Effects of feeding pomegranate seed pulp and coconut meal by-products on milk yield, milk quality, and metabolic responses of Awassi ewes and pre-weaning growth.

Background and Aim: Feeding by-products, such as pomegranate seed pulp (PSP) and coconut meal (COC), to livestock may enhance production efficiency and increase profits. This study aimed to evaluate the effects of PSP and COC on milk production, body weight change, metabolic response (Exp. 1), digestibility, and N balance (Exp. 2). Materials and Methods: Twenty-four ewes nursing single lambs were randomly assigned to one of three diets: Control (CON) (n = 8), 7.5% PSP (n = 8), and 7.5% COC (n = 8) of dry matter (DM). Every sheep was born 3-4 days before the start of the experiment. The 1st week of the experiment was devoted to diet adaptation, while the data were collected during the following 8 weeks (Exp. 1). Nine lambs were randomly assigned to one of the three diets for intensive data collection to evaluate the diet digestibility and animal nitrogen (N) balance (Exp. 2). The data were analyzed using the MIXED SAS procedures. Results: The PSP group consumed more DM, followed by the COC and CON groups. For lambs, the final BW, total gain, and average daily gain in the PSP group were greater (p < 0.05) than those in the COC and CON groups. The CON group had lower milk output, total solids, protein, fat, and lactose levels than the PSP and COC groups (p < 0.05). The cost of milk production was lower (p < 0.05) in the PSP and COC diet groups than in the CON group. Blood serum parameters were similar among the dietary groups, except for total cholesterol and high-density lipoprotein, which were higher in the COC group than in the CON group. No differences were observed in nutrient digestibility and N balance. Conclusion: Feeding PSP and COC to nursing ewes appears beneficial because it increases milk production and pre-weaning lamb growth and reduces milk production cost.

Optimizing nutrient solution for vegetative growth of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan through plant tissue nutrient balance estimation.

BACKGROUND: Orchids are grown without soil in many regions of the world, but there is a lack of studies to define the balanced and adequate nutrient solution for their cultivation, mainly in the vegetative growth phase. Therefore, this paper aims to evaluate the optimal concentration of the nutrient solution based on the proposal by Hoagland and Arnon (1950) in the vegetative growth phase capable of increasing the nutrient contents, growth, and dry matter production of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan. In addition, this paper aims to estimate a new nutrient solution from the optimal nutrient contents in the dry matter of these orchid species to be used in the vegetative growth phase. RESULTS: Nutrient contents, growth, and dry matter production increased as the nutrient solution concentration increased up to an average concentration of 62 and 77% for D. Tubtim Siam and P. Taisuco Swan, respectively. We found that the Hoagland and Arnon solution presented a group of nutrients with concentrations above the requirement for P. Taisuco Swan (nitrogen, phosphor, calcium, and sulfur) and D. Tubtim Siam (phosphor, calcium, magnesium, and sulfur), while other nutrients in the solution did not meet the nutritional demand of these orchid species, inducing nutritional imbalance in the vegetative growth phase. CONCLUSION: We conclude that using a balanced nutrient solution created specifically for each orchid species in vegetative growth might favor their sustainable cultivation by optimizing the use of nutrients in the growing medium.

Age-dependent effects of metformin on human oligodendrocyte lineage cell ensheathment capacity.

Metformin restores the myelination potential of aged rat A2B5+ oligodendrocyte progenitor cells and may enhance recovery in children with post-radiation brain injury. Human late progenitor cells (O4+A2B5+) have a superior capacity to ensheath nanofibres compared to mature oligodendrocytes, with cells from paediatric sources exceeding adults. In this study, we assessed the effects of metformin on ensheathment capacity of human adult and paediatric progenitors and mature oligodendrocytes and related differences to transcriptional changes. A2B5+ progenitors and mature cells, derived from surgical tissues by immune-magnetic separation, were assessed for ensheathment capacity in nanofibre plates over 2 weeks. Metformin (10 µM every other day) was added to selected cultures. RNA was extracted from treated and control cultures after 2 days. For all ages, ensheathment by progenitors exceeded mature oligodendrocytes. Metformin enhanced ensheathment by adult donor cells but reduced ensheathment by paediatric cells. Metformin marginally increased cell death in paediatric progenitors. Metformin-induced changes in gene expression are distinct for each cell type. Adult progenitors showed up-regulation of pathways involved in the process of outgrowth and promoting lipid biosynthesis. Paediatric progenitors showed a relatively greater proportion of down- versus up-regulated pathways, these involved cell morphology, development and synaptic transmission. Metformin-induced AMP-activated protein kinase activation in all cell types; AMP-activated protein kinase inhibitor BML-275 reduced functional metformin effects only with adult cells. Our results indicate age and differentiation stage-related differences in human oligodendroglia lineage cells in response to metformin. Clinical trials for demyelinating conditions will indicate how these differences translate in vivo.

