Lactation Performance Research Articles

155 Modulating silage fermentation with microbial inoculants

Abstract Silage is a vital feed ingredient for beef and dairy cattle diets in many areas worldwide. Even though ensiling is a well-established method of forage preservation, producers face a myriad of challenges to produce, harvest, and store forages optimally. Challenging circumstances like these create difficulties for proper silage fermentation, increase dry matter (DM) losses and silage contamination with mycotoxins, and reduce the nutritive value of ensiled forages. Losses of DM and nutrients occur during production, fermentation, and feeding of silage. Although some losses are unavoidable, poor management may increase DM losses up to 60% which may eventually lead to decreased feed efficiency, as each percentage-unit lost as DM is a percentage-unit of feed that cannot be converted into animal products. Loss of DM during forage production and preservation is estimated to cost beyond a billion dollars worldwide. Even in well-managed silages, yeasts and molds that survive anaerobic fermentation may grow rapidly and reduce aerobic stability after silo opening, and mold count in silage is positively related to DM loss. The use of silage microbial inoculants is a key strategy to modulate silage fermentation and preserve forage successfully. This presentation will discuss microbial inoculant strategies to optimize silage fermentation and minimize silage losses. Homofermentative bacterial inoculants, which contain bacteria that almost exclusively produce lactic acid, have been shown to effectively reduce silage pH and improve DM recovery. The use of homofermentative microbial inoculants have been shown to attenuate DM loss during ensiling and to increase dry matter intake and hence lactation performance by dairy cows. Heterofermentative bacterial inoculants, which contain bacteria capable of producing both lactic and acetic acids, reduce mold and yeast counts and improve silage aerobic stability.

Impact of heat stress during close-up dry period on performance, fertility and immunometabolic blood indices of dairy cows: prospective cohort study

This study aimed to investigate whether heat stress, as defined by the temperature-humidity index (THI) during the close-up dry period, had any impact on the productive performance, fertility, and immunometabolic blood indices of dairy cows in the subsequent lactation. Lactation performance was associated with increasing THI values on − 21, − 14, and − 7 d before calving resulting in decreased milk yield by about 2.30, 2.60, and 2.90 kg, respectively. The THI on the − 7 d before the calving was negatively associated with fertility parameters such as delayed first estrus postpartum, an elongated calving interval by approximately 32 d, a higher number of services per conception by 1.00, and an elongated artificial insemination service period, days open, and inter-calving period by about 20, 52, and 52 d, respectively. The study found that the immunometabolic blood indices were associated with increasing THI values during the close-up dry period. The study showed that exposing dairy cows to close-up dry period heat stress had negative consequences on performance, fertility, and immunometabolic blood indices in the subsequent lactation. Therefore, it is recommended that herd management and barn microclimate changes be implemented earlier, starting from the late dry period, to mitigate the negative impact of heat stress.

Feed additives supplementation: a potential strategy to ameliorate heat stress in sheep

Abstract Given a significant climate-flexible and socio-economic role in developing nations, environmental heat stress imposes a major financial impact on sheep production systems globally endangering their production, reproduction, and growth. In this regard, the adverse effects of heat stress on sheep production systems have to be addressed through adoption of effective heat alleviation measures like animal management, nutritional management and genetic interventions of which the nutritional interventions seems to be the most cost effective way to alleviate heat stress. Nutritional manipulation for heat stress alleviation in sheep involves the use of antioxidant supplements (Vitamin B; Vitamin E and Selenium; Selenium; Zinc sulphate and folic acid; Vitamin C, Vitamin E, Selenium and Zinc; Naringin; Opuntia ficus-indica f. inermis; Açai oil and Brown seaweed like Ascophyllum nodosum and Sargassum latifolium). Further, electrolyte supplements (Dietary Electrolyte Balance (DEB); Sodium bicarbonate and potassium bicarbonate; Sodium hydroxide) have a beneficial effect on thermal responses, respiratory activities, gas exchange parameters, rumen fermentation, blood buffering capacity and acid-base balance. The mineral mixture supplements (Mineral blocks; Mineral mixture and antioxidants; Chromium; Zinc) play a crucial role in increasing the efficiency of antioxidant defence system, immunity-related parameters, production, reproduction, feed digestibility and insulin sensitivity. Probiotic supplements (Lactobacillus acidophilus, Saccharomyces cervisiae, Propionibacterium freudenreichii, Lactobacillus casei, Enterococcus faecium, Lactobacillus lactis, Bacillus subtilis, Propionibacterium freudenreichii, Pediococcus cerevisiae, Megaspha eraelsdenii, Bacillus licheniformis, Aspergillus oryzae, Schizochytrium limacinum, Trichoderma reesei and Saccharomyces cerevisiae) improve lactational performance, dietary energy utilization and productivity. The probiotics (live Saccharomyces cerevisiae) and prebiotics (mannan oligosaccharide plus b-glucans) used in heat stress alleviation improve dietary energy utilisation. Furthermore, the vital role of herbal supplements (Rosemary, Cinnamon, Turmeric, Clove, Naringin, Chestnut tannins, Giloy stem powder, Curcumin, Rocket oil (watercress oil), Flaxseed, Cornus, Oregano, Thyme, Chamomile flowers, Moringa oleifera, Betaine) has been highlighted to promote feed intake, antioxidant status, growth performance, feed utilization, reproductive performance and immune response. Effective adoption of nutritional strategies can thus ensure sustainable sheep production in this changing climate scenario.

