Ceruloplasmin as an indicator of copper status in cattle and sheep.

The relationship between ceruloplasmin, a metalloenzyme with oxidase activity, and copper was investigated in cattle and sheep. The oxidase activity of ceruloplasmin correlated closely with the serum or plasma copper concentrations in cattle. The respective correlation coefficients were 0.83 and 0.60. In sheep serum, a correlation coefficient of 0.92 was obtained. In each instance, the relationship remained linear from the deficient to the high normal ranges of copper. Comparison of the linear regression relationships indicated the ceruloplasmin activity in bovine serum was statistically lower than the activity in bovine plasma (P less than 0.0001), through the intercepts from the regression lines of the two relationships were similar (P = 0.412). Comparisons of ovine and bovine serum-ceruloplasmin relationships indicated that a significant species difference was present. Ovine ceruloplasmin activity increased more rapidly as compared to the corresponding bovine activity over the range of copper concentrations investigated (P less than 0.0001). The intercept from the ovine regression relationship was also lower (P less than 0.0001). A correlation coefficient of 0.35 was observed between the serum ceruloplasmin activity and hepatic copper concentrations in cattle indicating that the mathematical relationship was not as well defined. Ceruloplasmin activity appears to correlate more closely with serum or plasma copper concentrations as compared to corresponding liver copper concentrations.     

Relationships between mineral concentrations and physicochemical characteristics in the Longissimus thoracis muscle of Japanese Black cattle

The relationship between mineral concentrations, and the relationship of mineral concentrations with physicochemical characteristics in muscles were investigated using the Longissimus thoracis (LT) muscle of 44 Japanese Black steers. We determined moisture content, fat content, meat color, fatty acid composition and mineral concentrations in the LT muscle. Magnesium (Mg), potassium (K) and zinc (Zn) concentrations had negative correlations with fat content, but sodium (Na), manganese (Mn), copper (Cu) and molybdenum (Mo) concentrations were not correlated with fat content. The concentrations of Mg, Mn, Fe, Cu and Zn largely and positively contributed to the first principal component of mineral concentrations. Because the red muscle was rich in these minerals compared to the white muscle, the variation of these minerals probably results from the abundance of red fibers in the LT muscle. The concentration of K was positively correlated with moisture content but Na concentration was not related to moisture content, suggesting that the intracellular fluid volume can largely affect moisture content. The results of the present experiment suggest that mineral concentrations reflect some traits such as not only fat content but also the composition of myofiber type and the intracellular fluid volume in the LT muscle of Japanese Black cattle.     

播量与水肥耦合对河北秋闲田饲用谷子产量的影响

为研究不同播量与水肥(N、P、K)耦合效应对河北秋闲田饲用谷子(Setaria itlica)产草量的影响,以冀谷18为材料,采用五元二次回归正交旋转组合设计进行盆栽试验,通过建立饲用谷子干草产量(Y)与土壤含水量(x1)、N(x2)、P(x3)、K(x4)以及播量(x5)之间的数学模型,模拟寻优。结果表明,水分、播量、磷肥、钾肥等对产草量有重要影响,其中,水分对产量的影响最大,其次是播量、磷肥、钾肥;播量与水肥耦合的显著项及其强弱顺序为:水分+播量钾肥+播量氮磷耦合水氮耦合水磷耦合;其他各项没有明显影响。构建了数学模型Y=20 543.756-565.570x1-39.942x2-23.102x3-38.470x4-151.877x5+1.052x1x2+1.604x1x3+12.953x1x5-0.173x2x3+0.737x4x5-2.292x52,其决定系数R2=0.788,显著值Sig.=0.0000.01,差异极显著,FLf=0.464F0.1=2.193,失拟性不显著,表明该模型预测结果可靠程度较高。明确了以经济效益为考核指标的最优方案:土壤含水量保持10%、饲用谷子播量15kg/hm2。该方案干草产量为14 037.15kg/hm2,经济效益为13 887.15元/hm2,较最优组合增收3 288.98元/hm2,增幅23.68%。为秋闲田饲用谷子生产实践提供了理论依据和技术支撑。     

Influence of copper supplementation on blood and liver copper in cattle fed tall fescue or quackgrass