Regulation of stress granule formation in human oligodendrocytes.

Oligodendrocyte (OL) injury and subsequent loss is a pathologic hallmark of multiple sclerosis (MS). Stress granules (SGs) are membrane-less organelles containing mRNAs stalled in translation and considered as participants of the cellular response to stress. Here we show SGs in OLs in active and inactive areas of MS lesions as well as in normal-appearing white matter. In cultures of primary human adult brain derived OLs, metabolic stress conditions induce transient SG formation in these cells. Combining pro-inflammatory cytokines, which alone do not induce SG formation, with metabolic stress results in persistence of SGs. Unlike sodium arsenite, metabolic stress induced SG formation is not blocked by the integrated stress response inhibitor. Glycolytic inhibition also induces persistent SGs indicating the dependence of SG formation and disassembly on the energetic glycolytic properties of human OLs. We conclude that SG persistence in OLs in MS reflects their response to a combination of metabolic stress and pro-inflammatory conditions.

The Anti-Müllerian Hormone as Endocrine and Molecular Marker Associated with Reproductive Performance in Holstein Dairy Cows Exposed to Heat Stress.

Anti-Müllerian hormone (AMH) is proposed as a biomarker for fertility in cattle, yet this associative relationship appears to be influenced by heat stress (HS). The objective was to test serum AMH and AMH-related single nucleotide polymorphisms (SNPs) as markers potentially predictive of reproductive traits in dairy cows experiencing HS. The study included 300 Holstein cows that were genotyped using BovineSNP50 (54,000 SNP). A genome-wide association study was then executed. Nine intragenic SNPs within the pathways that influence the AMH gene were found important with multiple comparisons adjustment tests (p < 1.09 × 10-6). A further validation study was performed in an independent Holstein cattle population, which was divided into moderate (MH; n = 152) and severe heat-stressed (SH; n = 128) groups and then subjected to a summer reproductive management program. Serum AMH was confirmed as a predictor of fertility measures (p < 0.05) in MH but not in the SH group. Cows were genotyped, which revealed four SNPs as predictive markers for serum AMH (p < 0.01), reproductive traits (p < 0.01), and additional physiological variables (p < 0.05). These SNPs were in the genes AMH, IGFBP1, LGR5, and TLR4. In conclusion, serum AMH concentrations and AMH polymorphisms are proposed as predictive markers that can be used in conjunction with genomic breeding value approaches to improve reproductive performance in Holstein cows exposed to summer HS conditions.

Growth Performance, Blood Metabolites and Carcass Characteristics of Black Goat Kids Fed Diets Containing Olive Cake.

This study investigated the dietary effect of incorporating different levels of olive cake (OC) on the metabolic responses, growth performance, and carcass characteristics of black goat male kids. Thirty kids (body weight = 17.3 ± 0.40 kg) were randomly distributed into one of three equally sized dietary groups: a control diet (CON), OC at 75 g/kg (OC75), and OC at 150 g/kg (OC150) of dietary dry matter (DM). The results revealed that the intake of DM, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) was similar (p ≥ 0.11) among the three treatment groups. However, the OC150 group had the greatest (p < 0.0001) ether extract (EE) intake compared to the OC75 and CON groups. The growth measurements were similar (p ≥ 0.13) among the three groups. Feed efficiency was not affected by the inclusion of OC. In contrast to the CON diet, the cost of gain was, however, reduced (p = 0.004) in the OC diets. All three treatment groups' digestibility of DM, CP, and ADF was similar. However, when compared to the OC75 and CON groups, the digestibility of NDF was better (p < 0.05) in the OC150 group. The N intake did not differ among the three experimental groups. Nitrogen retained as g/d was higher (p = 0.04) in the OC150 and OC75 groups compared to the CON group, while retention as a percentage (g/100 g) was similar among the three groups. Except for intermuscular fat, total fat, leg fat depth, and tissue depth, the inclusion of OC did not result in any discernible treatment effects on the carcass and meat quality parameters. Only alanine aminotransferase enzyme activity was lower (p < 0.0001) in OC-treated groups compared to the CON group. In summary, incorporating OC at 75 g/kg and 150 g/kg levels into the diets of black goat kids had positive comparable effects on some parameters related to growth performance, carcass attributes, and meat quality. Importantly, utilizing olive cake led to cost savings in production and may serve as a viable alternative feed source in goat nutrition.