444 The effects of increasing standardized ileal digestible lysine-to-net energy ratio during at 24-day lactation period on primiparous sow nitrogen utilization and lactation performance

444 The effects of increasing standardized ileal digestible lysine-to-net energy ratio during at 24-day lactation period on primiparous sow nitrogen utilization and lactation performance

Accuracy and precision of diets fed to close-up cows on dairy farms and its association with early lactation performance

Ensuring a consistent ration is critical for maximizing lactating cow performance, but this is not known for dry cows. The objectives of this cohort observational study were to: 1) characterize close-up dry cow diets fed on commercial farms in Ontario, Canada, 2) describe the accuracy of the nutrient composition between the formulated close-up diet and the diet offered to the cows, 3) describe the precision of the close-up diets across time, and 4) explore potential associations of that accuracy and precision with blood metabolic parameters and milk yield of cows in early lactation. Forty free-stall dairy farms were visited once every 4 wk, for a total of 6 visits to each farm, from April to October 2022. At each visit, samples of the close-up diet were collected and analyzed for dry matter (DM) content and chemical composition. Close-up diet formulations were also obtained by each farm's nutritionists. During each visit, fresh cows (0 to 14 d in milk [DIM]) had blood samples taken for blood metabolites. The same cows were also monitored for milk yield up to 120 DIM. Multivariable models were used to analyze associations between variability (in relation to the formulated diet and across time) of nutrients in the close-up diet, as measured by coefficient of variation (CV), and outcomes in fresh cows. Corn silage (67.6% of farms) and straw (24.3% of farms) were the predominant primary forage sources used in the close-up dry cow diets. Soybean meal (37.8% of farms) and canola meal (18.9% of farms) were the main ingredients used as primary concentrate sources. Overall, the diets offered did not accurately represent the formulated diets. With the exception of net energy for lactation (NEL), the CVs for the other nutrients were all greater than 5%. Diet variability, both between fed and formulated diets and from visit to visit during the close-up period, was associated with metabolic markers and dairy cow production. Lower variability in non-fiber carbohydrates (NFC) between the fed and formulated diets was associated with better liver health index scores. Visit-to-visit variability in fat% and NFC% were associated with blood β-hydroxybutyrate (BHB) concentrations, while NFC% variability was associated with blood glucose levels. Serum nonesterified fatty acids (NEFA) concentrations were associated with visit-to-visit variability in DM% and CP%. These results underscore the importance of maintaining consistency between diet formulations and feeding practices over time to optimize early-lactation dairy herd performance and health, granted that these diets are correctly formulated to meet the nutritional needs of cows in the close-up period and applied with recommended feeding practices.

Impact of feed efficiency on young beef animals on adult resilience: From field challenge experiments to modelling approaches

The relationship between feed efficiency at young ages and resilience as cows has been examined using an experiment that combines residual feed intake (RFI) evaluation of beef heifers and subsequent dietary challenge as cows. Feed efficiency of 569 heifers of 22 months of age was estimated during a 70-day period. Then a dietary challenge was applied on 303 of these animals after their first calving, half of them being fed 30 % below their expected needs from 10 days after calving up to the start of the grazing period (around mid-April), after which all the animals received the same management. When possible, the animals were kept until third lactation, giving a total of 514 lactations. Dam weight, dam BCS and calf weight were measured regularly, dam milk production was estimated three times during the lactation and resumption of cyclicity was recorded as well. The experimental data were analyzed using linear models including the effects of heifer efficiency (RFI <-0.4 = efficient; RFI >0.4 = inefficient) and interaction of heifer efficiency and diet group. The data were also used to calibrate a herd dynamics model representing management-nutrition and reproduction interactions at animal level. The experiment data showed that the efficient heifers were 18 kg heavier as cows when fed ad libitum (P = 0.04) but no difference was observed when restricted. Within both diets, heifers classified as efficient produced between 6 and 12 % less milk as cows than inefficient heifers depending on the lactation stage (P < 0.01), with a subsequent effect on calf weight. Finally, the resumption of cyclicity was one week shorter for the efficient animals when fed ad libitum but the opposite was observed within the restricted group, representing a complete ovarian cycle difference between diet groups within the efficient class (P = 0.001). In the lifetime modelling approach, two clusters of animals with different characteristics, including RFI, were simulated under both a non-restricted and restricted feeding environment. In this simulation, efficient heifers produced lighter cows with lower intake and higher body reserves from second calving until culling. Non-efficient heifers had better productive (kg of weaned calf) performance as cows independently of environment. The simulated reproductive performance of cows was equal for animals coming from efficient and non-efficient heifers under the non-restricted environment whereas efficient heifers perform better in the restricted environment, especially when parity increases. Both approaches showed that the interplay between efficiency at young ages and short- and long-term resilience depends on the environment. It can be concluded that the selection for efficiency at young ages has a negative impact on lactational performance as cows but not necessarily on reproductive resilience.

