Periods Of Negative Energy Balance Research Articles

Effects of treatment with propylene glycol and cyanocobalamin on disease, milk production and reproductive outcomes of dairy cows diagnosed with hyperketonemia and hypoglycemia

Almost all periparturient dairy cows experience a period of negative energy balance, and despite improvements to fresh cow management, some dairy cows still experience clinical dis­ease associated with the periparturient period (Duffield et al., 2009; Taylor et al., 2004). Hyperketonemia (HK) remains an im­portant production and animal welfare concern (McArt et al., 2012; Tatone, Duffield, Capel, et al., 2016; Tatone, Duffield, LeB­lanc, et al., 2016), and recently several handheld meters which measure beta-hydroxybutyric acid (BHBA) have been validated in dairy cows and can be used to detect pre-clinical HK (Bach et al., 2016; Tatone et al., 2015). Several studies have explored the screening of post-parturient cows to detect HK and adminis­ter treatment in order to ward off clinical disease and increase milk production (Capel et al., 2021; Gordon et al., 2017; McArt et al., 2012). However, these studies have been inconsistent in their findings, and treatment may not be economically beneficial for farms with a relatively low incidence of HK (McArt et al., 2014). A 2017 study indicated that cows may have variable production responses to HK treatment based on blood glucose concentra­tion (Gordon et al., 2017). Because blood glucose can also be mea­sured cow-side, measurement of blood glucose concurrent with measurement of blood BHBA may be a means to target treatment to cows that will respond to current treatments. Therefore, our objective was to explore the effects of treatment with propylene glycol and cyanocobalamin in early post-partum cows based on both HK and glycemic status. We hypothesized that improve­ments to health, milk production, and reproduction would be greatest among cows that were hypoglycemic.

Role of diacylglycerol O-acyltransferase 1 (DGAT1) in lipolysis and autophagy of adipose tissue from ketotic dairy cows

High-yielding dairy cows in early lactation often encounter difficulties in meeting the energy requirements essential for maintaining milk production. This is primarily attributed to insufficient dry matter intake, which consequently leads to sustained lipolysis of adipose tissue. Fatty acids released by lipolysis can disrupt metabolic homeostasis. Autophagy, an adaptive response to intracellular environmental changes, is considered a crucial mechanism for regulating lipid metabolism and maintaining a proper cellular energy status. Despite its close relationship with aberrant lipid metabolism and cyto-lipotoxicity in animal models of metabolic disorders, the precise function of diacylglycerol o-acyltransferase 1 (DGAT1) in bovine adipose tissue during periods of negative energy balance (NEB) is not fully understood. Particularly regarding its involvement in lipolysis and autophagy. The objective of the present study was to assess the impact of DGAT1 on both lipolysis and autophagy in bovine adipose tissue and isolated adipocytes. Adipose tissue and blood samples were collected from cows diagnosed as clinically ketotic (n = 15) or healthy (n = 15) following a veterinary evaluation based on clinical symptoms and serum concentrations of BHB, which were 3.19 mM (interquartile range = 0.20) and 0.50 mM (interquartile range = 0.06), respectively. Protein abundance of DGAT1 and phosphorylation levels of unc-51-like kinase 1 (ULK1), were greater in adipose tissue from cows with ketosis, whereas phosphorylation levels of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR) were lower. Furthermore, when adipocytes isolated from the harvested adipose tissue of 15 healthy cows were transfected with DGAT1 overexpression adenovirus or DGAT1 small interfering RNA followed by exposure to epinephrine (EPI), it led to greater ratios and protein abundance of phosphorylated hormone-sensitive triglyceride lipase (LIPE) to total LIPE and adipose triglyceride lipase (ATGL), while inhibiting the protein phosphorylation levels of ULK1, PI3K, AKT and mTOR. Overexpression of DGAT1 in EPI-treated adipocytes reduced lipolysis and autophagy, whereas silencing DGAT1 further exacerbated EPI-induced lipolysis and autophagy. Taken together, these findings indicate that upregulation of DGAT1 may function as an adaptive response to suppress adipocytes lipolysis, highlighting the significance of maintaining metabolic homeostasis in dairy cows during periods of NEB.

Circadian gene transcription plays a role in cellular metabolism in hibernating brown bears, Ursus arctos.

Hibernation is a highly seasonal physiological adaptation that allows brown bears (Ursus arctos) to survive extended periods of low food availability. Similarly, daily or circadian rhythms conserve energy by coordinating body processes to optimally match the environmental light/dark cycle. Brown bears express circadian rhythms in vivo and their cells do in vitro throughout the year, suggesting that these rhythms may play important roles during periods of negative energy balance. Here, we use time-series analysis of RNA sequencing data and timed measurements of ATP production in adipose-derived fibroblasts from active and hibernation seasons under two temperature conditions to confirm that rhythmicity was present. Culture temperature matching that of hibernation body temperature (34°C) resulted in a delay of daily peak ATP production in comparison with active season body temperatures (37°C). The timing of peaks of mitochondrial gene transcription was altered as were the amplitudes of transcripts coding for enzymes of the electron transport chain. Additionally, we observed changes in mean expression and timing of key metabolic genes such as SIRT1 and AMPK which are linked to the circadian system and energy balance. The amplitudes of several circadian gene transcripts were also reduced. These results reveal a link between energy conservation and a functioning circadian system in hibernation.

