Samples taken from three commercial runs of nodular cast iron, obtained from the same base metal, same nodularizing alloy, but different inoculants were studied. The percentages by weight of ...inoculant and nodularizing alloy were, respectively, 1.0% and 1.3%. In this way the nucleation and the growth of graphite nodules were studied by microstructural analysis using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). In this way, we observed that the growth sequence of the graphite nodules was associated to the formation of complex silicates rich in aluminum, calcium and barium around the graphite cores, generating an interface favorable to the heterogeneous graphite solidification from these particles of size larger than critical radius. Therefore, the race 1 sample inoculated with FeSi75% presented the lowest amount of nodules/mm2 and, consequently, less elongation, since there is a direct relation between the elongation and the number of nodules/mm2.
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•Performance of 3 different inoculants in the formation of graphite.•Evaluation of the sizes of the particles and quantities according to the inoculants.•Relation amount of graphite nodules with elongation.•MEV of graphite nodules with adequate scale.
Loss of pregnancy can occur at many different stages of gestation and for a variety of causes but clearly produces a negative impact for reproductive and economic performances of dairy herds. This ...review describes four pivotal periods for pregnancy loss during the first trimester of gestation and discusses possible causes for pregnancy failure during these periods. The first period occurs during the first week after breeding with lack of fertilization and death of the early embryo producing major losses in pregnancy, particularly under specific environmental and hormonal conditions. In general, 20%–50% of high-producing lactating dairy cows have already experienced pregnancy loss during the first week of gestation with methods to decrease pregnancy loss during this period targeting improved oocyte quality by alleviating heat stress, inflammatory diseases, and body condition loss, and by increasing progesterone concentrations during preovulatory follicle development. The second pivotal period, from Days 8 to 27, encompasses embryo elongation and the classical “maternal recognition of pregnancy” period with losses averaging ∼30% but with surprising variation between farms (25%–41%). Maintenance of the CL of pregnancy is produced by the embryonic signal interferon-tau and alteration in uterine secretory patterns of prostaglandins F2α, E1, and E2. Failures or delays in trophoblast elongation and/or embryonic development result in loss of pregnancy during the second pivotal period possibly due to suboptimal histotroph. The third pivotal period is during the second month of pregnancy, Days 28 to 60, with losses of ∼12% based on a summary of published results from more than 20,000 pregnancies in high-producing dairy cows. Delays or defects in development of the chorioallantoic placentomes or embryo result in CL regression or embryo death during this pivotal period. Finally, a fourth period during the third month of pregnancy has reduced pregnancy losses (∼2%), compared with the first three periods but can be elevated in some cows, particularly in those carrying twins in the same uterine horn. Thus, there are varied causes for pregnancy losses during each pivotal period that correspond to key physiological changes in the embryo, uterine environment, and ovary. Similarly, strategies to reduce these losses are likely to require a multifaceted approach using rational methods that target the critical physiology in each pivotal period.
Reproductive efficiency is closely tied to the profitability of dairy herds, and therefore successful dairy operations seek to achieve high 21-day pregnancy rates in order to reduce the calving ...interval and days in milk of the herd. There are various factors that impact reproductive performance, including the specific reproductive management program, body condition score loss and nutritional management, genetics of the cows, and the cow comfort provided by the facilities and management programs. To achieve high 21-day pregnancy rates, the service rate and pregnancy per artificial insemination (P/AI) should be increased. Currently, there are adjustments in timed artificial insemination (TAI) protocols and use of presynchronization programs that can increase P/AI, even to the point that fertility is higher with some TAI programs as compared with AI after standing estrus. Implementation of a systematic reproductive management program that utilizes efficient TAI programs with optimized management strategies can produce high reproductive indexes combined with healthy cows having high milk production termed "the high fertility cycle". The scientific results that underlie these concepts are presented in this manuscript along with how these ideas can be practically implemented to improve reproductive efficiency on commercial dairy operations.
Supplementing minerals beyond dietary requirements can increase the risk of toxicity and mineral excretion, making the selection of more bioavailable sources crucial. Thus, this work aimed to use ...metalloproteomics tools to investigate possible alterations in the hepatic proteome of broilers fed with diets containing two sources (sulfate and hydroxychloride) and two levels of copper (15 and 150 ppm) and manganese (80 and 120 ppm), totaling four treatments: low Cu/Mn SO
, high Cu/Mn SO
, low Cu/Mn (OH)Cl and high Cu/Mn (OH)Cl. The difference in abundance of protein spots and copper and manganese concentrations in liver and protein pellets were analyzed by analysis of variance with significance level of 5%. The Cu and Mn concentrations determined in liver and protein pellets suggested greater bioavailability of hydroxychloride sources. We identified 19 Cu-associated proteins spots, 10 Mn-associated protein spots, and 5 Cu and/or Mn-associated protein spots simultaneously. The analysis also indicated the induction of heat shock proteins and detoxification proteins in broilers fed with high levels of copper and manganese, suggesting the involvement of these proteins in metal tolerance and stress.