Differences in Lactation Performance, Rumen Microbiome, and Metabolome between Montbéliarde × Holstein and Holstein Cows under Heat Stress.

Heat stress negatively affects lactation performance and rumen microbiota of dairy cows, with different breeds showing varying levels of heat tolerance. This study aimed to compare the lactation performance of Montbéliarde × Holstein (MH, n = 13) and Holstein (H, n = 13) cows under heat stress, and 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC-MS) were used to determine the rumen microbiome and metabolome in experimental cows. The results indicated that during heat stress, milk yield (p = 0.101), milk fat yield, milk protein yield, milk protein, and milk lactose (p < 0.05) in Montbéliarde × Holstein cows were higher than those in Holstein cows, whereas milk yield variation and somatic cell counts (p < 0.05) were lower than those in Holstein cows. The sequencing results indicated that the rumen of Montbéliarde × Holstein cows was significantly enriched with beneficial bacteria, such as Rikenellaceae, Allobaculum, and YRC22 (p < 0.05). In addition, correlations were observed between specific ruminal bacteria and lactation performance. Ruminal metabolites related to antioxidant and anti-inflammatory properties were significantly higher (p < 0.05) in Montbéliarde × Holstein cows than in Holstein cows. Overall, Montbéliarde × Holstein cows showed higher production efficiency under heat stress, which may be related to the different rumen mechanisms of crossbred and Holstein cows in adapting to heat stress.

Fermented total mixed ration enhances nutrient digestibility and modulates the milk components and fecal microbial community in lactating Holstein dairy cows.

Fermented total mixed ration (FTMR) is an effective method of preserving high-moisture byproducts with higher aerobic stability after fermentation. FTMR has the potential to fulfill the daily nutritional requirements of cattle and enhance their production performance. The objective of this research was to examine the influence of FTMR on lactation performance, total tract apparent digestibility, fecal microbiota communities, and fermentation profiles in lactating dairy cows. A total of 12 cows were randomly assigned into two groups: the TMR group and the FTMR group. The TMR group was fed a total mixed ration (TMR) diet, and the FTMR group was fed an FTMR diet. The FTMR did not impact milk yield in dairy cows despite a decrease in dry matter intake, which increased the efficiency of the feed. In contrast to that in the TMR group, the milk fat content in the FTMR group was greater. The FTMR group showed greater digestibility of neutral detergent fiber (NDF), organic matter (OM), dry matter (DM), crude protein (CP), and acid detergent fiber (ADF) in the total digestive tract than did the TMR group. The FTMR increased the concentration of butyrate in the fecal matter and reduced the pH of the feces. The Chao1, ACE, and Shannon indices of the archaeal community in dairy cow feces were significantly higher in cow fed the FTMR compared to those fed the TMR. LefSe analysis revealed higher levels of Oscillospira, Lactobacillus, Prevotella, and Dehalobacterium in the feces of dairy cows fed the FTMR than in those fed the TMR. However, the abundances of Roseburia, rc4-4, Bulleidia and Sharpea exhibited the opposite trend. The abundances of Halobacteria, Halobacteriales, and Halobacteriaceae, which are biomarkers for distinguishing fecal archaea in the TMR from the FTMR, were substantially greater in the feces of dairy cows that consumed the TMR than in those that consumed the FTMR. Therefore, FTMR can improve the milk fat content, total tract apparent feed digestibility efficiency, and diversity of archaea in the feces. Additionally, this work provides a theoretical basis for the feasibility of FTMR feeding for dairy cows.