Dairy Cows Transition Period Feeding and Management

Proper feeding during the pregnancy and post-pregnancy period, determines the milk Production, ensuing lactation and as well as, the reproductive efficiency of the animal. 3 weeks before and 3 weeks after parturition are very important because a dramatic physiological and metabolic adaptation occurs during this period which is called the transition period. The Nutritional imbalances are caused by the low quality of desired nutritious rations, reduced appetite, and low ingestion which are responsible for depressed performance, specifically during the transition period. The absence of knowledge and skills of farmers in feeding management during the transition period exacerbates the situation. The metabolic changes, metabolic adaptations, Mechanism of a Transition period, transition period feeding management to prevent disorder, Decreased dry matter intake (DMI), Nutrient requirements, Infectious diseases and metabolic disorders, Nutritional management to Ease out the Transition Period, Management of the transition period, Feed additives supplementation and nutritional-management strategies to passage transition period are discussed by this review paper. Simultaneously, with the growth of the fetus, the nutrient requirements increase and are at their peak before parturition as well as immediately after parturition. The peak milk production reaches about 5–8 weeks postpartum, while the diet consumption peaks at 10–14 weeks postpartum. So, dairy cows will typically suffer a 6–8-week period of negative energy balance during the postpartum period. The requirement energy of the mammary at 4 days postpartum is more than three times than that of the uterus, with a simultaneous increase in the requirement of metabolizable protein, especially of methionine and lysine. The high metabolic incidence of infectious diseases is responsible for the high incidence of inflammatory conditions, mostly immediately after calving. To prevent mentioned diseases, pro-inflammatory cytokine release should be avoided postpartum. The body reserves mobilization, especially fat and protein; and hepatic gluconeogenesis takes place immediately after parturition leading to increased levels of β-hydroxy butyric acid and non-esterified fatty acids, which act as a gateway for several metabolic diseases. The phase of transition may eased by increasing DMI, feed conversion efficiency, density of ration, and protein supplements rich in rumen un-degradable protein; by using anionic mineral mixture, optimizing roughage to concentrate (R: C) ratio, optimum physically effective fiber length of forages/silage/hay, dietary buffers, feed additives such as inflammation modulators, protected nutrients, glucogenic precursors and direct-fed microbial/probiotics.

Exercise and Weight Management: The Role of Leptin—A Systematic Review and Update of Clinical Data from 2000–2022

A well-balanced metabolism means a lower risk for metabolism-related neuropsychiatric disorders. Leptin is a secretory adipokine involved in the central control of appetite that appears to play a role in the etiology of feeding-related disorders. Additionally, the influence of exercise on feeding behaviors potentially modulates the circulation of metabolites that signal through the central nervous system. In this systematic review, we collected the recent clinical evidence on the effect of exercise on leptin concentrations in health individuals published from 2000 to 20 September 2022, according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA 2020 statement). Six hundred and thirty-eight papers were retrieved and forty-eight papers were included in the qualitative synthesis. Data supports that exercise positively influences appetite via enhancing peripheral and central leptin signaling (reuptake), especially during weight loss. Exercise modulation of leptin signaling through leptin receptors helps to stabilize increases in food intake during periods of negative energy balance, prior to a decrease in the body fat tissue content. At a high intensity, exercise appears to counteract leptin resistance.

Haemato-biochemical Profiling in Buffaloes in Relation to Metabolic Changes during Transition Period

Background: Transition period is a critical period in which most dairy animals undergo a period of negative energy balance (NEB), hypocalcemia, insulin resistance, hypoglycemia and susceptibility to infectious diseases. The critical changes in biochemical indicators are well reported in dairy cows whereas; in dairy buffaloes limited data related to alterations in hemato-biochemical changes have been reported so far. The current study aimed to evaluate the hemato-biochemical changes in buffaloes during transition period. Methods: A total number of 210 buffaloes aged between 3 to 14 years with parity ranged from 1st to 4th, divided in three groups (n=70; each) during transition period were used for the study. Three groups viz Group I (-30 days), Group II (0 days) and Group III (+30 days) were subjected for evaluation of hemato-biochemical parameters. Result: Our study showed significant increase (p less than 0.05) in WBC (103/µl), lymphocytes and granulocytes count at the time of calving. Significant decrease (p less than 0.05) in the level of RBC, Hb and HCT were seen in Group-I and II. In biochemical analysis, parameters like albumin, total protein, triglyceride and A:G ratio showed significant (p less than 0.05) decrease from Group-I to II. Calcium and Ca:P ratio decreased significantly (p less than 0.05) along with suppressed levels of sodium and potassium levels in Group-III. Thus, the present study showed significance of hemato-biochemical analysis during transition period for possibility of occurrence of production diseases.