Genetic parameters for pulmonary arterial pressure, yearling performance, and carcass ultrasound traits in Angus cattle.

Pulmonary arterial pressure (PAP) can be used as an indicator of susceptibility to pulmonary hypertension and subsequent potential to develop right-sided heart failure (RHF). Previously reported heritability estimates of PAP have been moderate to high. Based on these estimates, selection for the indicator trait, PAP, could reduce the incidence of RHF due to hypoxia. Previous studies have also speculated that increased growth rates and body fat accumulation contribute to increased PAP and RHF. Research evaluating the genetic relationships between PAP and performance traits (e.g., yearling weight and postweaning gain) has yielded conflicting results, leading to ambiguity and uncertainty regarding the underlying genetic relationships. Additionally, no previous research has evaluated the relationship between PAP and ultrasound carcass traits. Therefore, the objective of this study was to estimate trait heritabilities and genetic correlations between PAP, post-weaning growth traits, and ultrasound carcass traits in Angus cattle, using data (n = 4,511) from the American Angus Association. We hypothesized that traits associated with increased growth and muscle would have a positive genetic (i.e., unfavorable) relationship with PAP. Estimates for heritability and genetic correlations were obtained using a multi-trait animal model. Heritability estimates for PAP (0.21 ± 0.04), post-weaning gain (PWG; 0.31 ± 0.04), and yearling weight (YWT; 0.37 ± 0.04) were within the range of estimates previously reported. Genetic correlations were weak (< 0.20) between PAP, PWG, and YWT. A low-to-moderate genetic correlation between PAP and ultrasound ribeye area (UREA) was found (0.25 ± 0.12). Genetic correlations between PAP, ultrasound back fat (UBF), ultrasound intramuscular fat (IMF), and ultrasound rump fat (RUMP) were weak (ranging in magnitude from -0.05 to 0.10) and therefore, do not provide strong support for the hypothesis of an antagonistic relationship between PAP and carcass ultrasound traits, while heritability estimates for UBF (0.43 ± 0.05), UREA (0.31 ± 0.04), IMF (0.35 ± 0.04), and RUMP (0.47 ± 0.05) were in the range of previously reported values.

Beef cattle residing >1,500 m are subject to reduced atmospheric oxygen levels when compared with beef cattle at lower elevations which may result in hypoxia-induced pulmonary hypertension and right-side heart failure. Breeders use pulmonary arterial pressures to identify animals at risk of right-side heart failure and to select breeding animals that are less susceptible to the problem. There is a concern that selection for growth and carcass characteristics may be increasing the incidence of heart failure in feedlot cattle at elevations <1,500 m. To address the concern, this study estimated the genetic correlations (i.e., relationships) between pulmonary arterial pressure, growth, and ultrasound carcass measures in Angus cattle. The study shows that the genetic relationships between pulmonary arterial pressure and these traits are minimal to non-existent with the exception of ultrasound ribeye area. Our estimate suggests a moderate, unfavorable relationship between pulmonary arterial pressure and ribeye area and that single-trait selection for increased ribeye area alone may result in increased susceptibility to right-side heart failure. However, selection for both traits simultaneously should overcome increases in susceptibility given the moderate strength of the genetic relationship.

Genetic Markers Associated with Milk Production and Thermotolerance in Holstein Dairy Cows Managed in a Heat-Stressed Environment.