Copper concentrations were measured in naturally Cu-deficient and Cu-supplemented yearling Hereford heifers fed tall fescue (Festuca arundinacea Schreb.) or quackgrass (Agropyron repens [L] Beauv.) forage. The data were used to establish a relationship between dietary Cu supplementation and accumulation of liver Cu, and to test the influence of diet and Cu supplementation on blood plasma Cu and ceruloplasmin oxidase activity. Dietary Cu supplementation was positively correlated with accumulation of liver Cu; the rate of increase in liver Cu levels diminished at high supplementation rates (liver Cu = 410.43 - 353.47 x e-.00295 x mg Cu supplement; R2 = .740), suggesting an efficient mechanism preventing fast, toxic Cu-overloading in cattle. The linear relationship (R2 = .7878) between blood plasma Cu and ceruloplasmin oxidase activity indicated that similar percentages of blood plasma Cu were present as ceruloplasmin in deficient, normal and Cu-supplemented cattle. However, the portion of plasma Cu occurring as ceruloplasmin changes significantly with type of feed. When compared with quackgrass, tall fescue not only produced rapid Cu depletion in unsupplemented cattle, but affected intermediary Cy metabolism and activity of Cu-enzyme ceruloplasmin differently at all levels of experimental Cu supplementation.     

12月龄雷琼黄牛生长曲线拟合的比较分析

为研究雷琼黄牛的早期生长发育规律,试验测量了300头不同月龄雷琼黄牛的体重和体高等生长指标,以SPSS 21.0软件进行相关性分析,再分别利用Brody、Von Bertalanffy、Logistic和Gompertz四个模型对试验牛的体高、胸围、体斜长和体重进行了拟合分析.结果表明:12月龄雷琼黄牛体高(x2)、腹...     

豚鼠动物模型评价牛口蹄疫Asia-1型灭活疫苗效力的研究

以豚鼠为试验动物模型,探索一种应用豚鼠替代牛进行牛口蹄疫Asia-1型灭活疫苗效力检验的方法.豚鼠和牛同步对6批牛口蹄疫Asia-1型灭活疫苗进行PD50效力检验,其中2批进行重复性试验.豚鼠分别在免疫后7、14、21和28天采血检测Asia-1型的中和抗体水平.统计学分析显示,测定的豚鼠PD50和牛PD50之间具有极...     

Multivariate regression analysis of epidural pressure in cattle

OBJECTIVE: To evaluate the effects of growth, maturity, and pregnancy on epidural pressure in cattle. ANIMALS: 50 healthy Holstein cattle (18 heifers, 23 lactating cows, and 9 pregnant nonlactating cows). PROCEDURE: Each of the cattle was restrained in a standing position. Height of the second lumbar vertebra's transverse process (2LTP) and humeral tuberosity (HT) on the right side as well as abdominal girth (AG) were measured in each animal, and body condition score (BCS) was ascertained. Skin caudal to the first lumbar spinous process was aseptically prepared, and anesthetic was injected. After inserting a 16-gauge 120-mm Tuohy needle in the ligamentum flavum, a calibrated pressure transducer was connected to the needle. Then, the needle was introduced into the epidural space, and epidural pressure was recorded. RESULTS: Mean +/- SD residual epidural pressure of heifers (-9.3+/-3.3 mm Hg) was significantly higher than that of lactating (-174+/-5.5 mm Hg) or nonlactating (-14.5+/-2.4 mm Hg) cows. Stepwise regression of 5 variables revealed that only the difference in height between 2LTP and HT (2LTP - HT) in heifers and only BCS in lactating cows were significantly correlated with residual epidural pressure. For all cattle, the optimal equation (R2 = 0.47) describing the relationship was y = -12.7 + 6.3x, - 0.4x2 - 0.1x3, where y is epidural pressure, x1 is BCS, x2 is 2LTP - HT, and x3 is age. CONCLUSIONS AND CLINICAL RELEVANCE: Negative epidural pressure was detected in standing cattle. Growth, maturity, and pregnancy affect epidural pressure in cattle.     