Pre-habilitation with exercise and high whey-protein-based meal replacement therapy promotes weight loss and preserve muscle mass before bariatric surgery

BackgroundBariatric surgery is considered as an effective therapy for those with morbid obesity. Preoperative weight loss with a very low-calorie diet is commonly used to ease the bariatric surgery. Pre-habilitation increases functional and physiological capacity. The study demonstrated the changes of body composition and functional status following short term pre-habilitation before bariatric surgery. MethodThis prospective study targeted those admitted for bariatric surgery. Participants underwent the biweekly pre-habilitation program included an individualized high whey-based protein very low-calorie (VLCHP) enteral regime (600–900 kcal/day) and moderate intensive exercise before bariatric surgery. Body composition and waist circumference were assessed after fortnight. Participants were segregated into morbid obese (MOG) (BMI <49 kg/m2) and super morbid obese group (SMOG) (BMI ≥50 kg/m2) for analysis. ResultMajority of participants were female (71%) with median age 36.0 years old (MOG) and 34.3 years old (SMOG) respectively. SMOG achieved significant greater loss in weight (−7.4 kg vs −4.0 kg), fat percentage (−4.4% vs −1.7%) and fat mass (−9.9 kg vs −3.8 kg); but MOG had a significant increment in muscle mass (3.2 kg vs 2.8 kg) as compared to SOG (p < 0.001). DiscussionBody composition measurement and changes remain critical in nutritional assessment to achieve successful surgery and minimize nutritional complication. Whey-based VLCHP attenuates muscle loss and preserves myofibrillar protein synthesis; promotes a better muscle strength and mass growth during periods of negative energy balance combined with moderately intense aerobic activity. ConclusionIndividualized whey-based VLCHP enteral regime and moderate intensive exercise encourage weight loss; increases muscle mass and strength; improve function status prior to bariatric surgery.

Irisin modulates glucose metabolism and inhibits steroidogenesis in bovine granulosa cells.

Fertility in the dairy cow is low during the post-partum period of negative energy balance and high plasma irisin concentrations. This study shows irisin modulates granulosa cell glucose metabolism and impairs steroidogenesis. Fibronectin type III domain-containing 5 (FNDC5) is a transmembrane protein discovered in 2012 that is cleaved to release the adipokine-myokine, irisin. Originally described as an exercise hormone that browns white adipose tissue and increases glucose metabolism, irisin secretion also increases during periods of rapid adipose mobilization, such as the post-partum period in dairy cattle when ovarian activity is suppressed. The effect of irisin on follicle function is unclear and may be species-dependent. In this study, we hypothesized that irisin may compromise granulosa cell function in cattle using a well-established in vitro cell culture model. We detected FNDC5 mRNA and both FNDC5 and cleaved irisin proteins in follicle tissue and in follicular fluid. The abundance of FNDC5 mRNA was increased by the treatment of cells with the adipokine visfatin but not by other adipokines tested. The addition of recombinant irisin to granulosa cells decreased basal and insulin-like growth factor 1- and follicle-stimulating hormone-dependent estradiol and progesterone secretion and increased cell proliferation but had no effect on viability. Irisin decreased GLUT1, GLUT3, and GLUT4 mRNA levels in granulosa cells and increased lactate release in the culture medium. The mechanism of action is in part through MAPK3/1 but not Akt, MAPK14, or PRKAA. We conclude that irisin may regulate bovine folliculogenesis by modulating granulosa cell steroidogenesis and glucose metabolism.

Does adaptive thermogenesis occur after weight loss in adults? A systematic review.

Adaptive thermogenesis (AT) has been proposed to be a compensatory response that may resist weight loss (WL) and promote weight regain. This systematic review examined the existence of AT in adults after a period of negative energy balance (EB) with or without a weight stabilisation phase. Studies published until 15 May 2020 were identified from PubMed, Cochrane Library, EMBASE, MEDLINE, SCOPUS and Web of Science. Inclusion criteria included statistically significant WL, observational with follow-up or experimental studies, age > 18y, sample size ≥10 participants, intervention period ≥ 1week, published in English, objective measures of total daily energy expenditure (EE) (TDEE), resting EE (REE) and sleeping EE(SEE). The systematic review was registered at PROSPERO (2020 CRD42020165348). A total of thirty-three studies comprising 2528 participants were included. AT was observed in twenty-seven studies. Twenty-three studies showed significant values for AT for REE (82·8 %), four for TDEE (80·0 %) and two for SEE (100 %). A large heterogeneity in the methods used to quantify AT and between subjects and among studies regarding the magnitude of WL and/or of AT was reported. Well-designed studies reported lower or non-significant values for AT. These findings suggest that although WL may lead to AT in some of the EE components, these values may be small or non-statistically significant when higher-quality methodological designs are used. Furthermore, AT seems to be attenuated, or non-existent, after periods of weight stabilisation/neutral EB. More high-quality studies are warranted not only to disclose the existence of AT but also to understand its clinical implications on weight management outcomes.

