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71.
Benefits of feeding pharmacological concentrations of zinc (Zn) provided by Zn oxide (ZnO) to 21-d conventionally weaned pigs in the nursery have been documented; however, several management questions remain. We conducted two experiments to evaluate the effect on growth from feeding 3,000 ppm Zn as ZnO during different weeks of the nursery period. In Exp. 1 (n = 138, 11.5 d of age, 3.8 kg BW) and Exp. 2 (n = 246, 24.5 d of age, 7.2 kg BW), pigs were fed either basal diets containing 100 ppm supplemental Zn (adequate) or the same diet with an additional 3,000 ppm Zn (high) supplied as ZnO. Pigs were fed four or two dietary phases in Exp. 1 and 2, respectively, that changed in dietary ingredients and nutrient content (lysine and crude protein) to meet the changing physiological needs of the pigs for the 28-d nursery period. Dietary Zn treatments were 1) adequate Zn fed wk 1 to 4, 2) high Zn fed wk 1, 3) high Zn fed wk 2, 4) high Zn fed wk 1 and 2, 5) high Zn fed wk 2 and 3, and 6) high Zn fed wk 1 to 4. In Exp. 1 and 2, pigs fed high Zn for wk 1 and 2 or the entire 28-d nursery period had the greatest (P < .05) ADG. During any week, pigs fed high Zn had greater concentrations of hepatic metallothionein and Zn in plasma, liver, and kidney than those pigs fed adequate Zn (P < .05). In summary, both early- and traditionally weaned pigs need to be fed pharmacological concentrations of Zn provided as ZnO for a minimum of 2 wk immediately after weaning to enhance growth. 相似文献
72.
Otolith chemistry indicates walleye movement and entrainment in a large serial reservoir system 下载免费PDF全文
Understanding fish movement in impounded river systems is important for fisheries management. Otolith chemistry was used to examine walleye Sander vitreus (Mitchill) intra‐ and inter‐reservoir movement in four Missouri River impoundments. Age‐0 individuals were reclassified with 75%–93% accuracy to known natal sites, allowing for reliable evaluation of movement patterns of age‐1 and older fish. Nearly half of walleye occupied the same location annually (i.e. site residency) between 2009 and 2010. In 2011, during the largest flood on record since 1898, downstream movement (49% of age‐1 and older fish) exceeded upstream movement (7%) and site residency (33%) across the study area. After the flood, most walleye moved downstream within reservoirs (45%) or were site residents (37%). Entrainment occurred most frequently during the flood year and was proportionally greatest in downstream reservoirs. Otolith chemistry is useful for understanding walleye movement and entrainment and is a tool for fisheries management with applications such as informing reservoir water releases, harvest regulations and habitat protection and rehabilitation within and outside the Missouri River reservoir system. 相似文献
73.
74.
Objective To determine the prevalence of mastitis pathogens in high‐producing intensive dairy herds in New South Wales. Design Field survey. Procedure Milk samples from the mastitis‐affected quarter were collected from cows on five high‐producing dairy farms in NSW. The 820 samples were cultured using standard microbiological culture techniques. Results Bacteria or fungi were isolated from 83.3% of samples (683/820). More than two colony types were isolated from 16.7% of samples (137/820), two types from 6.6% (54/820), and one type from 52.3% (429/820). No bacteria were isolated from 24.4% (200/820) of the primary cultures, but enrichment cultures of these samples yielded single colony type bacterial isolates from 36.5% (73/200) of samples. Environmental pathogens, including coliforms, environmental Streptococcus and Staphylococcus spp., made up 91% (555/610) of isolates and accounted for 33.6% (205/610), 41.6% (254/610) and 15.7% (96/610), respectively, of isolates. Escherichia coli accounted for 76.1% (156/205) of the coliform isolates, Streptococcus uberis and Streptococcus dysgalactiae accounted for 32.3% (82/254) and 28.0% (71/254), respectively, of the environmental streptococcal isolates. Contagious pathogens were uncommon, comprising only 2.5% (15/610) of the total isolates. Conclusion The incidence and causes of mastitis are largely influenced by farm management. The relatively high prevalence of coliform mastitis in the intensive high‐producing herds in this survey contrasts with the low incidence reported in surveys of pasture‐based herds in Victoria. If the Australian dairy industry continues its current trend of intensification, coliform intra‐mammary infections may emerge as an increasingly important cause of mastitis. 相似文献
75.
Surgical resection of a dysgerminoma in a mare 总被引:1,自引:1,他引:0
A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematology and serum biochemistry results were within normal limits. The mare was initially treated conservatively with antibiotics, but the mass continued to increase in size, so it was surgically excised. The mass involved the left ovary. The mare showed transient abdominal pain after surgery, but developed no other complications and was in foal 7 months later. On histology, the mass was diagnosed as a dysgerminoma, a rare ovarian tumour of germ cell origin. 相似文献
76.
77.