Dairy production in Holstein cows in a semiarid environment is challenging due to heat stress. Under such conditions, genetic selection for heat tolerance appears to be a useful strategy. The objective was to validate molecular markers associated with milk production and thermotolerance traits in Holstein cows managed in a hot and humid environment. Lactating cows (n = 300) exposed to a heat stress environment were genotyped using a medium-density array including 53,218 SNPs. A genome-wide association study (GWAS) detected six SNPs associated with total milk yield (MY305) that surpassed multiple testing (p < 1.14 × 10-6). These SNPs were further validated in 216 Holstein cows from two independent populations that were genotyped using the TaqMan bi-allelic discrimination method and qPCR. In these cows, only the SNPs rs8193046, rs43410971, and rs382039214, within the genes TLR4, GRM8, and SMAD3, respectively, were associated (p < 0.05) with MY305, rectal temperature (RT), and respiratory rate. Interestingly, these variables improved as the number of favorable genotypes of the SNPs increased from 0 to 3. In addition, a regression analysis detected RT as a significant predictor (R2 = 0.362) for MY305 in cows with >1 favorable genotype, suggesting this close relationship was influenced by genetic markers. In conclusion, SNPs in the genes TLR4, GRM8, and SMAD3 appear to be involved in the molecular mechanism that regulates milk production in cows under heat-stressed conditions. These SNPs are proposed as thermotolerance genetic markers for a selection program to improve the milk performance of lactating Holstein cows managed in a semiarid environment.

Genomic Prediction Accuracies for Growth and Carcass Traits in a Brangus Heifer Population.

The predictive abilities and accuracies of genomic best linear unbiased prediction (GBLUP) and the Bayesian (BayesA, BayesB, BayesC and Lasso) genomic selection (GS) methods for economically important growth (birth, weaning, and yearling weights) and carcass (depth of rib fat, apercent intramuscular fat and longissimus muscle area) traits were characterized by estimating the linkage disequilibrium (LD) structure in Brangus heifers using single nucleotide polymorphisms (SNP) markers. Sharp declines in LD were observed as distance among SNP markers increased. The application of the GBLUP and the Bayesian methods to obtain the GEBV for growth and carcass traits within k-means and random clusters showed that k-means and random clustering had quite similar heritability estimates, but the Bayesian methods resulted in the lower estimates of heritability between 0.06 and 0.21 for growth and carcass traits compared with those between 0.21 and 0.35 from the GBLUP methodologies. Although the prediction ability of the GBLUP and the Bayesian methods were quite similar for growth and carcass traits, the Bayesian methods overestimated the accuracies of GEBV because of the lower estimates of heritability of growth and carcass traits. However, GBLUP resulted in accuracy of GEBV for growth and carcass traits that parallels previous reports.

Silicon, by promoting a homeostatic balance of C:N:P and nutrient use efficiency, attenuates K deficiency, favoring sustainable bean cultivation.

BACKGROUND: In many regions of the world, K is being depleted from soils due to agricultural intensification a lack of accessibility, and the high cost of K. Thus, there is an urgent need for a sustainable strategy for crops in this environment. Si is an option for mitigating stress due to nutritional deficiency. However, the underlying effects of Si in mitigating K deficiency C:N:P homeostasis still remains unknown for bean plants. This is a species of great worldwide importance. Thus, this study aims to evaluate whether i) K deficiency modifies the homeostatic balance of C, N and P, and, if so, ii) Si supply can reduce damage caused to nutritional stoichiometry, nutrient use efficiency, and production of dry mass in bean plants. RESULTS: K deficiency caused a reduction in the stoichiometric ratios C:N, C:P, and P:Si in shoots and C:N, C:P, C:Si, N:Si, and P:Si in roots, resulting in a decrease in K content and use efficiency and reducing biomass production. The application of Si in K-deficient plants modified the ratios C:N, C:Si, N:P, N:Si, and P:Si in shoots and C:N, C:P, C:Si, N:Si, N:P, and P:Si in roots, increasing the K content and efficiency, reducing the loss of biomass. In bean plants with K sufficiency, Si also changed the stoichiometric ratios C:N, C:P, C:Si, N:P, N:Si, and P:Si in shoots and C:N, C:Si, N:Si, and P:Si in roots, increasing K content only in roots and the use efficiency of C and P in shoots and C, N, and P in roots, increasing the biomass production only in roots. CONCLUSION: K deficiency causes damage to the C:N:P homeostatic balance, reducing the efficiency of nutrient use and biomass production. However, Si is a viable alternative to attenuate these nutritional damages, favoring bean growth. The future perspective is that the use of Si in agriculture in underdeveloped economies with restrictions on the use of K will constitute a sustainable strategy to increase food security.