Bovine pyruvate carboxylase gene proximal promoter activity is regulated by saturated and unsaturated fatty acids in Madin-Darby bovine kidney cells

An increase in bovine pyruvate carboxylase (PC; EC 6.4.1.1) at calving and during feed restriction corresponds with increased circulating nonesterified fatty acids as a consequence of negative energy balance. Regulation of PC mRNA and effect of specific combinations of saturated and unsaturated fatty acid profiles has yet to be explored. Our objective was to determine the effects of chain length, degree of saturation, and copresence of saturated and unsaturated fatty acids on activity of bovine PC promoter 1 (PCP1). For these experiments, Madin-Darby bovine kidney cells were transfected with a full-length bovine PCP1 construct from -1002 to +3 bp relative to the bovine PC gene transcription start site (bovine PCP1(-1002_+3)) ligated to a Firefly luciferase reporter, or with one of a series of nested 5' serial truncations (bovine PCP1(-773_+3), bovine PCP1(-494_+3), or bovine PCP1(-222_+3)). Cells were exposed for 23 h to either individual fatty acids (C16:0, C18:0, or C18:3n-3 cis) bound to BSA or to fatty acid mixtures in ratios of 90:10, 75:25, 50:50, or 25:75, corresponding to combinations of C16:0: C18:3n-3 cis or C18:0: C18:3n-3 cis. Total fatty acid concentration was 1.00 mM. Exposure to either C16:0 or C18:3n-3 cis alone elicited a significant increase in capacity to drive bovine PCP1(-1002_+3) activity compared with 1% BSA in Dulbecco's Modified Eagle's Medium control treatment (2.29, 2.89, and 1.00 ± 0.26 fold of promoter induction for C16:0, C18:3n-3 cis, and control, respectively). Treatment with C18:3n-3 cis alone caused a greater increase in promoter activity compared with C16:0 alone, indicating a lesser response to C16:0 alone for bovine PCP1(-1002_+3). Interestingly, inclusion of C18:3n-3 cis, at any level of fatty acid ratios examined, in combination with C16:0 increased promoter activity of bovine PCP1(-773_+3) or bovine PCP1(-222_+3) compared with treatment with C16:0 alone or control. Data from the bovine PCP1 truncation and fatty acid copresence experiments reveal the potential for response elements of unsaturated fatty acids or fatty acid ligands in several bovine PCP1 promoter regions. In silico analysis of bovine PCP1 identified putative peroxisome proliferator-activated receptor α and sterol regulatory element binding protein binding sites which may be implicated in fatty acid signaling to alter bovine PCP1 activity. Pyruvate carboxylase promoter 1 activity that is mediated by unsaturated fatty acids acting through elements within -1002 and -222 bp of bovine PCPI may determine PC response during periods of negative energy balance in dairy cows.

Life cycle bioenergetics of the gray seal (Halichoerus grypus) in the Baltic Sea: Population response to environmental stress

Wildlife population dynamics are shaped by multiple natural and anthropogenic factors, including predation, competition, stressful life history events, and external environmental stressors such as diseases and pollution. Marine mammals such as gray seals rely on extensive blubber layers for insulation and energy storage, making this tissue critical for survival and reproduction. This lipid rich blubber layer also accumulates hazardous fat soluble pollutants, such as polychlorinated biphenyls (PCBs), that can directly impact adipose function or be mobilized during periods of negative energy balance or transferred to offspring to exert further impacts on target tissues or vulnerable life stages. To predict how marine mammals will respond to ecological and anthropogenic stressors, it is necessary to use process-based modelling approaches that integrate environmental inputs, full species life history, and stressor impacts with individual dynamics of energy intake, storage, and utilization. The purpose of this study was to develop a full lifecycle dynamic energy budget and individual based model (DEB-IBM) that captured Baltic gray seal physiology and life history, and showcase potential applications of the model to predict population responses to select stressors known to threaten gray seals and other marine mammals around the world. We explore variations of three ecologically important stressors using phenomenological simulations: food limitation, endocrine disrupting chemicals that reduce fertility, and infectious disease. Using our calibrated DEB-IBM for Baltic gray seals, we found that continuous incremental food limitation can be more detrimental to population size than short random events of starvation, and further, that the effect of endocrine disruptors on population growth and structure is delayed due to bioaccumulation, and that communicable diseases significantly decrease population growth even when spillover events are relatively less frequent. One important finding is the delayed effect on population growth rate from some stressors, several years after the exposure period, resulting from a decline in somatic growth, increased age at maturation and decreased fecundity. Such delayed responses are ignored in current models of population viability and can be important in the correct assessment of population extinction risks. The model presented here provides a test bed on which effects of new hazardous substances and different scenarios of future environmental change affecting food availability and/or seal energetic demands can be investigated. Thus, the framework provides a tool for better understanding how diverse environmental stressors affect marine mammal populations and can be used to guide scientifically based management.

