龄、体重应尽量接近,周岁以上犊牛年龄相差以不超过2～3个月为宜,体重差异应控制在1个标准差以内;育肥模式可选择秋末、冬春的非热季节3～6个月短期育肥、从第1年的1月底或2月初开始的跨年度12个月育肥和从第1年秋末开始的跨3个年度的18～24月的长期育肥3种育肥模式;育肥饲料应按照育肥阶段提前准备,渐进式地更换饲料品种类型和数量;并从牛的种质、驱虫防病、每日最佳投料时间和确定产品适时上市等方面提出了持续增加育肥生产效益的可选择环节。     

Intensive fattening of beef cattle by stall feeding on the Lilongwe plain,Malawi II. Utilisation of crop residues,crop by-products and leucaena

Summary Experiments were conducted over three dry seasons to investigate the value for fattening beef cattle, of crop residues (maize stover, groundnut haulm) and madeya (maize bran) with varying levels of dried leucaena leaf or cottonseed cake.The inclusion of groundnut haulm in the roughage increased animal performance when madeya was restricted. Increasing the protein content of the madeya supplement but restricting the quantity of madeya fed did not influence liveweight gain although the efficiency of concentrate conversion was enhanced.Restricting the amount of maize stover and feeding madeya to appetite had no significant effect on liveweight gain, but the inclusion of leucaena up to a level of 12 per cent crude protein improved animal performance. There were no differences between cottonseed cake or leucaena when fed with madeya at the same levels of crude protein.

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Engorde Intensivo De Ganado De Carne En Confinamiento En Las Sabanas De Lilongwe, Malawi. II. Utilizacion De Residuos De Cosechas, Subproductos Y Leucaena

Resumen Se llevaron a cabo experimentos durante tres períodos secos, tendientes a investigar el valor para el engorde de ganado, de residuos de cosechas (tallos de maïz, paja de maní) y madeya (salvado de maïz) con varios niveles de hoja seca de leucaena y torta de algodón.La inclusión de paja de maní en el forraje, incrementó el rendimiento animal cuando el salvado de maïz se restringió. Incrementando el contenido proteico del salvado de maïz y al mismo tiempo restringiendo su consumo, no hubo influencia alguna en ganancia de peso, aunque la eficiencia de conversión del concentrado aumentó.Restringiendo la cantidad de tallo de maïz y dando salvado a discreción no hubo un efecto significativo en el aumento de peso; pero la inclusión de leucaena a niveles del 12 por ciento de proteína cruda aumentó el rendimiento animal. No se detectaron diferencias entre la torta de algodón y leucaena cuando se dieron con salvado de maïz, con el mismo nivel de proteína cruda.

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Engraissement Intensif De Bovins De Boucherie Par Embouche En Etable Dans Les Plaines De Lilongwe, Au Malawi. II.—Utilisation De Residus Et De Sous Produits De Cultures Et De Leucaena

Résumé Les expériences ont eu lieu durant trois saisons sèches pour déterminer la valeur des résidus de cultures (maïs, fourrage, fanes d'arachide) et du son de maïs accompagnés de quantités variables de feuilles sèches de leucaena et de tourteau de graines de coton dans l'engraissement du bétail de boucherie.L'addition de fanes d'arachide dans la ration a augmenté les performances des animaux lorsque le son de maïs a été réduit. L'augmentation du taux de protéines du complément de son de maïs, mais en réduisant la quantité de son consommé, n'a pas d'influence sur le gain de poids vif bien que l'efficacité de la conversion du concentré soit augmentée.La diminution de l'apport de maïs foureage et l'alimentation en son de maïs n'a eu aucun effet sur le gain de poids mais, en ajoutant des feuilles de leucaena jusqu'à élever le taux brut des protéines à 12 p. 100, a augmenté les performances des animaux.Il n'yaeu aucune différence entre le tourteau de graines de coton et le leucaena quand l'alimentation avec le son de maïs a été élevée au même taux brut de protéine.

