High resolution Fourier transform near IR solar spectra are used to estimate the column-averaged dry-air mole fraction (DMF) of CO 2 andCH4variations in the atmosphere. The preliminary retrieval results for CO 2 andCH4variations in the area of Hefei, China, are presented, and the underlying error sources are also analyzed. Both a forward analysis and an inversion algorithm are included in the retrieval. The forward analysis uses the modeled atmospheric transmittance to line-by-line (LBL) convolute the instrument line shape function. The influences of the temperature, pressure, humidity, and a priori gases are considered in the atmospheric transmittance model. The inversion algorithm is based on the nonlinear iterative and nonlinear least squares spectral fitting, which is used to obtainVCDCO2andVCDCH4(which represent vertical column density of CO 2 andCH4, resp.). Furthermore, theVCDO2is also retrieved for converting the VCDs into DMFs. DMFs are final products of data analysis. The inversion results can clearly resolve the tiny variations of CO 2 andCH4under strong atmospheric background. Spectral fitting residuals for bothVCDCO2andVCDCH4are less than 0.5%. Finally, CO 2 andCH4diurnal variations are investigated based on a typical observation. About 2 ppm amplitude forDMFCO2diurnal variations and less than 15 ppb amplitude forDMFCH4are observed.
The iron status of sows has a great influence on reproductive performance. Iron deficiency reduces reproductive performance and newborn piglet survival rate of sow. The hemoglobin is a potential predictor for the iron status of sows and is convenient for rapid detection in pig farms. However, the relationship between iron status, hemoglobin, placental trace elements, and reproductive performance remains unclear. In this study, the hemoglobin and reproductive performance of more than 500 sows with first to sixth parities at different gestation stages (25, 55, 75, 95, and 110 d of gestation) in two large-scale sow farms were collected, and the content of placental Fe, Zn, Mn, and Cu was analyzed. The results show that hemoglobin levels of sows during pregnancy (days 75, 95, and 110) decreased significantly (P < 0.001). As the parity increases, the hemoglobin levels of sows at days 25 and 55 of gestation and placental mineral element contents including Fe, Zn, Mn, and Cu at delivery decreased (P < 0.05), while the litter size, birth alive, and litter weights increased gradually (P < 0.001). Furthermore, hemoglobin during pregnancy had a negative linear correlation with litter weight and average weight (P < 0.05), and higher hemoglobin at day 25 of gestation may reduce the number of stillbirths (P = 0.05), but higher hemoglobin at day 110 of gestation may tend to be a benefit for the birth (P = 0.01). And there was a significant positive linear correlation between hemoglobin at day 110 of gestation and placental Fe and Mn levels (P = 0.002, P = 0.013). There was also a significant positive linear correlation among Fe, Zn, Mn, and Cu in the placenta (P < 0.001). The levels of Fe, Zn, and Mn in the placental at delivery were positively related to the average weight of the fetus (P = 0.048, P = 0.027, P = 0.047), and placental Cu was linearly correlated with litter size (P = 0.029). Our research revealed that the requirements for iron during gestation were varied in different gestation periods and parities. The feeds should be adjusted according to the gestation periods, parities, or iron status to meet the iron requirements of sows and fetal pigs.Iron deficiency and iron excess may cause adverse outcomes during pregnancy. In sows’ feed, iron is added as ferrous sulfate, ferrous glycine, or other forms to improve their reproductive performance and prevent iron-deficiency anemia in their offspring. However, it is always ineffective and iron-deficiency anemia often occurs in piglets. To explore the iron requirements in pregnant sows, we conducted a large-scale farm study to track the hemoglobin levels, placental trace element content, and reproductive performances of hundreds of sows. The correlation between the hemoglobin levels, placental trace element content, and reproductive performance indicators of sows during pregnancy at different parities was analyzed. We found that pregnancy hemoglobin level of sows decreases during the gestation and varies at different parities. The hemoglobin level of sows during pregnancy was linearly negatively correlated with reproductive performance. The content of iron, zinc, manganese, and copper in the placenta was linearly positively correlated. Our results revealed that iron deficiency or excess in sows’ feed may not be conducive to the improvement of reproductive performance, and the optimal iron supplementation dose during pregnancy may depend on the iron status and number of fetuses of sow.
Abstract Trace element additives are widely supplemented in animal feed to improve growth and reproductive performance, especially for pregnant sows. Although organic trace elements significantly improved production performance compared with inorganic form due to the better bioavailability, antioxidant and immune-promoting function, reports on comparison of the effects on different ligands is still limited. And it is not known that microelement methionine hydroxy analogue chelate (MHAC) whether has similar or even better bioavailability than amino acid chelate (AAC). Thus, the Zn, Cu and Mn chelated with methionine hydroxy analogue (Zn-, Cu- and Mn-MHAC) and amino acid chelate (AAC) were compared in two large-scaled farms under similar conditions. The results showed Zn-, Cu- and Mn-MHAC trace elements significantly increased reproductive performance of Landrace × Yorkshire (LY) 1st sows in treatment farm related to litter size and weight while reduced all adverse pregnancy outcomes ( P < 0.001) not only in partial application period but also in full application period compared with historical period, especially in live litter size ( P < 0.001), healthy litter size ( P < 0.001) and litter weight ( P < 0.001), and the increase of birth average weight more than 100g. Treatment farm has similar-level ( P > 0.05) even significantly better production performance included litter size ( P = 0.003), live litter size ( P = 0.039) and mummies ( P = 0.011) compared to the control farm in the end of trial period which was much worse than that of control farm in historical period ( P < 0.001). In addition, all production performance of treatment farm had a continuous upward trend while control farm showed instability and decreasing trend. Our research revealed Zn-, Cu- and Mn-MHAC may have better effect on improving the performance of sows compared to amino acid chelate (AAC).
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