New approaches to the effects of Si on sugarcane ratoon under irrigation in Quartzipsamments, Eutrophic Red Oxisol, and Dystrophic Red Oxisol.

BACKGROUND: C:N:P homeostasis in plants guarantees optimal levels of these nutrients in plant metabolism. H However, one of the causes to the effects of deficit irrigation is the loss of C:N:P homeostasis in leaves and stems that causes reduction in the growth of sugarcane. Being able to measure the impact of water deficit on C:N:P homeostasis in plants from the stoichiometric ratios of the concentrations of these nutrients in leaves and stems. This loss causes a decrease in nutritional efficiency, but can be mitigated with the use of silicon. Silicon favors the homeostasis of these nutrients and crop productivity. The magnitude of this benefit depends on the absorption of Si by the plant and Si availability in the soil, which varies with the type of soil used. Thus, this study aims to evaluate whether the application of Si via fertigation is efficient in increasing the absorption of Si and whether it is capable of modifying the homeostatic balance of C:N:P of the plant, causing an increase in nutritional efficiency and consequently in the production of biomass in leaves and stems of sugarcane ratoon cultivated with deficient and adequate irrigations in different tropical soils. RESULTS: Water deficit caused biological losses in concentrations and accumulation of C, N, and P, and reduced the nutrient use efficiency and biomass production of sugarcane plants cultivated in three tropical soils due to disturbances in the stoichiometric homeostasis of C:N:P. The application of Si increased the concentration and accumulation of Si, C, N, and P and their use efficiency and reduced the biological damage caused by water deficit due to the modification of homeostatic balance of C:N:P by ensuring sustainability of the production of sugarcane biomass in tropical soils. However, the intensity of attenuation of such deleterious effects stood out in plants cultivated in Eutrophic Red Oxisols. Si contributed biologically by improving the performance of sugarcane ratoon with an adequate irrigation due to the optimization of stoichiometric ratios of C:N:P; increased the accumulation and the use efficiency of C, N, and P, and promoted production gains in biomass of sugarcane in three tropical soils. CONCLUSION: Our study shows that fertigation with Si can mitigate the deleterious effects of deficient irrigation or potentiate the beneficial effects using an adequate irrigation system due to the induction of a new stoichiometric homeostasis of C:N:P, which in turn improves the nutritional efficiency of sugarcane cultivated in tropical soils.

Frontal waves and transmissions for temporal laminates and imperfect chiral interfaces.

The analysis of wave patterns in a structure which possesses periodicity in the spatial and temporal dimensions is presented. The topic of imperfect chiral interfaces is also considered. Although causality is fundamental for physical processes, natural wave phenomena can be observed when a wave is split at a temporal interface. A wave split at a spatial interface is a more common occurrence; however, when the coefficients of the governing equations are time-dependent, the temporal interface becomes important. Here, the associated frontal waves are studied, and regimes are analysed where the growth of the solution in time is found. Imperfect interfaces, across which the displacements are discontinuous, are also considered in the vector case of chiral elastic systems. Analytical study and asymptotic approximations are supplied with illustrative numerical examples. This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 1)'.

Mineral supplementation (injectable) improved reproductive performance in Holstein cows managed in a warm summer environment.