     

Transmission and control of leptospiral infection in a beef cattle herd in southern alberta

Leptospiral antibodies were detected in unvaccinated cattle on a 17 000 hectare ranch in the arid southeast region of Alberta. Antibody to serovar hardjo was present before the breeding season in 7% of 42 yearling bulls, 86% of 29 two year old bulls and 5% of 519 cows. Pomona antibody was confined to 3.7% of the cows. Bulls were treated once with dihydrostreptomycin, 25 mg/kg. Bulls and cows were vaccinated twice at a six week interval, with pomona-hardjo-gripptotyphosa bacterin before breeding and cows were revaccinated the next year. Leptospires were demonstrated in urine, kidney and spinal fluid of vaccinated and treated cattle. New infections occurred on range in vaccinates. Eighteen months after the last vaccination, hardjo and pomona antibody prevalences in cows were 3.6 and 3.2% respectively. A group of 250 seronegative cows on the same ranch were not vaccinated. They remained seronegative throughout the 2.5 years of the study. These cows, in contrast to infected groups, were excluded from pastures adjacent to perimeter herds and grazing leases, and they were bred by artificial inseminstion. Rotation through pastures in common with infected groups, and exposure to seropositive heat detector bulls, did not result in seroconversion in these cows. The study showed the potential of range bulls to amplify and transmit hardjo infection, limitations to the value of treatment and vaccination with available agents, and the potential of management practices to maintain an uninfected herd in close proximity to cattle carrying hardjo infection.     

A survey of fascioliasis in beef cattle killed at abattoirs in southern Queensland

The overall prevalence of fascioliasis in beef cattle found in an abattoir survey completed in May 1983 in southern Queensland, was 1.1%. Prevalence was 36% in the Stanthorpe Shire, varied from greater than 1 to 10% in 12 shires and was 1% or less in 24 shires. Fascioliasis was not recorded from the other 46 shires in the area of the survey. Prevalence was less than 1% in female cattle of all ages. In males, prevalence increased with age from 0.6% in 17-month-old cattle to 4.7% in 4-year-old cattle. The differences in sex-specific prevalences may be due to differences in susceptibility to the parasite between sexes, differences in susceptibility to the parasite between sexes, differences in management between sexes, or artefacts associated with sampling for a disease of very low prevalence. The presence of the exotic snail species, Lymnaea columella and L. viridis was confirmed in southern Queensland in 1977. These snails are suitable intermediate hosts for Fasciola hepatica and may widen the endemic area for liver fluke because of their more aquatic character and greater tolerance to high temperatures than L. tomentosa, the traditional snail host in Queensland. We suggest that introduced snails have not yet had a substantial impact on the importance of fascioliasis to the beef industry of southern Queensland. The survey provides baseline data for the future monitoring of this potentially important parasitic disease.     

DDGS和其他来源的粗饲料在肉牛生产上的应用研究

两组试验用来评估当在蒸汽压片玉米（SFC）日粮中添加玉米DDGS和苜蓿干草（AH）或者玉米青贮（CS）的肉牛的胴体品质、瘤胃发酵或日粮代谢的影响。在试验1中,358头体重为353±13kg的杂交母牛被用来评估玉米DDGS和AH（或CS）对肉牛胴体品质的影响,试验日粮分为4组,分别为：SFC-CS日粮,即蒸汽压片玉米（SFC）和11%青贮料（CS）;DDGS-CS日粮,即蒸汽压片玉米（SFC）和11%青贮料（CS）以及25%DDGS;SFC-AH日粮,即蒸汽压片玉米（SFC）和6%AH;DDGS-AH日粮,即SFC和25%DDGS以及6%AH。所有的牛每天自由采食,试验时间为97d。结果显示,饲喂DDGS没有影响肉牛的平均日增重（ADG,P=0.19）、干物质采食量DMI（P=0.14）以及饲料转化率（P=0.67）。饲喂CS的肉牛要比饲喂AH的肉牛的DMI高（P=0.05）,但ADG（P=0.56）和G：F（P=0.63）没有太大差别;各处理组的肉牛热胴体重（HCW）、屠宰率、皮下脂肪厚度以及牛肉产量、质量等级的差别也不大（P〉0.20）;饲喂CS组的肉牛相对饲喂AH肉牛有降低大理石花纹评分分数的趋势。在第2个试验中,12头荷斯坦奶牛用来评估各种日粮的肉牛瘤胃发酵和日粮代谢的差异。结果显示,饲喂后14h所有处理组的肉牛瘤胃pH值低于5.8,饲喂25%的DDGS组的肉牛瘤胃的乙酸和丙酸的比率较低（P=0.02）,但瘤胃乳酸浓度要比未添加DDGS组的高（P=0.02）。饲喂25%的DDGS组的肉牛瘤胃氨气浓度有所下降（P〈0.01）。这说明当在肉牛蒸汽压片玉米日粮中添加DDGS可以提高饲料转化率。     

