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31.
Henryk A. Sobczuk Rudolf Plagge Ryszard T. Walczak Christian H. Roth 《植物养料与土壤学杂志》1992,155(2):157-163
Laboratory equipment was developed to measure nonsteady water potential and water content profiles in soil columns, with a high resolution in time and space. Moisture content was monitored using TDR-miniprobes and water potential was measured with microtensiometers. Gradients were applied by controlling the water potential at the bottom of the soil column during adsorption and desorption with the aid of a ceramic plate. The described experimental setup was designed specifically to determine effects of hysteresis on the water content/water potential and water potential/hydraulic conductivity relationships in undisturbed soil samples. In addition, an algorithm to process the data and to calculate the above mentioned relationships is presented. The algorithm includes the smoothing of data with Bezier functions before the calculation of the moisture retention curves and the conductivity functions. Results obtained from an albic E-horizon of a silty Luvisol are presented exemplarily to demonstrate the applicability of the proposed method in studying hysteresis effects. 相似文献
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van der Peet-Schwering CM Kemp B Plagge JG Vereijken PF den Hartog LA Spoolder HA Verstegen MW 《Journal of animal science》2004,82(4):1246-1257
The objective of this experiment was to study the effects of feeding group-housed gestating sows a diet with a high level of fermentable nonstarch polysaccharides (NSP; approximately 45% sugar beet pulp as fed) ad libitum on the development in individual feed intake characteristics and reproductive performance during three successive reproduction cycles. Performance of the ad libitum-fed sows was compared to the performance of sows that were fed a conventional diet restrictedly. Feed intake characteristics during gestation were only measured in the ad libitum-fed sows. One hundred and nineteen sows were assigned to one of two gestation feeding regimens. Gestating sows were fed a conventional Dutch diet restrictedly or a diet with a high level of fermentable NSP ad libitum. During lactation, sows were given free access to a commercial lactation diet from d 6 after parturition onward. The ad libitum-fed sows ate 1.3 kg/d more during gestation than the restrictedly fed sows (P < 0.001), resulting in higher body weight and backfat gains during gestation (P < 0.05). Sows that were fed ad libitum during gestation lost more body weight and backfat during lactation (P < 0.001) than sows that were fed restrictedly during gestation. Feed intake during lactation, however, did not differ between sows that were fed restrictedly or ad libitum during gestation. The numbers of total piglets born, live-born and stillborn piglets, piglet birth weight, weaning-to-estrus interval, and percentage of sows that returned to estrus after first insemination were not affected by gestation feeding regimen. Mean daily voluntary feed intake (as-fed basis) over the three reproduction cycles in the ad libitum-fed gestating sows was 4.2 kg/d. Depending on the number of preceding reproduction cycles during which a sow was fed ad libitum, the maximum voluntary feed intake was reached in Parity 3, 4, or 5 and then remained stable in subsequent parities. Mean daily feed intake of the ad libitum-fed sows increased from wk 2 to 6 of gestation and then decreased to wk 15 of gestation. The mean number of daily visits with feed intake over the three reproduction cycles was 13.8. On average, ad libitum-fed sows spent 90 min/d on eating. This study shows that it is possible to feed gestating sows a diet with a high level of fermentable NSP ad libitum during three successive reproduction cycles without negative effects on reproductive performance. 相似文献
33.
L Cattaneo ML Signorini J Bertoli JA Bartolomé NC Gareis PU Díaz GA Bó HH Ortega 《Reproduction in domestic animals》2014,49(6):1028-1033
To describe the epidemiology of cystic ovarian disease (COD), to find possible risk factors associated with the incidence of cysts and to analyse the impact of COD on the reproductive performance of dairy cows, databases from 22 dairy herds from the main dairy region in Argentina were retrospectively evaluated throughout a 3‐year period (2009–2011). A total of 248 COD cases over 9156 parturitions were recorded, resulting in a cumulative incidence rate of 2.7%. Cystic ovarian disease incidence density was lower during the first 100 days post‐partum (DPP) than during later stages of lactation. Seasonality had a significant influence on the disease presentation with higher incidence rates during winter and spring. Cows with a previous diagnosis of clinical mastitis showed 2.72 times more chances of developing ovarian cysts. Cystic cows had longer calving to first service and calving to conception intervals and lower conception rate than controls. 相似文献
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