Sustainability of dairy production depends largely on reproductive efficiency that is affected by heat stress due to high ambient temperature and humidity during summer. Supplementation of minerals has been proposed as a management strategy to minimize adverse impact of heat stress on fertility. The objective of this study was to determine the effects of an injectable mineral supplement (Fosfosan) containing selenium (Se), copper (Cu), potassium (K), magnesium (Mg) and phosphorus (P) on the ovarian structures, reproductive hormones and conception rate of heat-stressed Holstein cows. Sixteen cows were assigned during summer to one of two treatments, a control group (CON; n = 8) and a mineral-supplemented group (SUP; n = 8). Ambient temperature and relative humidity records were collected and processed to estimate the temperature-humidity index (THI), which confirmed a heat-stressed environment during the study (avg. THI = 79.4). Cows were subjected to a fixed-time artificial insemination (FTAI) program using the CIDR-Synch synchronization protocol. Traits indicative of ovarian activity were recorded during and after this protocol, as well as serum concentrations of reproductive hormones. Pregnancy diagnosis was made 28 and 35 d after FTAI. A completely randomized block design with repeated measures over time was performed to study ovarian functional structures and its hormonal profiles. Correlations and regressions were estimated to study relationships between ovarian structures and related hormones. Mineral supplementation did not increase follicular diameter or follicular populations (p > .05), yet tended to increase corpus luteum diameter (p < .10), and it enhanced (p < .01) oestrogen and progesterone serum concentrations and improved (p < .05) cow's conception rate. Diameter of dominant follicles and corpus luteum was correlated (p < .05) with oestrogen and progesterone levels, respectively, but only in mineral-treated cows. Two additional dairy herds were evaluated to confirm that mineral supplementation improved conception rate during the heat stress period (objective 2). Cows from dairy 1 received FTAI during winter (n = 401) and summer (n = 240), whereas cows from dairy 2 were bred after natural detected oestrus during winter (n = 558) and summer (n = 314). Conception rates were higher (p < .05) in winter than summer and they improved (p < .05) with mineral supplementation, but only in cows managed during summer. In conclusion, supplementation of minerals enhanced hormonal secretion from ovarian structures and improved conception rate in Holstein cows exposed to summer heat stress.

Diverse injury responses of human oligodendrocyte to mediators implicated in multiple sclerosis.

Early multiple sclerosis lesions feature relative preservation of oligodendrocyte cell bodies with dying back retraction of their myelinating processes. Cell loss occurs with disease progression. Putative injury mediators include metabolic stress (low glucose/nutrient), pro-inflammatory mediators (interferon γ and tumour necrosis factor α), and excitotoxins (glutamate). Our objective was to compare the impact of these disease relevant mediators on the injury responses of human mature oligodendrocytes. In the current study, we determined the effects of these mediators on process extension and survival of human brain derived mature oligodendrocytes in vitro and used bulk RNA sequencing to identify distinct effector mechanisms that underlie the responses. All mediators induced significant process retraction of the oligodendrocytes in dissociated cell culture. Only metabolic stress (low glucose/nutrient) conditions resulted in delayed (4-6 days) non-apoptotic cell death. Metabolic effects were associated with induction of the integrated stress response, which can be protective or contribute to cell injury dependent on its level and duration of activation. Addition of Sephin1, an agonist of the integrated stress response induced process retraction under control conditions and further enhanced retraction under metabolic stress conditions. The antagonist ISRIB restored process outgrowth under stress conditions, and if added to already stressed cells, reduced delayed cell death and prolonged the period in which recovery could occur. Inflammatory cytokine functional effects were associated with activation of multiple signalling pathways (including Jak/Stat-1) that regulate process outgrowth, without integrated stress response induction. Glutamate application produced limited transcriptional changes suggesting a contribution of effects directly on cell processes. Our comparative studies indicate the need to consider both the specific injury mediators and the distinct cellular mechanisms of responses to them by human oligodendrocytes to identify effective neuroprotective therapies for multiple sclerosis.

Effect of calving season on the parameters and components of the lactation curve in Holstein dairy cows managed in a semi-desert climate.