The aim of the present study was to evaluate the differential expression of plasma proteins in broiler chickens supplemented with different sources (sulfates and hydroxychlorides) and levels of ...copper (15 and 150 mg kg
) and manganese (80 and 120 mg kg
). For this, plasma samples from 40 broiler chickens were used, divided into four experimental groups: S15-80 (15 ppm CuSO
and 80 ppm MnSO
), S150-120 (150 ppm CuSO
and 120 ppm MnSO
), H15-80 (15 ppm Cu(OH)Cl and 80 ppm Mn(OH)Cl), and H150-120 (150 ppm Cu(OH)Cl and 120 ppm Mn(OH)Cl). From plasma samples obtained from each bird from the same treatment, four pools were made considering 10 birds per group. Plasma proteome fractionation was performed by 2D-PAGE. Concentrations of the studied minerals were also evaluated in both plasma and protein pellet samples. A higher concentration of Cu and Mn was observed in the plasma and protein pellets of groups that received higher mineral supplementation levels compared to those receiving lower levels. Mn concentrations were higher in plasma and protein pellets of the hydroxychloride-supplemented groups than the sulfate-supplemented groups. Analysis of the gels revealed a total of 40 differentially expressed spots among the four treatments. Supplementation with different sources of minerals, particularly at higher levels, resulted in changes in protein regulation, suggesting a potential imbalance in homeostasis.
Heat stress (HS) adversely influences productivity and welfare of dairy cattle. We hypothesized that the thermoregulatory mechanisms vary depending on the exposure time to HS, with a cumulative ...effect on the adaptive responses and thermal strain of the cow. To identify the effect of HS on adaptive thermoregulatory mechanisms and predictors of caloric balance, Holstein cows were housed in climate chambers and randomly distributed into thermoneutral (TN; n=12) or HS (n=12) treatments for 16 days. Vaginal temperature (VT), rectal temperature (Tre), respiratory rate (RR), heart rate (HR), and dry matter intake (DMI) were measured. The temperature and humidity under TN were 25.9±0.2°C and 73.0±0.8%, respectively, and under HS were 36.3±0.3°C and 60.9±0.9%, respectively. The RR of the HS cows increased immediately after exposure to heat and was higher (76.02±1.70bpm, p<0.001) than in the TN (39.70±0.71bpm). An increase in Tre (39.87±0.07°C in the HS vs. 38.56±0.03°C in the TN, p<0.001) and in VT (39.82±0.10°C in the HS vs. 38.26±0.03°C in the TN, p<0.001) followed the increase in RR. A decrease (p<0.05) in HR occurred in the HS (62.13±0.99bpm) compared with the TN (66.23±0.79bpm); however, the magnitude of the differences was not the same over time. The DMI was lower in HS cows from the third day (8.27±0.33kgd−1 in the HS vs. 14.03±0.29kgd−1 in the TN, p<0.001), and the reduction of DMI was strongly affected (r=−0.65) by changes in the temperature humidity index. The effect of environmental variables from the previous day on physiological parameters and DMI was more important than the immediate effect, and ambient temperature represented the most determinant factor for heat exchange. The difference in the responses to acute and chronic exposure to HS suggests an adaptive response. Thus, intense thermal stress strongly influence thermoregulatory mechanisms and the acclimation process depend critically on heat exposure time.
•Continuous and intense heat stress strongly influenced thermoregulatory mechanisms.•Body temperature and respiratory rate best reflect the responses of heat stressed cows.•Heart rate decreases in heat stressed cows and suggests an adaptive mechanism.•The climate variables have a lag effect on physiological responses and food intake.•The heat exposure time is essential for the acclimation process.