Carlson JC Linz GM Ballweber LR Elmore SA Pettit SE Franklin AB 《Veterinary parasitology》2011,180(3-4):340-343
To investigate the relationship between European starlings and bovine coccidiosis we collected samples from European starlings, cattle feed bunks, cattle water troughs, and cattle feces within concentrated animal feeding operations (CAFOs). These samples were screened for coccidia spp. to investigate (i) the prevalence of coccidia in starlings using CAFOs; (ii) if there is a relationship between bovine coccidiosis and starling numbers; (iii) if coccidia contamination of cattle feed and water is related to the number of starlings observed on CAFOs. Coccidia belonging to the genus Eimeria were detected in cattle feces and one water sample but no Eimeria spp. were detected in European starlings or cattle feed. However, many European starling samples were positive for Isospora. Starling use of CAFOs did not appear to be associated with coccidia spp. shedding by cattle and there was no correlation between starling numbers and contamination of cattle feed and water, suggesting that starling do not contribute to the amplification and spread of Eimeria in CAFOs. 相似文献
78.
Francisco Mamani-Pati David E. Clay Gregg Carlson Sharon A. Clay 《Journal of plant nutrition》2013,36(9):1278-1289
To prepare for a carbon (C) constrained economy, crop production energy audits or life cycle analysis (LCA) must be conducted. However, energy audits may not maximize profitability. This study conducted simultaneous production, economic, and energy audits to evaluate differences among these assessments. The 2005 and 2006 South Dakota field experiment contained two nitrogen (N; 0 and 224 kg N ha?1) rates, two corn population levels (76,500 and 149,000 plants ha?1), and two simulated landscape positions (upper backslope and lower backslope). The energy inputs, outputs, and net energy gain for corn grain used in ethanol production were calculated using the Nebraska Biofuel Energy Simulator (BESS) version 2008.3.1. For LC analysis, corn grain was used in ethanol production and dry distiller's grain was used as a livestock feed. Manure was not applied to the field. A partial economic analysis to examine profitability was conducted where seed, N fertilizer, and corn values were $312 (100,000 seeds)?1, $1.25 (kg N)?1, and $158 (Mg grain at 15.5% moisture)?1, respectively. Results showed that: 1) to maximize profitability and energy gains, inputs must closely match crop needs for a site; 2) increasing the population level from 74,500 to 149,000 plants ha?1 increased energy input and output, increased yield and energy gain by 11%, but did not influence profitability; 3) increasing N from 0 to 224 kg N ha?1 increased yield 7%, reduced profit by $145/ha, increased energy input and output values, but did not impact energy gain; and 4) corn grown in high yielding areas of landscapes may have higher yields (P = 0.08), profitability (P = 0.08), and energy gains (P = 0.08) than other areas. These calculations demonstrate that yield, profitability, and energy audits may have divergent results. 相似文献
79.
Abstract Nutrient solution experiments were conducted in the growth chamber to study the influence of rootstock, solution Ca/Mg ratios and solution nickel on K uptake. The experimental plants were one‐year‐old prune trees: ‘French’ prune (Prunus domestica L.) scions grafted on Myrobalan 29C (P. cerasifera Ehrh.), Marianna 2624 (P. cerasifera x P. munsoniana?) or Nemaguard (P. persica x P. davidiana) rootstocks. Ion uptake parameters Imax, Km, and Cmin were calculated from ion depletion measurements over a 6 to 10‐hr period. With K solution concentrations initially adjusted to 100 μM, K uptake rates of Prunus rootstocks were constant down to approximately 20–30 μM, then declined. Rootstocks were able to deplete solution K to concentrations less than 1 μM. There were no significant differences in K uptake parameters among the rootstocks tested. Varying solution Ca/Mg ratio from 2.75/1 to 1/4 (Ca + Mg = 3.75 mM) had no effect on K uptake. Potassium uptake rates of Myrobalan 29C rootstocks in the presence of 100 μM nickel were not significantly different from those in the absence of nickel. Rates of nickel uptake were significantly lower than those of K. After eight days of pretreatment in solutions adjusted daily to 100 μM Ni(NO3)2, prune leaves began to show signs of interveinal chlorosis. Potassium uptake by nickel pretreated trees was not significantly different from that by control trees. Results are discussed in relation to field observations of K deficiency in prune orchards. 相似文献
80.
An inexpensive and mechanically simple technique has been developed to maintain realistically low P concentrations in nutrient solutions using a solid‐phase buffer. Phosphate is adsorbed on alumina in a PVC column, and the resulting alumina‐F is desorbed against nutrient solution circulated through the column. Kinetics of P adsorption and desorption indicate that the solid‐phase‐P has rapidly and slowly desorbing components and that buffering capacity is limited by desorption from the solid phase. The technique has been used to maintain F concentrations as low as 0.4 minol m‐3 for 26 days in experiments with maize (Zea mays L.), and in solution cultures with prune (Prunus domestica L.) trees. Effects of P supply on P accumulation and P transport are discussed. 相似文献