Effect of excess dietary sodium, potassium, calcium and phosphorus on excreta moisture of laying hens

1. Four experiments were conducted to investigate the effects of dietary concentrations of sodium, potassium, calcium or phosphate on the water intake and excreta moisture of laying hens. A fifth experiment examined the effect on these variables of increasing amounts of 2 different sodium salts (chloride or bicarbonate) and the interactions with 2 levels of dietary phosphorus. 2. All experiments involved individually caged laying hens fed on diets varying in 1 or 2 minerals in replacement for washed sand. The experimental diets contained mineral concentrations that either met or exceeded the expected requirement of the hens. The diets were given for a 7 or 8 d feeding period and food and water intakes were measured and excreta were collected for the last 48 h of each feeding period. These data were corrected for evaporative water loss to the environment during the collection period. 3. Increasing dietary concentrations of sodium, potassium or phosphorus gave linear increases (P<0.001) in the water intake of the laying hens and linear increases (P<0.01) in the moisture content of their excreta. Each 1 g/kg increase in dietary mineral increased the moisture content of the excreta by 9.04 (+/- 1.57), 11.95 (+/- 2.02) and 5.59 (+/- 0.31) g/kg (+/- standard error) for sodium, potassium and phosphorus, respectively. Increasing concentrations of dietary calcium did not significantly affect the water intakes or excreta moisture levels of the laying hens. 4. The fifth experiment showed that, although there was a sodium x phosphorus interaction (P<0.05), the effects of the 2 mineral additions were approximately additive. There were no significant differences (P>0.05) in water intakes or excreta moisture contents due to the 2 different sodium salts (chloride or bicarbonate).     

Relationship between fecal crude protein concentration and diet organic matter digestibility in cattle

The positive relationship between fecal CP concentration and diet OM digestibility in cattle, which is based on increasing undigested microbial CP and decreasing fecal OM as OM digestibility increases, may be used as an indirect method for estimating diet OM digestibility from fecal CP concentration. Results of digestibility trials (445 individual observations) conducted at Hohenheim and Braunschweig, Germany, and at Gumpenstein, Austria, were used to study the relationship between CP concentration in feces (x, g/kg OM) and OM digestibility (y, %). The best fit was obtained with the curvilinear relationship y = ai -107.7e(-0.01515 x x), with a1 = 79.76 and a2 = 72.86 (R2 = 0.82; residual SD = 2.7; SE = 0.13), which takes into account the effects of location (i = 1 for Braunschweig and Hohenheim, and i = 2 for Gumpenstein). Dietary CP and crude fat concentration, and DMI had no effect on fecal CP content, whereas crude fiber content, proportion of concentrate in the diet, and forage type significantly affected CP concentration in feces; however, the magnitude of these effects was less than 2 percentage units, and the direction of the effect of proportion of concentrate in the diet was not uniform. The curvilinear relationship between fecal CP concentration (observed range, 100 to 300 g/kg of OM) and diet OM digestibility (observed range = 57 to 80%) may be used to estimate diet OM digestibility, particularly for field trials, as it requires no feed samples and does not physically restrict the animal.     

黑土滩恢复演替过程中植物功能群及牧草品质变化

应用空间序列代替时间序列的方法,对高寒草甸不同恢复演替阶段黑土滩植物群落结构、植物功能群及牧草品质的变化进行了研究。结果表明:物种数与演替梯度间呈显著正相关关系:y=5.594x+0.643,(R²=0.8811);Shannon指数与演替梯度间呈非线性单峰曲线关系:y=-0.0528x²+0.6584x+0.3874(R²=0.7531);生物量与演替梯度间亦呈单峰曲线关系:y=-8.7647x²+86.696x+67.14(R²=0.6164)。一年生植物在群落中的数量呈下降趋势;禾本科植物在群落中的数量呈上升趋势;莎草类及杂类草植物在群落中的数量均呈增加趋势,但莎草类植物增幅不大,而杂类草植物则急剧增加。牧草品质随演替时间的延长而发生不同的变化:劣等牧草生物量在群落中呈下降趋势;中等和优等牧草生物量的变化趋势相同:随着演替时间的增加,均呈现幅度较大的增加趋势;而良等牧草生物量的变化则与之不同,生物量的峰值出现在演替的4-5年间。随着黑土滩的恢复演替,植物群落结构、功能群类型及草地生产性能均发生了重要变化。     