Comparison of lipidome profiles in serum from lactating dairy cows supplemented with Acremonium terrestris culture based on UPLC-QTRAP-MS/MS

This study evaluated the effects of supplementing the diet of lactating cows with Acremonium terrestris culture (ATC) on milk production, serum antioxidant capacity, inflammatory indices, and serum lipid metabolomics. Over 90 days, 24 multiparous Chinese Holstein cows in mid-lactation (108 ± 10.4 days in milk, 637 ± 25 kg body weight, 30.23 ± 3.7 kg/d milk yield) were divided into either a control diet (CON) or a diet supplemented with 30 g of ATC daily. All the data were analyzed using Student’s t test with SPSS 20.0 software. The results showed that compared with CON feeding, ATC feeding significantly increased milk yield, antioxidant capacity, and immune function. Lipidome screening identified 143 lipid metabolites that differed between the two groups. Further analysis using “random forest” machine learning revealed three glycerophospholipid serum metabolites that could serve as lipid markers with a predictive accuracy of 91.67%. This study suggests that ATC can be a useful dietary supplement for improving lactational performance in dairy cows and provides valuable insights into developing nutritional strategies to maintain metabolic homeostasis in ruminants.

Effects of Acremonium terricola Culture on Lactation Performance, Immune Function, Antioxidant Capacity, and Intestinal Flora of Sows.

This study aimed to determine the effects of different doses of Acremonium terricola culture (ATC) on lactation performance, immune function, antioxidant capacity, and intestinal flora of sows. Forty-five Landrace sows (3-6 parity) were randomly assigned to the following three treatments from 85 days of gestation to 21 days after farrowing: a control diet (CON, basal diet), a low-dose Acremonium terricola culture diet (0.2% ATC, basal diet + 0.2% ATC), and a high-dose Acremonium terricola culture diet (0.4% ATC, basal diet + 0.4% ATC). Compared with the CON group, the supplementation of 0.2% ATC increased the average daily milk yield of sows by 4.98%, increased milk fat, total solids, and freezing point depression on day 1 postpartum (p < 0.05), increased serum concentration of Triiodothyronine, Thyroxin, and Estradiol on day 21 postpartum (p < 0.05). Compared with the CON group, the supplementation of 0.4% ATC increased the average daily milk yield of sows by 9.38% (p < 0.05). Furthermore, the supplementation of 0.2% ATC increased serum concentration of IgG, IgM, and IFN-γ, CD4 on day 1 postpartum (p < 0.05) and increased serum concentration of immunoglobulin A ( IgA), immunoglobulin G (IgG), immunoglobulin M ( IgM), complement 3 (C3), cluster of differentiation 4 (CD4), cluster of differentiation 8 (CD8), interferon-γ (IFN-γ) on day 21 postpartum (p < 0.05), while the supplementation of 0.4% ATC reduced serum concentration of IL-2 on day 21 postpartum (p < 0.05). Moreover, the supplementation of 0.4% ATC significantly increased serum concentration of catalase (CAT) (p < 0.05). Additionally, the supplementation of ATC affected the relative abundance of the intestinal flora at different taxonomic levels in sows and increased the abundance of beneficial bacteria such as in the norank_f__Eubacterium_coprostanoligenes group, Eubacterium_coprostanoligenes group, and Lachnospiraceae_XPB1014 group of sows, while reducing the abundance of harmful bacteria such as Phascolarctobacterium and Clostridium_sensu_stricto_1. These data revealed that the supplementation of ATC during late gestation and lactation can improve lactation performance, immune function, antioxidant capacity, and the gut microbiota. Compared with supplementation of 0.4% ATC, 0.2% ATC enhances the levels of thyroid-related hormones, specific antibodies, and cytokines in serum, promotes the diversity of beneficial gut microbiota, beneficial bacteria in the intestine, reduces the population of harmful bacteria, and thereby bolsters the immunity of sows. Hence, 0.2% ATC is deemed a more optimal concentration.

Rumen-protected methionine supplementation during the transition period under artificially induced heat stress: Effects on cow-calf performance