用莫能菌素育肥肉牛应注意的几个问题

商品肉牛的育肥对饲养管理条件、营养水平均要求较高,如在日粮中加入莫能菌素(又称瘤胃素),能较好地促进肉牛的育肥进程,提高肉牛育肥的效益,但需要注意以下几个问题。     

Control of cattle mange in southern africa using ivermectin

Seven trials including 768 cattle were conducted in South Africa and Namibia to evaluate the efficacy of the systemic parasiticide ivermectin when administered subcutaneously at a dose rate of 200 micrograms/kg against sarcoptic (Sarcoptes scabiei var. bovis), chorioptic (Chorioptes bovis) and psoroptic (Psoroptes ovis var. bovis) mange mites. The efficacy of a single treatment against Psoroptes and Sarcoptes was greater than against Chorioptes. There was marked clinical cure in all treated cases with loss of crusts and hair regrowth. The number of cases of psoroptic mange in two large herds, of which 42.4% of 724 animals were clinically affected prior to mass treatment, was reduced by 99.3% following a single subcutaneous treatment with ivermectin; a single animal from which mites were recovered may not have been treated. The apparent prevalence and prospects for control and eradication of cattle mange in South Africa and Namibia are discussed.     

Predicting copper status in beef cattle using serum copper concentrations

Copper deficiency is common in pasture-fed cattle in New Zealand⁽¹⁾. In general, the diagnosis of copper deficiency in a herd of cattle is based on a combination of history, examination of animals, examination of the environment, chemical analysis of blood, liver or pasture, and treatment response trials. The laboratory diagnosis of copper deficiency is currently based on liver and either plasma or serum concentrations of copper. Ellison⁽²⁾ reviewed the copper reference range for cattle used by the animal health laboratories in New Zealand and concluded that there is strong agreement in the literature that serum copper concentrations greater than 7.9 𝛍mol/l and liver copper concentrations greater than 95 𝛍mol/kg are adequate for young cattle. Furthermore, it has been reported that if copper concentrations in the liver are greater than 150–200 𝛍mol/kg wet weight, there is a negligible increase in serum copper as liver concentrations increase further⁽²⁾, with individual animal variation accounting for the range of values in serum copper at this point (7.9–18 𝛍mol/l).     

无公害肉牛饲养与管理

近几年来,肉牛市场价格一路走高、效益可观,促进了养牛业的发展,增加了农民养牛的积极性。生产无公害绿色肉牛产品,是稳占国内市场,拓展国际市场的必然趋势。本文结合黑山县实际情况对无公害肉牛饲养与管理做以介绍．     

Two methods for parameter estimation using multiple-trait models and beef cattle field data

Two methods are presented for estimating variances and covariances from beef cattle field data using multiple-trait sire models. Both methods require that the first trait have no missing records and that the contemporary groups for the second trait be subsets of the contemporary groups for the first trait; however, the second trait may have missing records. One method uses pseudo expectations involving quadratics composed of the solutions and the right-hand sides of the mixed model equations. The other method is an extension of Henderson's Simple Method to the multiple trait case. Neither of these methods requires any inversions of large matrices in the computation of the parameters; therefore, both methods can handle very large sets of data. Four simulated data sets were generated to evaluate the methods. In general, both methods estimated genetic correlations and heritabilities that were close to the Restricted Maximum Likelihood estimates and the true data set values, even when selection within contemporary groups was practiced. The estimates of residual correlations by both methods, however, were biased by selection. These two methods can be useful in estimating variances and covariances from multiple-trait models in large populations that have undergone a minimal amount of selection within contemporary groups.     

Performance of cattle stall-fed for beef in Malawi

Information on the initial and final weights, length of feeding period, grade of the live animal before slaughter, carcass weight and dressing percentage of 2,498 stall fed Malawi zebu (MZ) and crossbred steers from Southern Region and 2,085 steers from the Central Region of Malawi is analysed. Agricultural and household residues were the basis of the feeding system. The genetic composition of individual animals was not known; weight groups were therefore used as proxies for breed types. Final weights were significantly influenced by breed, month and year when the feeding period was started and breed by month interactions. The mean stall feeding period in the South was 188 days and the average daily gain was 0.59 kg. Steers in the Central Region were fed for 213 days and gained on average 0.50 kg per day. Breed did not exert a significant effect on weight gain. However, when daily gain was compared on the basis of metabolic body size, MZ i.e. smaller steers gained significantly more rapidly than crossbred steers. The dressing percentage of animals from both regions was 52.3%. The carcass weight of crossbred steers was higher than that of MZ steers. It is concluded that an effective fattening system can be based on locally available resources and a similar system could be suitable for other parts of the developing world.     