The effect of long-acting injectable selenium formulations on blood and liver selenium concentrations and liveweights of red deer (Cervus elaphus)

AIM: To evaluate the efficacy of a new long acting injectable selenium ( Se ) formulation to increase the Se status and prevent Se deficiency in red deer. METHODS: Groups of weaned red deer (four stags and six hinds/group) grazing pastures containing <30 mg Se/kg DM were injected subcutaneously with either 0.5, 1.0 or 2.0 mg Se/kg as a new formulation of BaSeO4 (Deposel Multidose), 1.0mgSe/kg of a current formulation (Deposel), or not treated. Blood Se concentrations and liveweight were measured nine times at intervals over 377 and 270 days, respectively. RESULTS: Both formulations of Se elevated blood Se concentrations from 105 nmol/l pre-injection for at least 377 days with peak levels of 1894, 1395 and 818 nmol/l for high, medium and low doses of Deposel Multidose, respectively, at 73141 days, and 1508 nmol/l at 73-141 days for the medium dose of Deposel, which persisted at similar levels for the duration of the study. Deposel Multidose produced fewer and less severe subcutaneous tissue reactions than Deposel. Pastures contained 10 to 30 mg Se/kg DM. There was no significant difference in growth rate between treated and control deer. There was a significant (p<0. 01) linear relationship (y = 1.25x + 71.6, R2=0.86) between blood (x) and liver (y) Se concentrations in the range of 120 - 2100 nmol/l for blood concentrations, and 200 - 3000 nmol/kg for liver concentrations. CONCLUSION: Injections of BaSeO4 in both formulations studied were effective in increasing the Se status of deer but the new formulation produced fewer and less-severe tissue reactions. Young growing red deer appear less sensitive to Se deficiency as measured by weight gain, than sheep and cattle, suggesting that reference ranges for those species are not appropriate for deer. There was a linear correlation between blood and liver selenium concentrations.     

Field method for monitoring blood glucose in beef cattle.

The purpose of this study was to determine the applicability of the Accu-Chek Easy (ACE) human self-monitoring system for monitoring glycemic status in cattle. The ACE method was compared with the Yellow Springs Instrument (YSI) analytical laboratory method in two studies. A preliminary study (62 samples) and a primary study (434 samples) involved a nine-fold range and a 10-fold range, respectively, of glucose concentrations obtained during the acute phase response of growing beef cattle to injections of varying dosages of endotoxin. The ACE monitoring method compared with the YSI analytical method resulted in similar patterns of glucose concentration change, similar ranking of glucose means across endotoxin dosages during hyper-and hypoglycemia, and a close relationship between paired YSI and ACE concentrations from common samples. The ACE method identified all nine animals that displayed hypoglycemic distress during the acute phase response to endotoxin injection. The relationship between the YSI analytical method and the ACE monitoring method was found to be nonlinear (YSI = -38.2+13.6.ACE.50; R2 = .99; Sy.x = 7.3 mg/dL), and the use of this equation to predict YSI values from ACE values in an independent data set resulted in linearity when YSI was regressed on the predicted YSI values (YSI = -.78+1.00.Predicted YSI; R2 = .87; Sy.x = 6.9 mg/dL). Even though variation seemed greater for ACE than for YSI, we concluded that a system developed for human self-monitoring of blood glucose, such as the ACE, can be used to monitor the glycemic status of cattle.     

牛奶中土霉素对青海弧菌和费氏弧菌的毒性作用测定

本文通过应用费氏弧菌和青海弧菌,探究了牛奶中土霉素对这两种发光细菌的毒性抑制作用规律。牛奶中,一定浓度下,土霉素对青海弧菌生物发光的抑制率随作用时间呈对数趋势增加,在0.45mg/L作用下,该关系方程为y=0.3007ln（x）-0.1940,R2=0.9934;作用5min时,土霉素抑制率随着浓度变化的规律呈直线关系,之后呈对数关系,E50值在5min时为0.75mg/L,30min时降低至0.12mg/L;土霉素对费氏弧菌生物发光的抑制率随作用时间呈对数趋势增加,在0.55mg/L作用下,y=0.2742ln（x）-0.0942,R2=0.9961;其抑制率随着浓度变化的规律在5min呈指数关系,之后呈对数关系,在作用10min时,y=0.5524ln（x）＋0.9045,R2=0.9949,E50值在5min时为0.75mg/L,40min时降低至0.09mg/L。     