This study aimed to evaluate the effects of rumen-protected Met on lactation performance, inflammation and immune response, and liver glutathione of lactating dairy cows during a subclinical mastitis challenge (SMC). Thirty-two Holstein cows (145 ± 51 DIM) were enrolled in a randomized complete block design. At -21 d relative to the SMC, cows were assigned to dietary treatments, and data were collected before and during the SMC. Cows were blocked according to parity, DIM, and milk yield and received a basal diet (17.4% CP; Lys 7.01% MP and Met 2.14% MP) plus 100 g/d of ground corn (CON; n = 16) or a basal diet plus 100 g/d of ground corn and rumen-protected Met (SM, Smartamine M at 0.09% of dietary DM; n = 16), fed as a top-dress. At 0 d, the mammary gland's rear right quarter was infused with 100,000 cfu of Streptococcus uberis (O140J). Milk yield was recorded twice daily from 0 until 3 d relative to SMC. Milk samples were collected during each milking from 0 to 3 d relative to SMC, blood samples were collected at 0, 6, 12, 24, 48, and 72 h relative to SMC. The mTOR pathway activation was assessed in immune cells in blood and milk samples by measuring quantity and phosphorylation status of mTOR-related proteins, including AKT, S6RP, and 4EBP1. For the ratio of phosphorylated to total AKT, S6RP, and 4EBP1, blood samples were collected at 0, 12, and 24 h, and milk samples at 24 h relative to SMC. Liver biopsies were performed at -10 d and 24 h relative to SMC for measurement of glutathione. Linear mixed models with repeated measures were used to analyze the results. There was a trend for greater milk yield per milking (+ 0.8 kg) and per day (+1.7 kg) after SMC in SM cows compared with CON. The DMI was not affected by dietary treatments. Reactive oxygen metabolites (ROM) were lower in SM cows than in CON. Milk somatic cell linear score was not affected by dietary treatments, and a score >4 at 24 h confirmed subclinical mastitis. The SM cows had greater milk fat percentage at 24 and 36 h post SMC, resulting in overall greater milk fat. Milk protein tended to be greater in SM cows than in CON. We observed greater liver glutathione in SM cows than in CON. Among inflammation biomarkers, ceruloplasmin was lower for SM cows compared with CON. In milk, greater pAKT:AKT and pS6RP:S6RP ratios were observed in immune cell populations from SM cows compared with CON. Blood neutrophils had a greater p4EBP1:4EBP1 ratio in SM cows compared with CON. Overall, our results show that Met supplementation during an SMC positively affected milk performance, lowered the risk of oxidative stress, and attenuated inflammation partially by increasing liver glutathione and immune cells' protein synthesis via mTOR signaling.

Feeding gilts and sows to maximize mammary development and lactation performance

Increasing sow milk yield is essential to achieve maximal growth of suckling piglets, and nutrition can stimulate milking capacity. From 90 days of age until puberty, replacement gilts should not undergo major feed restriction as it will inhibit mammary development. Providing phytoestrogens in that period will stimulate mammary hyperplasia. During gestation, feed intake of gilts must ensure that backfat at the end of gestation is above 16 mm to support mammary development. In the last third of gestation, providing 40% more lysine than requirements via the addition of soybean meal increases mammary mass in gilts, but not in multiparous sows. A high nutrient intake during transition is crucial, whereby providing sows 12.6 Mcal metabolizable energy and 22.0 g standardized ileal digestible (SID) Lys daily ensures a high colostrum production and maximizes milk yield in the following lactation. During lactation, there are quadratic effects of energy and protein intakes on the weight of suckled mammary glands and sows should not be restricted-fed to avoid excessive mobilization of body reserves. Furthermore, the provision of adequate lysine is critical to maximize litter growth, with optimum daily intakes between 47.7 and 51.3 g SID Lys for primiparous sows and 51.3–67.2 g SID Lys for multiparous sows.

Assessing Transition Cow Management in Dairy Cows for Improved Health, Milk Production, Pregnancy and Culling Outcomes

Understanding of the social environment has the potential to benefit dairy cow welfare and production. Our aim was to evaluate the associations of stocking density, calving density, days spent in a pre-partum group before calving (days spent in close-up, DCU) and the number of days from a pen filling event (addition of new cows to the pre-partum pen) on early-lactation health, production, pregnancy and culling outcomes in dairy cows. Data were gathered from 2780 cows in 2 herds. Herd management and reproductive records were analyzed for cows receiving treatment in the first 30 d of lactation (days in milk, DIM) for clinical mastitis, reproductive tract disease, ketosis, milk fever and displaced abomasum. Principal component analysis was used to account for the relationship between gestation length (GL) and DCU and their association with early lactation disease, milk production, pregnancy and culling outcomes. The effect of stocking density, the number of days from a pen filling event to calving and the calving density experienced by a cow in her week of calving was also evaluated. Causal inference was used to correct for confounding bias due to farm identity. The odds of disease in the first 30 DIM increased with stocking density before calving. A quadratic association was found between the first principal component (PC1), representing the combined effect of GL and DCU, and the odds of disease in multiparous cows only. Early lactation milk production and 305 d milk production in multiparous cows increased with PC1 score. Quadratic relationships were found between stocking density at d 8 to 2 before calving with both early lactation and 305 d milk production in multiparous cows but no associations were found in primiparous cows. Calving density showed a quadratic association with 305 d milk production in primiparous cows. The number of days from the last pen filling event to calving was not associated with changes in milk production. Disease occurrence was negatively associated with both early lactation and 305 d milk yield in multiparous cows but only with early lactation milk production in primiparous cows. The occurrence of disease was associated with a delayed time to pregnancy only in primiparous cows while both disease and being in lactation group ≥ 3 were negatively associated with time to pregnancy in multiparous cows. Week 4 milk (W4MK) was positively associated with reduced time to pregnancy in multiparous cows. For primiparous cows, increasing age at calving was associated with increased culling risk, while being in lactation group ≥ 3 was associated with increased culling risk in multiparous cows. Culling risk decreased with increasing W4MK in all cows. These results suggest that gestation length, time spent in close-up and stocking density are important factors influencing disease incidence in early lactation and subsequent lactation performance but had differing effects on primiparous versus multiparous cows. A better understanding of how pre-partum management factors influence postpartum health and milk production can help farms to plan facilities and organize the day-to-day management of cows and will assist in improving cow welfare and productivity.

