Suitability of synthetic alkanes as markers for the estimation of passage rate in sheep

An experiment was conducted with eight adult wethers housed individually in metabolism crates to determine the suitability of alkanes to serve as passage rate markers in sheep. Two diets consisting of lucerne (800 g DM/d), without (treatment ‘Lucerne’) and with coarse maize meal (270 g DM/d; treatment ‘Lucerne–Maize’) were fed to four sheep per diet twice daily in equal proportions. Lucerne fibre was prepared from chopped lucerne silage and mordanted with chromium during 24 h cooking with sodium–lauryl–sulfate (Chromium–mordanted lucerne fibre: LF-_Cr). The synthetic alkane C36 was dissolved in heptane and sprayed onto lucerne fibre which had been similarly prepared (LF-_C36). C28 was dissolved in heptane and sprayed onto maize meal (M-_C28). Markers were fed at the same time as a pulse dose. For a period of 10 days, rectal grab faeces samples were taken in intervals of increasing length (2–12 h). A multi-compartment-model was fitted to the marker excretion curves.Maximum marker excretion appeared earlier for alkane markers than for Cr in both treatments. Within treatment Lucerne no significant differences between Cr and C36 were detected for Rumen mean retention time (MRT) (P > 0.05). Numerical differences were observed for RumenMRT in treatment Lucerne–Maize between LF-_Cr and LF-_C36 and M-_C28 (33, 25 and 25 h), respectively. Further numerical differences were observed in CaecumMRT for LF-_Cr and LF-_C36 in treatment Lucerne and for all markers in Lucerne–Maize. In treatment Lucerne, faecal recoveries of markers LF-_Cr and LF-_C36 were 95 and 85%, in treatment Lucerne–Maize 101 and 88%, and for M-_C28 in the treatment Lucerne-Maize only 75%.It was shown that the lower faecal recovery of alkanes by itself does not cause biased estimates of passage rate parameters. However, further investigations are necessary to determine the relationship between the time a particle has spent in the digestive tract and the disappearance of the alkane marker, as this could introduce a bias to the estimate.The major shortcoming of alkanes as passage rate markers seemed to be migration between solid and liquid phases of the digesta. This problem could be overcome by new labelling procedures or the use of ¹³C-labelled native alkanes.     

Determination of gastrointestinal passage rate using three different markers in laying hens

The titanium dioxide (TiO₂) marker technique is currently widely practiced as a method to evaluate gastrointestinal (GI) passage rate in poultry. However, this method requires sacrificing the animal to obtain digesta samples, is labour‐intensive and eliminates the possibility of follow‐up studies with the same individual. The aim of this study was to evaluate whether the radiographic methods barium‐impregnated polyethylene spheres (BIPS) and barium sulphate (BaSO₄) suspension are in agreement with the TiO₂ technique and can be used as an alternative method for GI passage rate determination in laying hens. Whole‐body radiographs were taken at different time points. Hens of group 3 (n = 55) were orally inoculated with 5 g of feed mixed with 0.15 g TiO₂, 5 hens per time point sacrificed, and whole gastrointestinal organs (crop, proventriculus, gizzard, small intestine and large intestine) were collected and analysed for TiO₂ content. The average marker passage rate of hens administered BaSO₄ was significantly faster than those administered BIPS (gizzard: 15.2 hr vs. 43.2 hr; small intestine: 15.2 hr vs. 38.4 hr, respectively). A greater percentage of BIPS remained in the crop at 0, 0.5, 2, 3 and 8 hr post‐inoculation (p.i.) and in the gizzard at 2, 24, 36 and 48 hr p.i. (all p < 0.05) compared to TiO₂. In conclusion, the evaluation of the GI transit time is feasible using BIPS, TiO₂ and BaSO₄. The evaluation of the GI transit time using BIPS and BaSO₄ needs further investigation.     