The influence of level of feeding on growth and serum insulin-like growth factor I and insulin-like growth factor-binding proteins in growing beef cattle supplemented with somatotropin

The objective of this study was to determine the effects of level of feeding on growth, feed efficiency (gain:feed; G:F), body composition (BC), and serum concentrations of somatotropin (ST), IGF-I, and IGF-binding proteins (BP) in growing beef cattle supplemented with bovine (b) ST. In each of two consecutive years, 40 growing beef cattle were blocked by weight (average BW: yr 1 = 316 kg, yr 2 = 305 kg) and used in a 2 x 2 factorial arrangement with main effects of bST (0 or 33 microg x kg BW(-1) x d(-1)) and level of feed intake (ad libitum [AL] or 0.75 AL). Relative to uninjected cattle, treatment with bST increased ADG 9.6% (1.14 vs 1.25 kg/d; P < 0.05) and increased G:F 8.1% (12.3 vs 13.3 gain [g]:feed [kg]; P < 0.05), whereas ADG in AL animals was 39% greater than that in 0.75 AL animals (1.39 vs 1.00 kg/d; P < 0.05). There was a tendency (P = 0.10) for a bST x level of feeding interaction, such that the increase in ADG with bST was greater in AL cattle than in 0.75 AL cattle (10.6 vs 7.8%; P = 0.10). Serum concentrations of ST were greater in 0.75 AL cattle than in AL cattle (13.0 vs 8.6 ng/mL; P < 0.05) and in bST-treated cattle than in uninjected cattle (16.3 vs 5.2 ng/mL; P < 0.05). Due to a bST x level of feeding interaction (P < 0.01), the magnitude of the increase in serum ST to exogenous bST was greater (P < 0.01) in 0.75 AL cattle than in AL cattle. Relative to uninjected cattle, treatment with bST increased (P < 0.05) serum concentrations of IGF-I and IGFBP-3 and reduced (P < 0.05) concentrations of IGFBP-2. Similarly, AL cattle had greater (P < 0.05) serum concentrations of IGF-I and IGFBP-3 and reduced (P < 0.05) IGFBP-2 compared with 0.75 AL cattle. In summary, treatment with bST increased growth rate and G:F and stimulated serum IGF-I and IGFBP-3 while reducing IGFBP-2. Feeding at 0.75 ad libitum intake reduced the magnitude of response for each of these variables. Thus, limit-feeding may reduce the effect of exogenous bST on growth rate by blunting bST-induced increases in IGF-I and IGFBP-3 and bST-induced decreases in IGFBP-2.     

Impact of heating-degree-day accumulation during bermudagrass hay storage on nutrient utilization by lambs.

Spontaneous heating in stored alfalfa (Medicago sativa) has reduced forage quality and DM and N digestibility through microbial respiration and Maillard polymer formation. The impact of heating-degree-day (HDD) accumulation in stored bermudagrass (Cynodon dactylon [L.] Pers.) was evaluated for its effect on nutrient utilization by lambs. Twenty Rambouillet wether lambs (53.1 +/- 0.74 kg) were used in a completely randomized total collection experiment. The hays selected for this study had previously undergone spontaneous heating, producing either 5, 119, 201, 273, or 401 HDD (> 35 degrees C) during a 60-d storage period. Lambs were offered diets of these hays at 1.5% of BW. Dry matter intake did not differ (P = 0.59) among hays. Linear relationships were detected between HDD and apparent digestibilities of DM (y = 59.1 - 0.016x; P < 0.01; R2 = 0.37), OM (y = 59.3 - 0.017x; P < 0.01; R2 = 0.43), NDF (y = 66.4 - 0.012x; P = 0.01; R2 = 0.30), and hemicellulose (y = 74.0 - 0.012x; P = 0.02; R2 = 0.27). Similarly, significant regressions were observed for fecal N excretion (g/d; y = 4.70 + 0.004x; P < 0.01; R2 = 0.68), apparent N absorbed (g/d; y = 7.4 - 0.005x; P < 0.01; R2 = 0.50), apparent N absorption (%; y = 61.2 - 0.038x; P < 0.01; R2 = 0.71), apparent neutral detergent insoluble nitrogen digestibility (%; y = 85.8 - 0.026x; P = 0.01; R2 = 0.73), and apparent acid detergent insoluble nitrogen digestibility (%; y = 1.5 + 0.101x; P < 0.01; R2 = 0.62). Therefore, spontaneous heating during the storage of bermudagrass hay has a negative effect on dry matter and fiber digestion and nitrogen absorption by lambs.     