The lactation curve in dairy cows is influenced by the calving season, which is highly dependent on the warm climate in semi-arid regions. Objective herein was to evaluate effects of calving season on the parameters and components of the lactation curve in Holstein cows. The study included 278,317 milk records collected from 1086 cows from the 1st to 5th calving and good body condition score. The cows were grouped according to the season in which they calved: winter-calved (CS1), summer-calved (CS2), and autumn-calved cows (CS3). Ambient temperature and humidity data were used to calculate the temperature-humidity index (THI). The NLIN procedure was used to estimate the parameters of the lactation curve that served to calculate the components. The mixed procedure was executed to analyze the fixed effect of calving season. Associations between lactation curve traits were tested using correlation and regression analyses. A univariate model was utilized to calculate heritability. Average THI values during the lactation period were 73.5, 68.5, and 69.5 units for CS1, CS2, and CS3 groups, respectively. Initial milk production and increasing rate to the maximum milk yield in CS1 and CS3 groups were higher (P < 0.05) than CS2 cows. However, persistency and total milk yield during the entire lactation period were superior (P < 0.05) for CS2 and CS3 cows compared to CS1 cows, probably due to the moderate heat stress during the lactation period in the CS1 group. In cows from CS2 and CS3 groups, total milk production at 305 days was moderately correlated with initial milk production (r = 0.47; P < 0.05), and highly correlated with milk yield at peak day (r = 0.91; P < 0.05) which resulted as reliable predictor for total milk yield during the entire lactation (R2 = 0.83). In conclusion, the THI prevailing during the different calving seasons appeared to be an important factor influencing the performance of the lactation curve.

Pulmonary arterial pressure in fattened Angus steers at moderate altitude influences early postmortem mitochondria functionality and meat color during retail display.

Pulmonary hypertension is a noninfectious disease of cattle at altitudes > 1524 m (5,000 ft). Mean pulmonary arterial pressures (PAP) are used as an indicator for pulmonary hypertension in cattle. High PAP cattle (≥50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared to low PAP cattle (< 50 mmHg). The impact of pulmonary arterial pressure on mitochondrial function, oxidative phosphorylation (OXPHOS) protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg; n = 5) and low (41 ± 3 mmHg; n = 6) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 and 48 h) and retail display (days 1 to 9), respectively. High PAP muscle had greater (P = 0.013) OXPHOS-linked respiration and proton leak-associated respiration than low PAP muscles at 2 h postmortem but rapidly declined to be similar (P = 0.145) to low PAP muscle by 48 h postmortem. OXPHOS protein expression was higher (P = 0.045) in low PAP than high PAP muscle. During retail display, redness, chroma, hue, ratio of reflectance at 630 and 580 nm, and metmyoglobin reducing activity decreased faster (P < 0.05) in high PAP steaks than low PAP. Lipid oxidation significantly increased (P < 0.05) in high PAP steaks but not (P > 0.05) in low PAP. The results indicated that high PAP caused a lower OXPHOS efficiency and greater fuel oxidation rates under conditions of low ATP demand in premortem beef LL muscle; this could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function (membrane integrity or/and protein function) declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem by ROS damage in high PAP muscle.

The impact of pulmonary arterial pressure (PAP) on mitochondrial function, oxidative phosphorylation protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg) and low (41 ± 3 mmHg) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 and 48 h) and retail display (days 1 to 9), respectively. The results indicated that high PAP caused a lower oxidative phosphorylation efficiency and greater fuel oxidation rates under conditions of positive energy balance in beef LL muscle. This could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem in high PAP muscle.

A SNP within the PMCH gene as a molecular marker associated with fertility traits in Angus and Brangus beef heifers raised under a desert environment.

Components of the GH/IGF1 endocrine axis regulate growth and reproductive traits in cattle. The pro-melanin-concentrating hormone (PMCH) gene located within chromosome 5 belongs to this axis. Objective herein was to evaluate PMCH single-nucleotide polymorphisms (SNPs) as molecular markers associated with age at first calving, calving interval, and age at second calving in Angus and Brangus beef heifers raised in desert conditions. Five SNPs within the PMCH gene were included in the study. Three of these SNPs had minor allele frequency > 10% and only one SNP did not deviate from Hardy-Weinberg equilibrium. A genotype to phenotype association analyses was performed using a mixed-effects model which included phenotype as the response variable, SNP genotype, breed, year of birth and age of dam as fixed terms, and sire as a random effect. Genotypes from the SNP rs135033882 were found to be associated (P < 0.05) with all evaluated fertility traits, and the term breed resulted as a significant source of variation only for age at second calving. The allele A was the favorable allele because it decreased the age at first calving 98.6 days, the calving interval 85.3 days, and the age at second calving 183.1 days, in Angus and Brangus heifers. In conclusion, we proposed a SNP within the PMCH gene as a potential candidate marker associated with reproductive performance in Angus and Brangus beef heifers raised in a desert climate.