Reference Gene Selection in Adipose and Muscle Tissues of Fat-tailed Lori-Bakhtiari Lambs

BACKGROUND: Fat-tailed sheep breeds have a unique ability to tolerate periods of negative energy balance due to seasonal changes in feed availability. This ability is attributed to presence of fat-tail as a body energy reserve, however the exact underlying mechanisms controlling the response of adipose tissue depots to variations in energy balance in fat-tailed breeds are not well understood. OBJECTIVES: As definition of a set of stable reference gene is an absolute prerequisite of any gene expression study, therefore the current research was conducted to define the most stable reference genes in adipose tissue depots and muscle of fat-tailed Lori-Bakhtiari lambs during periods of negative and positive energy balances. METHODS: Eighteen fat-tailed Lori-Bakhtiari male lambs were divided into 3 groups according to their body- weight. The experiment was consisted of an adaptation period (2 weeks), negative energy balance period (3 weeks), followed by positive energy balance period (3 weeks). The 3 groups of lambs were randomly selected and slaughtered at the beginning and end of negative energy balance and at the end of positive energy balance to collect samples of muscle and adipose tissue depots. RESULTS: The stability of the reference genes differed among different tissues and also between various depots of adipose tissue. Average of ranking by different software programs showed that glyceraldehyde 3-phosphate dehydrogenase (GAPDH), B-actin and peptidylprolyl isomerase A (PPIA) were the 3 most stable reference genes in mesenteric adipose tissue, whereas in fat-tail adipose tissue, PPIA, tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide (YWHAZ) and RNA polymerase II subunit A (POLR2A) were considered as genes with least expression variability during periods of negative and positive energy balance. B-actin, YWHAZ and phosphoglycerate kinase 1 (PGK1) were defined as the most stable reference genes in longissimus dorsi muscle tissue of Lori-Bakhtiari lambs. CONCLUSIONS: The results of the current study demonstrate that the stability of the reference genes varied between mesenteric and fat-tail adipose tissues and the level of energy balance affects the stability of the refer- ence genes. In addition, ranking of the reference genes differs among different software programs possibly due to different mathematical algorithms used by different programs.

A Tale of Two Biomarkers: Untargeted 1H NMR Metabolomic Fingerprinting of BHBA and NEFA in Early Lactation Dairy Cows.

Disorders of energy metabolism, which can result from a failure to adapt to the period of negative energy balance immediately after calving, have significant negative effects on the health, welfare and profitability of dairy cows. The most common biomarkers of energy balance in dairy cows are β-hydroxybutyrate (BHBA) and non-esterified fatty acids (NEFA). While elevated concentrations of these biomarkers are associated with similar negative health and production outcomes, the phenotypic and genetic correlations between them are weak. In this study, we used an untargeted 1H NMR metabolomics approach to investigate the serum metabolomic fingerprints of BHBA and NEFA. Serum samples were collected from 298 cows in early lactation (calibration dataset N = 248, validation N = 50). Metabolomic fingerprinting was done by regressing 1H NMR spectra against BHBA and NEFA concentrations (determined using colorimetric assays) using orthogonal partial least squares regression. Prediction accuracies were high for BHBA models, and moderately high for NEFA models (R2 of external validation of 0.88 and 0.75, respectively). We identified 16 metabolites that were significantly (variable importance of projection score > 1) correlated with the concentration of one or both biomarkers. These metabolites were primarily intermediates of energy, phospholipid, and/or methyl donor metabolism. Of the significant metabolites identified; (1) two (acetate and creatine) were positively correlated with BHBA but negatively correlated with NEFA, (2) nine had similar associations with both BHBA and NEFA, (3) two were correlated with only BHBA concentration, and (4) three were only correlated with NEFA concentration. Overall, our results suggest that BHBA and NEFA are indicative of similar metabolic states in clinically healthy animals, but that several significant metabolic differences exist that help to explain the weak correlations between them. We also identified several metabolites that may be useful intermediate phenotypes in genomic selection for improved metabolic health.

Effect of diet-induced negative energy balance on the feeding behavior of dairy cows