Dietary fiber source and direct-fed microbial supplementation effects on lactation performance and feeding behavior of high-producing dairy cows

The objective of this study was to evaluate the effects of dietary fiber source and direct-fed microbial supplementation on lactation performance and feeding behavior of high-producing dairy cows. Sixty-four multiparous Holstein cows (3.5 ± 1.6 lactations; 76 ± 22 DIM and 735 ± 67 kg of BW at covariate period initiation) and 32 gate feeders were enrolled in a study with a completely randomized design and a 2 × 2 factorial arrangement. Cows and gate feeders were randomly assigned to treatments (16 cows and 8 gate feeds per treatment). Cows were allowed 1 week to acclimate to feeding gates followed by a 2-week covariate period. During the acclimation and covariate periods, all cows were fed the same diet to meet or exceed the nutrient requirements. Following the covariate period, cows were enrolled in a 8-week treatment period during which cows were randomly assigned to 1 of 4 treatments consisting of forage inclusion in the diet, either 45.8% (LF) or 56.7% (HF) of DM, and the supplementation of 75 mL/hd/d of a direct-fed microbial (DFM) containing herbal extracts (mallow, mint, and sage), L. plantarum, L. buchneri, Saccharomyces cerevisiae, and sugar cane molasses (Valibiom Mix, Valibiotics, Traiskirchen, Austria) or without supplementation (CON). The average covariate period value of each variable was used as a covariate. Three-way interactions were observed for DMI and feed efficiency. Dry matter intake was 2 to 3 kg greater for LF-DFM than HF-CON and HF-DFM during wk 2, 3, 5, and 8 of the treatment period. Milk production was 2.1 kg/d greater for LF than HF diets. Both milk fat and MUN concentrations were greater for HF than LF diets. Conversely, milk protein concentration was lower for HF than LF diets. The respiration rate measured in the morning was lower with DFM supplementation than CON. Rectal temperature measured in the morning and averaged for the day were greater for LF than HF diets. Under the conditions of the present study, feeding high-forage diets may be an alternative for producers to reduce feeding costs depending on the price of purchased feeds. However, non-forage fiber sources (i.e., soy hulls) must be considered when producers are challenged by either forage shortages or forage with a lower nutritive value. Additionally, DFM supplementation reduced respiration rate in the morning and affected meal behavior of lactating cows.

Estimations of prepartum feed intake and its effects on transition metabolism and subsequent milk production