Maintenance of the corpus luteum (CL) beyond the time of luteolysis is essential for establishing pregnancy. Identifying the distinct features of early pregnancy CL remains unresolved, hence we ...analyzed here the transcriptome of CL on day 18 pregnant (P) and non-pregnant (NP) cows using RNA-Seq. CL of P cows expressed ISGs, verifying exposure to the pregnancy recognition signal, interferon-tau (IFNT), whereas the CL of NP cows had elevated luteal progesterone levels, implying that luteolysis had not yet commenced. The DEGs, IPA, and metascape canonical pathways, along with GSEA analysis, differed markedly in the CL of P cows from those of NP cows, at the same day of the cycle. Both metascape and IPA identified similar significantly enriched pathways such as interferon alpha/beta, sonic hedgehog pathway, TNFA, EDN1, TGFB1, and PDGF. However, type-1 interferon and sonic hedgehog pathways were positively enriched whereas most of the enriched pathways were downregulated in the P compared to NP samples. Thirty-four % of these pathways are known to be elevated by PGF2A during luteolysis. Notably, selective DEGs in luteinized granulosa cells were modulated by IFNT in vitro in a similar manner to their regulation in the CL of P cows. This study unraveled the unique transcriptomic signature of the IFNT-exposed, early pregnancy CL, highlighting the abundance of downregulated pathways known to be otherwise induced during luteolysis. These and IFNT-regulated in vitro pregnancy-specific DEGs suggest that IFNT contributes to the characteristics and maintenance of early pregnancy CL.
This manuscript focuses on potential changes in reproductive physiology that occur due to high milk production in lactating dairy cows. Four reproductive measures are discussed: interval to first ...ovulation, conception rate, duration of estrus, and multiple ovulation rate. The last two responses have now been closely linked to level of milk production. In contrast, time to first ovulation does not appear to be associated with level of milk production, and the association of conception rate with level of milk production is still controversial. In an attempt to explain some of the changes in reproductive physiology caused by high milk production a model of elevated steroid metabolism in lactating dairy cows is presented. Although many aspects of this model remain to be tested, a central role for elevated steroid metabolism in lactation-induced reproductive changes seems likely.
For most applications, martensitic stainless steels are subject to operating conditions where good mechanical properties and wear resistance are required. Soldering soft martensitic stainless steels ...features decreased tenacity of the welded joint which, along with the residual stresses, can shorten the life of component and accelerate the cavitation process. In order to increase the strength of the martensitic structures, thermal spraying is used to produce coatings, laid without resulting in thermal cycles that influence the structural integrity of the coated steels. This work was deposited by the electric arc and wire flame, the 410NiMo martensitic stainless steel, in wire and rod form, respectively, on the substrate of the martensitic stainless steel CA6NM. The samples were sent to Vickers microhardness tests and accelerated cavitation, according to ASTM G32-10. The results were obtained through optical microscopy, X-ray diffraction, SEM, and dispersive energy spectroscopy (DES); the samples featured high adhesion, low porosity, and cavitation erosion–resistant coatings. The thermal spray is suitable for the application of this type of coating.
This study was conducted to evaluate the effects of different levels and sources of Cu and Mn (sulfate or hydroxychloride - H) on growth performance, carcass traits, meat and skin quality, footpad ...dermatitis severity, litter quality, liver and plasma mineral content, and ileal mineral absorption. A total of 1,920 one-day-old male Cobb 500 broiler chicks were assigned randomly to one of 2 × 3+2 factorially arranged treatments: CuH (15 and 150 ppm) × MnH (40, 80, 120 ppm) + 15 ppm Cu Sulfate with 80 ppm Mn Sulfate (control 1) or 150 ppm Cu Sulfate with 120 ppm Mn sulfate (control 2) for 42 d. Each treatment consisted of 8 replicates of 30 birds. At 42-day-old were slaughtered for carcass yield and meat quality analyses. At 43-day-old, it was determined the apparent ileal absorption of minerals and the concentration of Cu and Mn in the liver and plasma. The resistance and elasticity of the skin, and footpad dermatitis severity were also evaluated. The level 150 ppm CuH improved the FCR compared to the 15 ppm CuH and 15 ppm Cu Sulfate level. Broilers fed diets containing 150 ppm CuH showed higher breast yield compared to those fed diets containing 15 ppm. Breast yield was positively influenced by the inclusion of 40 ppm MnH. There was an interaction between the CuH and the MnH for skin elasticity, and the highest elasticity was found when the supplementation levels were 150 ppm CuH and 40 ppm MnH. High levels of copper decreased the incidence of footpad dermatitis. The hydroxychloride source determined a higher mineral concentration in the liver and plasma and greater apparent ileal absorption of Cu and Mn. In conclusion, dietary supplementation with 150 ppm CuH and 40 or 80 ppm MnH enhance breast yield and improves skin resistance. The inclusion of 150 ppm CuH has the possibility to improve the FCR and decrease leg injuries. Furthermore, the hydroxychloride source seems to be more bioavailable than the sulfate source.
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