Relationship of serum total calcium to serum albumin in dogs, cats, horses and cattle

A retrospective study was performed in order to assess the relationship between serum calcium and serum albumin concentrations in domestic animals. Results of 9041 canine, 1564 feline, 2917 equine, and 613 bovine serum samples from hospitalized patients were examined by regression analysis. Subpopulations of cases with concurrent elevations in creatinine or that were less than six months of age were evaluated separately. Statistically significant linear relationships between calcium and albumin concentrations were established for each species (p <0.05). The coefficients of determination (r²) were 0.169 for dogs, 0.294 for cats, 0.222 for horses, and 0.032 for cattle. The correlation coefficients (r) computed were: dogs = 0.411, cats = 0.543, horses = 0.471, cattle = 0.182. Neither increases in creatinine concentration nor juvenile age appreciably influenced the relationship between calcium and albumin concentrations. Interspecies variation was marked, and a strong correlation between calcium and albumin concentrations was not established in any species.     

Analysis of bovine udder, plate and viscera using near infrared reflectance spectroscopy

The objective of this study was to evaluate near infrared reflectance spectroscopy (NIRS) as an accurate and inexpensive alternative to conventional chemical analyses of nonconsumer bovine tissue. Udder, plate and visceral samples were collected from mature, Charolais-Angus and Hereford-Angus crossbred beef cows at slaughter, ground and analyzed for concentrations of lipid, protein and dry matter using standard AOAC chemical procedures. Samples were analyzed using NIRS. The collection of samples was randomly split into separate calibration and validation sets. Nine calibration equations representing each constituent and tissue combination were developed, using first- or second-order derivative mathematical transformations, and those calibration equations were validated. Correlation coefficients of calibration (R) and validation (r) ranged from .95 to .98 and from .87 to .97, respectively, for all analyses except plate dry matter (r = .77). Standard errors of calibration and prediction ranged from 1.89 to 5.81%. Results from this study are interpreted to indicate that bovine udder, plate and visceral tissue composition can be accurately, quickly and efficiently predicted using NIRS technology.     

Evaluation of average daily gain prediction by level one of the 1996 National Research Council beef model and development of net energy adjusters

Two data sets were developed to evaluate and refine feed energy predictions with the beef National Research Council (NRC, 1996) model level 1. The first data set included pen means of group-fed cattle from 31 growing trials (201 observations) and 17 finishing trials (154 observations) representing over 7,700 animals fed outside in dirt lots. The second data set consisted of 15 studies with individually fed cattle (916 observations) fed in a barn. In each data set, actual ADG was compared with ADG predicted with the NRC model level 1, assuming thermoneutral environmental conditions. Next, the observed ADG (kg), TDN intake (kg/d), and TDN concentration (kg/kg of DM) were used to develop equations to adjust the level 1 predicted diet NEm and NEg (diet NE adjusters) to be applied to more accurately predict ADG. In both data sets, the NRC (1996) model level 1 inaccurately predicted ADG (P < 0.001 for slope = 1; intercept = 0 when observed ADG was regressed on predicted ADG). The following nonlinear relationships to adjust NE based on observed ADG, TDN intake, and TDN concentration were all significant (P < 0.001): NE adjuster = 0.7011 x 10(-0.8562 x ADG) + 0.8042, R2 = 0.325, s(y.x) = 0.136 kg; NE adjuster = 4.795 10(-0.3689 x TDN intake) + 0.8233, R2 x = 0.714, s(y.x) = 0.157 kg; and NE adjuster = 357 x 10(-5.449 x TDN concentration) + 0.8138, R2 = 0.754, s(y.x) = 0.127 kg. An NE adjuster < 1 indicates overprediction of ADG. The average NE adjustment required for the pen-fed finishing trials was 0.820, whereas the (P < 0.001) adjustment of 0.906 for individually fed cattle indicates that the pen-fed environment increased NE requirements. The use of these equations should improve ADG prediction by the NRC (1996) model level 1, although the equations reflect limitations of the data from which they were developed and are appropriate only over the range of the developmental data set. There is a need for independent evaluation of the ability of the equations to improve ADG prediction by the NRC (1996) model level 1.     