蒙东地区肉牛养殖现状及效益分析

对蒙东地区肉牛的饲养品种、存栏量、养殖规模、饲养水平、疫病防治、生产情况及市场行情等进行了系统地跟踪调研,对蒙东地区肉牛的饲养管理、产犊育肥、盈利水平等情况进行了客观的分析,详细地阐述了蒙东地区肉牛养殖的生产现状,为肉牛的高效养殖和产业健康发展提供了数据参考。     

Genetic and phenotypic parameter estimates for feed intake and other traits in growing beef cattle, and opportunities for selection

Growth, feed intake, and temperament indicator data, collected over 5 yr on a total of 1,141 to 1,183 mixed-breed steers, were used to estimate genetic and phenotypic parameters. All steers had a portion of Hereford, Angus, or both as well as varying percentages of Simmental, Charolais, Limousin, Gelbvieh, Red Angus, and MARC III composite. Because the steers were slaughtered on various dates each year and the animals thus varied in days on feed, BW and feed data were adjusted to a 140-d feeding period basis. Adjustment of measures of feed efficiency [G:F or residual feed intake (RFI), intake adjusted for metabolic body size, and BW gain] for body fatness recorded at slaughter had little effect on the results of analyses. Average daily gain was less heritable (0.26) than was midtest BW (MBW; 0.35). Measures of feed intake had greater estimates of heritability, with 140-d DMI at 0.40 and RFI at 0.52; the heritability estimate for G:F was 0.27. Flight speed (FS), as an indicator of temperament, had an estimated heritability of 0.34 and a repeatability of 0.63. As expected, a strong genetic (0.86) correlation was estimated between ADG and MBW; genetic correlations were less strong between DMI and ADG or MBW (0.56 and 0.71). Residual feed intake and DMI had a genetic correlation of 0.66. Indexes for phenotypic RFI and genotypically restricted RFI (no correlation with BW gain) were compared with simple economic indexes incorporating feed intake and growth to elucidate expected selection responses under different criteria. In general, few breed differences were detected across the various measurements. Heterosis contributed to greater DMI, RFI, and MBW, but it did not significantly affect ADG, G:F, or FS. Balancing output (growth) with input costs (feed) is needed in practicing selection, and FS would not be recommended as an indicator trait for selection to change feed efficiency. An index including BW gain and RFI produced the best economic outcome.     

Predicting carcass composition of beef cattle using ultrasound technology.

We evaluated 20 slaughtered cattle with ultrasound before hide removal to predict fat thickness and ribeye area at the 12th rib for possible use in carcass composition prediction. Carcasses were fabricated into boneless subprimals that were trimmed progressively from 2.54 to 1.27 to .64 cm maximum fat trim levels. Stepwise regression was used to indicate the relative importance of variables in a model designed to estimate the percentage of boneless subprimals from the carcass at different external fat trim levels. Variables included those obtained on the slaughter floor (ultrasound fat thickness and ribeye area; estimated percentage of kidney, pelvic, and heart [KPH] fat; and warm carcass weight) and those obtained from carcasses following 24 h in the chill cooler (actual fat thickness, actual ribeye area, estimated percentage of KPH fat, warm carcass weight, and marbling score). At all different subprimal trim levels, percentage KPH was the first variable to enter the model. In the models using measures taken on the slaughter floor, ultrasound fat thickness was the only other variable to enter the model. Ultrasound fat thickness increased R2 and decreased residual standard deviation (RSD) in models predicting subprimals at 2.54-cm maximum fat trim; however, at 1.27- and .64-cm trim levels, R2 and RSD increased. Models using the same two variables (except actual fat instead of ultrasound) in the cooler were similar to those using data from the slaughter floor. However, as more cooler measurement variables entered the models, R2 increased and RSD decreased, explaining a greater amount of the variation in the equation. Ultrasonic evaluation on the slaughter floor may be of limited application compared with the greater accuracy found in chilled carcass assessment.