The objective of this study was to determine how feeding behavior of dairy cows is altered in response to diet-induced negative energy balance, and if this response varies depending on dietary particle size distribution. Multiparous Holstein cows (n = 30; days in milk = 59 ± 5; parity = 2.8 ± 0.19), producing 44.6 ± 1.2 kg/d of milk, were fed (on a dry matter basis) a lactating diet [net energy of lactation (NEL) = 1.66 Mcal/kg; 68% forage, including 1.8% wheat straw] during a 2-wk baseline period. To induce negative energy balance, cows were then exposed for 3 wk to 1 of 2 diets formulated for a 20% reduction in energy available for milk (NEL = 1.58 Mcal/kg; 73% forage, including 17.2% wheat straw). These diets were identical, only varying in straw chop length: (1) long straw diet (LS): straw chopped with a 10.2-cm screen, or (2) short straw diet (SS): straw chopped with a 2.54-cm screen. Cows consumed 25.6 ± 0.26 kg/d during the baseline period. Dry matter intake decreased on the experimental diets; dry matter intake was greater for the SS diet as compared with the LS diet (23.1 vs. 22.5 kg/d; standard error = 0.47). During the baseline period, cow serum nonesterified fatty acids (NEFA) and blood β-hydroxybutyrate averaged 0.27 ± 0.02 and 0.71 ± 0.05 mmol/L, respectively. During the experimental period, NEFA and β-hydroxybutyrate averaged 0.34 and 1.04 mmol/L, respectively, with a peak of NEFA (0.63 ± 0.06 mmol/L) occurring 4 d after dietary change. During baseline, cows produced 42.3 ± 0.33 kg/d of milk; milk yield was decreased for both SS cows and LS cows during the experimental period (SS = 39.0, LS = 37.8 kg/d; standard error = 0.67). On the experimental diets, cows spent more time eating (266.8 vs. 221.8 min/d), had longer meal lengths (46.9 vs. 37.5 min/meal), and consumed fewer meals (7.1 vs. 7.7 meals/d) compared with the baseline period. Within the experimental period, LS cows spent more time eating per day than SS cows (LS = 281.3, SS = 252.2 min/d). During the baseline period cows sorted against long particles (>19 mm), did not sort medium particles (8 to 19 mm), and sorted for short (4 to 8 mm) and fine (<4 mm) particles. Cows did not change sorting of long particles on the SS diet, but increased sorting against these on the LS diet. On the SS diet cows did not change their sorting of short and fine particles. On the LS diet cows increased sorting for short and fine particles. In the baseline period, no association was detected between feed sorting and serum NEFA concentration. During the experimental period, greater NEFA concentration was associated with greater sorting in favor of short particles for both the LS and SS diets. Furthermore, greater NEFA concentration was associated with greater sorting against the longest particles for both the LS and SS diets. No associations of blood and meal variables were detected during the experimental period. Overall, cows altered their feed sorting behavior in response to experiencing a diet-induced period of negative energy balance and the severity of negative energy balance was associated with the extent of that change in feed sorting.

The Risk Assessment of Oxidative Stress in Postpartum Dairy Cattle

Background: Negative energy balance in cows will induce catabolism especially of lipids and the resulting rapid increase of free fatty acids (NEFA) in the blood stream increases the production of reactive oxygen metabolites (ROMs) and promote oxidative stress. Once the animal body is in an oxidative stress state, many molecules in the body may be peroxidized, accelerating the destruction of cells and causing damage to tissues or organs. This study conducted risk assessment of the oxidative stress caused by negative postpartum energy balance in cows by exploring the relationship between negative energy balance and oxidative stress.Materials, Methods &amp; Results: This experiment randomly selected 120 cows at 14 to 21 days postpartum, from an intensive cattle farm in Heilongjiang province, China. Using a negative energy balance standard of β-hydroxybutyric acid (BHBA) greater than 1.2 mmol/L, nonesterified fatty acid (NEFA) greater than 0.4 mmol/L and glucose (GLU) less than three mmol/L, the cattle were divided into a healthy group of 74 cows and a diseased group of 46 cows. The oxidative stress indices of the experimental cows were measured and analyzed using the independent sample t test. Spearman correlation analysis and regression analysis were performed and by using the binary Logistic regression analysis to predict disease, the receiver-operating characteristic curve (ROC) analysis established diagnosis effect and boundary values. Compared with the healthy group, the levels of glutathione peroxidase (GSH-Px), catalase (CAT), vitamin E (VE), selenium (Se) and total nitric oxide synthetase (T-NOS) in the blood of dairy cows in the diseased group were significantly reduced and the level of malondialdehyde (MDA) was significantly increased. The study concluded that negative energy balance is associated with oxidative stress in cows and the blood levels of GSH-Px, CAT and Se can be used to evaluate the degree of resulting oxidative stress. The early warning levels were determined to be GSH-Px less than 619.28 U/L, CAT less than 7.87 U/ml and Se less than 0.51 μg/L.Discussion: The levels of GSH-Px, CAT, Se, T-NOS and VE in the blood of cows in the disease group were lower than those in the healthy control group. This may be due to the increase in energy demand of cows in the perinatal period and the decrease of DMI in this period, which promotes the NEB of cows. In order to alleviate the NEB, the body forces its metabolic enhancement. Some tissues of the body cannot adjust their metabolism to adapt to NEB and this leads to excessive NEFA, which causes oxidative stress. Excessive NEFA can also affect the expression of GSH-Px in cells, and causing a series of oxidation reactions, increased free radicals and as the antioxidant system is overwhelmed. The MDA content in the blood of the deficient group was significantly increased compared with the healthy group, positively correlated with NEFA and BHBA and negatively correlated with GLU. This may be due to severe oxidative stress in cows during the period of negative energy balance as MDA is one of the important products of membrane lipid peroxidation. Long chain PUFA are an important component of all cell membranes and their oxidation damages the integrity, fluidity and function of cell membranes. In summary MDA causes oxidative damage to cells, damages mitochondrial membranes and changes membrane permeability, resulting in more free radicals produced by mitochondria during biological oxidation.