The objectives of this study were to identify factors associated with prepartum DMI, evaluate the performance of linear models to estimate prepartum DMI using different classes of predictors, and investigate the consequences of different levels of prepartum DMI on transition metabolism and lactation performance. Individual feed intake of nulliparous (n = 100) and parous cows (n = 173) was measured by automatic feeding bins from d -35 to 98 relative to calving. Rumination and physical activities were monitored by wearable sensors. Blood metabolites were measured on d -21, -10, -3, 0, 3, 7, 10, 14, and 21. Body weight (BW) and body condition score (BCS) were assessed throughout the study. The average prepartum DMI as percentage of BW (DMIpBW) was calculated for each cow and used as dependent variable of linear models. Parity, prepartum BCS and BW, milk production in the previous lactation (M305) and at dry-off (MYDO), and length of the dry period were associated with DMIpBW and explained 41% of the variation in all cows, and 49% in parous cows. Estimations of DMIpBW were improved when data on prepartum rumination and blood metabolites were added in the predictive models. In the latter, the adjusted R-Sq increased to values between 47 and 61%, and selected models performed consistently in a 5-fold cross-validation analysis. To evaluate the implications of DMIpBW to transition metabolism and performance, cows were ranked within parity and classified into terciles as low (LFI), moderate (MFI), or high feed intake (HFI). The mean DMI was 1.44, 1.70, and 1.91 ± 0.01% of BW, respectively. No differences in BW were observed in nulliparous cows, but all 3 groups of parous cows differed (LFI = 892, MFI = 849, HFI = 798 ± 8 kg). The proportion of cows with BCS > 3.5 at enrollment differed among all groups, and averaged 67.4, 55.1, and 36.5 ± 6%, respectively. For parous cows, M305 and MYDO differed among all groups and averaged 9,808, 10,457, and 11,182 ± 233 kg, and 18.1, 23.1, and 26.2 ± 1 kg/d, respectively. After calving, DMI (LFI = 20.9, MFI = 21.9, and HFI = 22.1 ± 0.2 kg/d) and milk yield (LFI = 36.7, MFI = 38.2, and HFI = 38.3 ± 0.4 kg/d) was lower in LFI cows compared with the other 2 groups. Postpartum EBAL differed among all groups and averaged -2.79, -1.63, and -0.66 ± 0.3 Mcal/d for LFI, MFI, and HFI, respectively. During the transition period, LFI cows had higher serum concentrations of NEFA, BHB, Cl (prepartum only), and AST (postpartum only), and lower serum concentrations of cholesterol, P, GLDH, GGT (prepartum only), AST (prepartum only), urea (parous only), and SOD activity (parous only). In conclusion, a low level of prepartum DMI was associated with fatter and heavier cows, lower milk production in previous lactation, important adjustments in energy metabolism, and moderate losses in DMI and milk yield in the subsequent lactation. Moreover, the inclusion of prepartum rumination activity and target blood metabolites into predictive models improved the estimations of prepartum DMI.

Effects of heat stress on endocrine, thermoregulatory, and lactation capacity in heat-tolerant and -sensitive dry cows.

Increasing global temperatures present a significant challenge to livestock production. The dry period is an important stage in the production cycle of cow, and environmental heat stress (HS) during this period can have adverse effects on the subsequent lactation performance. In this study, we aimed to investigate the effects of HS on endocrine, thermoregulatory, and lactation parameters in heat-tolerant dry cows (HTDC) and heat-sensitive dry cows (HSDC). We measured the respiratory rate (RR), body temperature (BT), and temperature-humidity index (THI) in 66 dry cows during HS. The slopes of RR and BT to THI were determined through analysis of measurements and dry cows background information using a mixed-effects model. Subsequently, the heat tolerance or sensitivity of dry cows was assessed using clustering method (HTDC = 19 and HSDC = 47). Compared with that of HSDC, the RR of HTDC significantly increased after exposure to HS (p < 0.05). The average reduction in milk yield from new lactation to the previous lactation was significantly lower in HTDC compared to HSDC (p < 0.05). Plasma cortisol and non-esterified fatty acid levels were significantly lower in HTDC compared to HSDC (p < 0.05), while plasma triiodothyronine (p = 0.07) and growth hormone (p = 0.08) levels tended to be higher in HTDC relative to HSDC. HTDC can more effectively alleviate the impacts of HS through their superior thermoregulation and metabolism, thereby ensuring optimal postpartum lactation performance.

Effects of biochanin A on lactational performance, nitrogen metabolism, and blood metabolites in dairy cows

Optimizing nitrogen utilization efficiency and mitigating nitrogen losses in cows plays a pivotal role in fostering economic sustainability within contemporary agricultural systems. Biochanin A (BCA), a natural component in red clover, has the potential to improve nitrogen metabolism in dairy cows. The primary objective of this study was to probe the impact of biochanin A supplementation on lactational performance, nitrogen metabolism, and blood metabolites in dairy cows. A complete randomized block design experiment was conducted over 28 d, involving 36 multiparous Holstein cows (comparable milk yield = 37.1 ± 2.90 kg, BW = 642 ± 70.0 kg, days in milk = 92 ± 8.0 d, and parity = 2.4 ± 0.50), which were allocated to three treatment groups: the Control group (with 0 g/d BCA), the Low group (with 10 g/d per cow BCA), and the High group (with 40 g/d per cow BCA). Biochanin A supplementation improved the lactational performance of cows by increasing milk yield by 6.3% (P = 0.007) and feed efficiency by 12.7% (P = 0.009). Total intestinal apparent digestibility was unaffected by BCA supplementation (P > 0.05), but microbial nitrogen was increased by 30.0% (P = 0.002) for promoting nitrogen utilization efficiency by 20.7% (P = 0.004). Milk competent yields (protein, lactose, and non-fat milk solid) were increased with increasing BCA supplementation (P < 0.05). Urea nitrogen levels in plasma and milk were both decreased by BCA supplementation (P < 0.05). Blood routine parameters and plasma biochemical parameters both received no effect by BCA supplementation (P > 0.05). BCA did not affect body health of dairy cows. Additionally, none of the plasma endocrine hormones were affected (P > 0.05). A total of 95 significantly different metabolites were screened from the plasma metabolites of cows in the BCA-added and non-added groups. After performing an enrichment analysis of the metabolic pathways associated with the different metabolites, six specific pathways were identified: bile acid biosynthesis, aspartate metabolism, pyrimidine metabolism, arginine and proline metabolism, the urea cycle, and ammonia recycling. The inclusion of BCA is suggested to enhance milk yield and modulate nitrogen metabolism by influencing relevant metabolites within the metabolic pathways.