不同氮源日粮对绵羊瘤胃内烟酸的产生、消失及流通规律的研究

选用9只体重为35～43 kg安装永久性瘤胃瘘管的内蒙古半细毛羯羊,随机分为3组,每组3只,分别饲喂三种不同氮源日粮(即豆粕、麻饼、尿素-麻饼型日粮),本试验通过非同位素标记烟酸的启动、连续灌注方法,测定绵羊瘤胃烟酸的产生、消失及流通速率。试验结果表明,饲喂豆粕、麻饼、尿素-麻饼型日粮的绵羊瘤胃烟酸的基本产生速率分别为2.50、2.69、2.92 mg/h。通过灌注的方法提高烟酸产量后,烟酸在瘤胃内的产生速率分别为5.06、5.09、5.62 mg/h;消失速率分别为1.90、1.77、2.65 mg/h;瘤胃内烟酸的外流速率分别为3.16、3.32、2.97 mg/h。     

牛、羊全价颗粒饲料储存期间品质变化的研究

以牛、羊全价颗粒饲料为研究对象,探讨储存期间饲料的水分含量、粗灰分、粗脂肪、粗蛋白、粗纤维、钙、磷、菌落总数及霉菌总数等品质指标的变化。结果表明:随着储存时间的增加,水分含量、菌落总数与霉菌总数呈上升趋势,粗脂肪、粗纤维呈下降趋势,而对粗灰分、粗蛋白、钙、磷影响不大;牛、羊全价颗粒饲料在储存60 d时间内品质指标表现优异。     

Effects of wet corn gluten feed and intake level on diet digestibility and ruminal passage rate in steers

Twelve ruminally cannulated Jersey steers (BW = 534 kg) were used in an incomplete Latin square design experiment with a 2 x 2 factorial arrangement of treatments to determine the effects of wet corn gluten feed (WCGF) and total DMI level on diet digestibility and ruminal passage rate. Treatments consisted of diets formulated to contain (DM basis) steam-flaked corn, 20% coarsely ground alfalfa hay, and either 0 or 40% WCGF offered once daily for ad libitum consumption or limited to 1.6% of BW (DM basis). Two consecutive 24-d periods were used, each consisting of 18 d for adaptation, 4 d for collection, and a 2-d in situ period. Rumens of all steers were evacuated once daily at 0, 4, 8, and 12 h after feeding. Chromic oxide (10 g/[steer*d]) was fed as a digestibility marker, and steers were pulse-dosed with Yb-labeled alfalfa hay to measure ruminal particulate passage rate. Dacron bags containing 5 g of steam-flaked corn, WCGF, or ground (2-mm screen) alfalfa hay were placed into the rumens of all steers and removed after 3, 6, 12, or 48 h. Wet corn gluten feed increased percent apparent total-tract digestion of OM (P < 0.01), NDF (P < 0.01), and starch (P < 0.03), decreased (P < 0.01) ruminal total VFA concentration, increased (P < 0.01) ruminal NH3 concentration, and increased (P < 0.01) ruminal pH. Wet corn gluten feed also increased (P < 0.01) ruminal passage rate of Yb. Limit feeding decreased (P < 0.01) percent apparent total-tract digestion of both OM and NDF, ruminal total VFA concentration (P < 0.01), and ruminal fill (P < 0.01), but increased (P < 0.01) ruminal NH3 concentration. Apparent total-tract digestion of starch was not affected (P = 0.70) by level of DMI. A DMI level x hour interaction (P < 0.01) occurred for ruminal pH. Limit feeding increased ruminal pH before and 12 h after feeding, but decreased ruminal pH 4 h after feeding compared with diets offered ad libitum. A diet x DMI level interaction (P < 0.02) occurred for in situ degradation of alfalfa hay, with dietary addition of WCGF increasing (P < 0.02) the extent of in situ alfalfa hay degradation in steers fed for ad libitum consumption. This study suggests that WCGF increases OM and NDF digestion, and that limit feeding diets once daily might depress OM and NDF digestion, possibly due to decreased stability of the ruminal environment.     

A method of measuring the oviposition rate of the sheep blowfly, Lucilia cuprina under field conditions

A simple technique, which allows sheep to be rendered temporarily susceptible to fly attack, is described and used to examine oviposition rates of Lucilia cuprina under field conditions. Oviposition rates are shown to be related to both fly activity and fly density. The question of Hobson's 'live sheep factor' in attracting L. cuprina to sheep is re-considered.     