播种行距和灌水量对紫花苜蓿种子产量及其构成因素的影响

研究了播种行距和灌水量对甘农3号紫花苜蓿种子产量及其构成因素的影响。通过2年研究,得出以下结论,1)随着行距增大,株高下降,株高和种子产量呈负相关,R=-0.802*。2)行距和灌水量对种子产量及产量构成因素的影响不同。行距对种子产量、有效分枝数/m2、花序数/枝条、豆荚数/花序和籽粒数/豆荚的影响较大;灌水量对种子产量及其构成要素的影响均较小。3)种子产量构成因素中,豆荚数/花序(x3)与种子产量极显著正相关,R2=0.882**;籽粒数/豆荚(x4)、花序数/枝条(x2)与种子产量显著正相关,相关系数分别为0.803*和0.693*。种子产量的回归方程为:y=260.358 64.152x3 50.976x4 5.482x2。4)播种当年和生长第2年,行距为100cm、灌水量为900 m3/hm2时,有效分枝数/m2、花序数/枝条、豆荚数/花序、籽粒数/豆荚和种子产量均为最高。2年间的种子产量呈显著正相关,R2=0.801*,回归方程为:y=772.563 0.521 5x 0.009 8x2-2.0×10-5x3。     

Mineral concentrations of plasma and liver after injection with a trace mineral complex differ among Angus and Simmental cattle

To examine the effects of cattle breed on the clearance rate of an injectable mineral product, 10 Angus and 10 Simmental steers were blocked by breed and initial BW (332 ± 33 kg) and injected with either Multimin 90 (MM) or sterilized saline (CON) at a dose of 1 mL/45 kg BW. Multimin 90 contains 15 mg Cu/mL (as Cu disodium EDTA), 60 mg Zn/mL (as Zn disodium EDTA), 10 mg Mn/mL (as Mn disodium EDTA), and 5 mg Se/mL (as sodium selenite). Steers received a corn-silage-based diet, and inorganic sources of Cu, Zn, Mn, and Se were supplemented at NRC recommended amounts. Jugular blood was collected immediately before injection and at 8 and 10 h post-injection and on days 1, 8, and 15 post-injection. Liver biopsies were collected 3 d before injection and on days 1, 8, and 15 post-injection. Liver and plasma mineral concentration and glutathione peroxidase (GSH-Px) activity data were analyzed as repeated measures. Plasma concentrations of Zn, Mn, and Se were greater (P = 0.01) and Cu tended to be greater (P = 0.12) post-injection in MM steers compared with the CON steers. Regardless of treatment, Simmental cattle had lower plasma concentrations of Cu, Zn, and Se (P ≤ 0.05) when compared with Angus cattle. Erythrocyte GSH-Px activity was greater (P = 0.01) in MM steers compared with CON steers. Liver concentrations of Cu, Zn, and Se were greater (P = 0.05) in MM steers compared with CON steers post-injection. Liver Mn concentrations tended to be greater (P = 0.06) in MM steers compared with CON steers in the days post-injection. Interestingly, Simmental cattle exhibited greater (P = 0.01) liver Mn concentrations in the days after injection compared with Angus cattle (7.0 and 6.0 mg Mn/kg for Simmental and Angus cattle, respectively), regardless of treatment. It is unclear if this breed difference is biologically relevant; however, these data may suggest that differences in liver excretion of Mn exist between the two breeds. Overall, use of an injectable trace mineral increased liver concentrations of Cu and Se through the 15-d sampling period, suggesting that this injectable mineral is an adequate way to improve Cu and Se status of cattle through at least 15 d.