A novel approach using copper oxide nanocomposites-based biosensor for lactate detection in athletes

Accurate monitoring tools are necessary for lactate, a critical biomarker linked to anaerobic metabolism and muscular performance. Lactate dehydrogenase (LDH) immobilized on MXene (Ti3C2Tx)-supported CuO nanocomposites (MCNs) modified glassy carbon electrode (LDH/MCN/GCE) is the innovative electrochemical biosensor for lactate detection presented in this work. CuO nanostructure integration onto MXene nanosheets, MCN production, and LDH immobilization were all successfully accomplished, according to structural characterization performed using XRD, SEM, XPS, and FTIR. The best lactate oxidation current was shown by LDH/MCN/GCE, according to electrochemical study. With a low detection limit of 0.25 µM and a high sensitivity of 5.92107 µA/mM, the biosensor exhibited a linear response range of 0.1–121 mM. The remarkable selectivity, stability, and sensitivity were attributed to enhanced LDH immobilization made possible by MCNs and MXene. The promise of LDH/MCN/GCE for bioanalytical applications is highlighted by promising results from practical testing in human blood samples, opening the door for improvements in lactate monitoring and performance optimization techniques.

Cystatin SN (CST1) Is a Poor Independent Prognostic Biomarker for Gastrointestinal Diffuse Large B-Cell Lymphoma.

BACKGROUND Gastrointestinal diffuse large B-cell lymphoma (GI-DLBCL) is the most common histological subtype of extra-nodal DLBCL, but the risk factors, prognostic biomarkers, histopathological classifications, and treatment strategies have not had significant progress. Emerging evidence shows that cystatin SN (CST1) is involved in tumor progression in several cancer types, but its role in GI-DLBCL has not been revealed. MATERIAL AND METHODS We established a cohort consisting of 84 patients with GI-DLBCL who underwent surgical resection. The expression of CST1 in the cohort was investigated by immunohistochemistry, which divided the patients into subgroups with low or high expression of CST1. Moreover, the CST1 expression in GI-DLBCL tissues or adjacent GI tissues were compared with RT-qPCR. The correlation between CST1 expression and clinicopathological factors was analyzed with the chi-square test. The prognostic significance of CST1 was estimated by univariate and multivariate analysis, and statistical significance was analyzed with the log-rank test. RESULTS CST1 was aberrantly upregulated in GI-DLBCL tissues compared with in non-tumor GI tissues. High expression of CST1 indicated poor prognosis of GI-DLBCL (P=0.012), and CST1 can be regarded as an independent prognostic biomarker of GI-DLBCL (hazard ratio=3.07). In our study, serum lactate dehydrogenase (P=0.002), performance status (P=0.003), Lugano stage (P=0.002), and International Prognostic Index (P=0.001) were also prognostic factors of GI-DLBCL. CONCLUSIONS CST1 is an independent prognostic biomarker of GI-DLBCL, indicating unfavorable prognosis. Our results suggested that CST1 detection can be a promising method to stratify high-risk patients and guide individual treatment.

Development and application of a 1K functional liquid chip for lactation performance in Bactrian camels.

The advancement of high-throughput, high-quality, flexible, and cost-effective genotyping platforms is crucial for the progress of dairy breeding in Bactrian camels. This study focuses on developing and evaluating a 1K functional liquid single nucleotide polymorphism (SNP) array specifically designed for milk performance in Bactrian camels. We utilized RNA sequencing data from 125 lactating camels to identify and select 1,002 loci associated with milk production traits for inclusion in the SNP array. The array's performance was then assessed using 24 randomly selected camels. Additionally, the array was employed to genotype 398 individuals, which allowed for population validation to assess the polymorphism of SNP sites. The SNP array demonstrated high overall SNP call rates (> 99%) and a remarkable 100% consistency in genotyping. Population validation results indicate that camels from six breeding areas in Northwest China share a similar genetic background regarding lactation functionality. This study highlights the potential of the SNP array to accelerate the breeding process of lactating Bactrian camels and provides a robust technical foundation for improving lactation performance.