饲料中磺胺二甲基嘧啶的测定

用对-二甲氨基苯甲醛作显色剂,采用分光光度法测定饲料中磺胺二甲基嘧啶,最小检测量为0.05mg/kg,平均回收率分别为99.2%,变异系数≤5%,且该方法具有操作简便、快速,试剂消耗少,结果准确、离散程度小等优点。     

饲料用混合油脂在储存过程中氧化情况的研究

研究旨在观察饲料用混合油脂在储存过程中各氧化指标的变化规律,以得到评价饲料用混合油脂氧化程度的有效衡量指标。试验选用3批次豆油,3批次鱼油,10批次国产饲料用混合油脂以及2批次美国饲料级混合油,在室温下储存120 d,观察酸价、过氧化值、丙二醛值、茴香胺值和水提取物电导率5个指标的变化情况。结果表明,除酸价外其余四个指标都随着油脂储藏时间的延长呈不同程度的上升趋势,其中过氧化值和茴香胺值在饲料用混合油脂储藏过程中变化程度最为明显,试验结果表明,过氧化值和茴香胺值可以用作评价饲料用混合油脂氧化程度的敏感指标。     

Influence of the physical properties of straw pellets on their digestibility and passage rate of Cr2O3 in sheep

By means of pelleting them one to four times (press G 600) and adding 20% sugar beet chips and 3% ammonia hydrogen carbonate at varying loose density (357-561 kg/m3) 4 straw pellet charges were produced. Significant differences could be ascertained for these pellets with regard to the fineness coefficient (I-IV 1.67; 1.30; 1.19; 0.83), hardness of pellets (5.4; 8.8; 9.4; 18.6 N/m2/10(5) and partly the loose volume. After testing four wethers per group, an energy concentration in the same sequence was ascertained as follows: 409, 388, 377 and 382 EFUcattle/kg dry matter. Apart from a higher crude fibre digestibility of groups I and II compared to III there were no significant differences in the digestibility. The measuring of feed passage time with the help of Cr2O3 did not result in directed differences. On an average of all groups, 80% of the Cr2O3 excretion was achieved after 70.5 +/- 0.7 h. The mean retention time of Cr2O3 in the digestive tract in all four groups was in average 53.3 +/- 1.2 hours. The different fineness degrees and values of the hardness of straw pellets remained without significant effects on the feed value of the straw pellets in the experiments with sheep.     

Season-dependent effect of daily frequency of feed distribution on the rate of feed consumption and reproductive performance in sows during lactation

The effects of the daily frequency of feed distribution (once, One; twice, Two; and four times, Four,) on the rate of feed consumption (RFC) and reproductive performance were investigated in Large White sows farrowing in the hot season from June to September (H sows) and in the rest of the year (R sows). The RFC was greater in feeding treatment Four than Two (P < 0.01) in H sows; however, bodyweight loss during lactation was not affected by the feeding treatment. No difference in effects of frequency of feed distribution for sows was observed on piglet growth. The survival rate of the piglets was not different between feeding treatments. The number of sows that came into estrus within 7 days post‐weaning was smaller in the feeding treatment Four than One (P < 0.05) in H sows and those of Four than One (P < 0.01) and Two (P < 0.05) in R sows. These results suggest that in sows during lactation increasing the daily frequency of feed distribution may have a negative effect on reproductive performance.     

Serial passage of Haemonchus contortus in resistant and susceptible sheep

A recently isolated field strain of Haemonchus contortus was passaged through resistant (repeatedly reinfected) and susceptible (immunosuppressed) sheep for six and nine generations, respectively. Infectivity of the resulting serially passaged strains was not significantly different when tested in groups of 1-year-old susceptible sheep.     

饲料中沙丁胺醇快速检测技术研究

本实验在现有的克伦特罗检测系统上建立了沙丁胺醇的酶联免疫吸附检测体系。结果表明,该方法在饲料中沙丁胺醇的检测中完全可行。     

Route of passage of cypermethrin across the surface of sheep skin

14C cypermethrin applied topically to the dorsal surface of sheep moved radially across the skin within the stratum corneum of the epidermis at a rate which exceeded 11 cm h-1. This spread was accompanied by some dermal infiltration which was most marked at the site of application.     

放牧条件下鄂尔多斯细毛羊成年母羊四季牧草采食量测定

为了探讨鄂尔多斯细毛羊成年母羊四季放牧采食情况,实现鄂尔多斯细毛羊精准饲喂模式,采用饱和烷烃法对鄂尔多斯细毛羊成年母羊四季放牧采食量进行了测定。结果显示:鄂尔多斯细毛羊成年母羊春、夏、秋、冬四季放牧采食量分别为(2.24±0.15)kg、(3.32±0.23)kg、(1.60±0.21)kg、(0.93±0.14)kg;其中成年母羊以夏季采食量最高,显著高于(P0.05)春季和秋季,春、夏、秋3季均极显著高于冬季(P0.01)。提示:在放牧条件下,成年母羊应根据草场营养供给情况在冬季进行适当补饲。