Calcium Propionate Increased Milk Parameters in Holstein Cows

Background: In the early lactation, dairy cows go through a period of negative energy balance because they do not intake enough food to supply the energetic demand of milk production. In this period, dairy cows are susceptible to metabolic disorders, although has little evidence that milk production contribute to increase diseases occurrence. Some alternatives to minimize metabolic disorders, that reduce milk yield, has been suggested, as increase energy density in the diet of dry cows 21 days before the parturition and include additives in the diet pre and post-partum. The aim of this study was to measure the productive parameters in dairy cows fed calcium salts as energetic source. Materials, Methods &amp; Results: Two Latin square 4x4 were used, whereas one comprehended of early lactation cows and the other of mid lactation cows. Animals of 2nd and 3rd parity were used only. Parity was distributed evenly among groups. The trial consisted of 4 groups with 4 treatments as follow: T1: 300 g of calcium acetate, T2: 200 g of calcium propionate, T3: 200 g of calcium salts of fatty acids, and T4: control without any calcium additive. The animals were milked twice a day, the first milking at 07:00 am and the second milking at 05:00 pm. Milk samples were collected in plastic containers with potassium dichromate. These samples were sent to the Laboratory of Milk Analysis of the Paranaense Association of Breeders of the Holstein Breed for analysis of fat, protein, lactose and total solids through the infrared method. Throughout the experimental period, the daily production of the animals under study was recorded. The production of milk (kg) was corrected to 3.5% fat using the formula PLA 3.5% = (0.432 + kg milk) + (0.1623 x kg milk x fat content).Discussion: Greater supply of glucose or propionate stimulate milk protein production, but the mechanism of this stimulation is unclear. Milk protein is dependent on energy supply, and deficient energy intake reduces milk protein levels. Calcium propionate provided enough energy supply and increased milk protein levels. The synthesis of lactose has influence in water absorption in mammary gland and lactose determine milk osmolarity. The lactose levels vary according blood glucose, somatic cells count and energy availability for physiological processes. In the literature, rarely has been found greater lactose concentration caused by feed intake, becoming very important the results found in this work. The diet energy concentration and consumption rate determine energy intake, which limit milk yield. Dairy cows in early lactation has marked increased of nutrient requirements to support milk production. Support milk lactose synthesis in the mammary gland is the one of responsible for increase of nutrients requirements. In this period, the glucose demands increases 2 times more than during late gestation. Propionate is converted to glucose in the liver and it will be support lactose synthesis in the mammary gland. Propionate supplementation in this work provided better energetic supply and it is possible to consider, evaluating the milk yield. It was concluded that calcium propionate increased milk parameters like: milk protein, lactose and milk fat. Holstein cows fed calcium propionate had greater milk yield than other groups.

Testosterone Status Following Short-term, Severe Negative Energy Balance Predicts Fat-free Mass Loss in U.S. Marines

Male US military personnel exposed to periods of severe negative energy balance often experience marked reductions in circulating total testosterone, and it is not uncommon for concentrations to fall below normal levels (<300 ng/dL). However, testosterone fluctuations following severe negative energy balance are variable, and little is known about the metabolic and physiological differences between males who experience low testosterone (LT) and those who maintain normal testosterone (NT). PURPOSE: To determine metabolic and physiological differences between males with LT versus those with NT following 8 d of strenuous military training. METHODS: Male US Marines (n = 68) were dichotomized based on testosterone concentration (< or ≥ 300 ng/dL) following 8 d of severe negative energy balance incurred during military training. Body composition (DEXA) and whole-body protein turnover (15N alanine) were measured and blood and urine samples collected before (PRE) and after (POST) training. Linear mixed models were used to assess the effects of testosterone status, time, and their interaction on outcomes. RESULTS: Testosterone concentrations decreased PRE (505 ± 135 ng/dL) to POST (284 ± 115 ng/dL, P < 0.01). When volunteers were dichotomized by POST testosterone status (NT, n = 24: 407 ± 97 vs. LT, n = 44: 217 ± 52 ng/dL, P < 0.01), PRE BMI, total fat mass, and testosterone were greater in NT compared to LT (P < 0.05). LT lost more fat-free mass (FFM, -3.4 ± 1.3 kg) and less fat mass (-2.4 ± 1.2 kg) compared to NT (-2.4 ± 2.0 and -3.2 ± 1.6 kg, respectively; P-interaction < 0.03). Insulin (+5.55 ± 9.35 μU/mL) and norepinephrine (+0.23 ± 0.29 ng/mL) increased from PRE to POST in LT, whereas no changes occurred in NT (+1.03 ± 3.75 μU/mL and +0.04 ± 0.30 ng/mL, respectively), resulting in significant differences between groups (P-interaction < 0.02). Independent of time, LT had greater whole-body protein synthesis, breakdown, and flux (P-status < 0.01), but not net balance (P-status = 0.2), compared to NT. CONCLUSION: Military personnel susceptible to operational stress-induced LT may be predisposed to greater FFM loss during periods of negative energy balance incurred during short-term, strenuous military training. Supported by US Army Medical Research and Materiel Command; authors’ views not official US Army or DoD policy.

Glucose and insulin responses to an intravenous glucose tolerance test administered to feed-restricted dairy cows receiving folic acid and vitamin B12 supplements

The present experiment was conducted to determine whether, during periods of negative energy balance, the increase in glucose availability, despite similar DMI and greater milk production, induced by a combined supplement of folic acid and vitamin B12 was related to effects of insulin on metabolism. Sixteen multiparous Holstein cows averaging 45 days in milk (standard deviation: 3) were assigned to 8 blocks of 2 animals each according to their milk production (45 kg/d; standard deviation: 6) during the week preceding the beginning of the experiment. Within each block, they received weekly intramuscular injections of either saline (CON) or folic acid and vitamin B12 (VIT) during 5 consecutive weeks. During the last week, the cows were fed 75% of their ad libitum intake during 4 d. Blood samples were taken the morning before starting the feed restriction and on the third day of feed restriction. On the fourth day of feed restriction, the daily meal was not served and an intravenous glucose tolerance test was performed. During the 4 wk preceding the feed restriction, milk production and DMI were not affected by treatments. During the feed restriction, the vitamin supplement tended to decrease milk fat concentration and increase milk concentration of lactose. Plasma concentrations of homocysteine, Ile, Leu, Val, and branched-chain AA increased in VIT cows during the restriction but not in CON cows. During the glucose tolerance test, insulin peak height was lower and insulin incremental positive area under the curve tended to be lower for VIT than for CON [83 (95% confidence interval, CI: 64-108) vs. 123 (95% CI: 84-180) µg·180 min/L, respectively]. Free fatty acid nadir was reached earlier for VIT than for CON [34 (95% CI: 26-43) vs. 46 (95% CI: 31-57) min, respectively]. Glucose area under the curve, clearance rate and peak height, insulin time to reach the peak and clearance rate, and free fatty acid nadir did not differ between VIT and CON. The reduction in insulin release during a glucose tolerance test without changes in glucose clearance rate or area under the curve suggests that the vitamin supplement improved insulin sensitivity in feed-restricted lactating dairy cows.

Follicle growth, corpus luteum function and their effects on embryo development in postpartum dairy cows

Absent or irregular ovarian cycles in lactating dairy cows are caused by failure to ovulate the dominant follicle at the appropriate time. The follicle then either regresses or develops into a cyst. This process can be triggered by a variety of metabolic and disease factors that act at the hypothalamus and pituitary gland to inhibit pulsatile LH secretion and the LH surge, and at the ovary to reduce follicular growth and oestradiol production. Cows of poor energy status have low circulating concentrations of insulin-like growth factor I (IGF-I). Predisposing factors include calving difficulties, inappropriate diet, reduced intake of dry matter and a high rate of body condition score loss. Various stressors predispose the follicle to cyst development by inhibiting the LH surge and ovulation; these include common infections, such as mastitis. Even when ovulation does occur, poor follicular development may result in production of an inadequate corpus luteum. The timing of the increase in progesterone in the early luteal phase (days 4–5) appears to be a key determinant of fertility, probably because it alters the secretory activity of the reproductive tract, thus influencing embryonic growth and interferon-τ production. A period of negative energy balance after calving can reduce fertility even though metabolic parameters have apparently improved at the time of service.

Effect of non-perforating abomasal lesions on reproductive performance, milk yield and carcass weight at slaughter in Danish Holstein cows

Non-perforating abomasal lesions are common in Danish Holstein cows, but the impact on production has not been studied. Our objective was to compare milk yield, carcass weight, days to first service and initiation of breeding among cows with different non- perforating abomasal lesion types and locations to cows with no such lesions.The occurrence, type and localisation of non- perforating abomasal lesions were characterised at slaughter in Danish Holstein cows, and first insemination dates (n = 592), milk yield (n = 999) and carcass information (n = 1,317) was also available. Production and reproduction data were retrieved from all other cows from the herds of origin. This information was used to evaluate the expected production performance in the herds.Of the 1,317 cows investigated at slaughter, 572, 428, 677, and 91 cows had at least one lesion Subtype 1a (mucosal erosion), 1b (acute deeper lesion), 1c (chronic deeper lesion) or 1d (scarring following a lesion), respectively. Cows with lesion Subtype 1c and lesions in the pyloric part of the abomasum were generally found to be culled later in lactation than their herd mates. Milk yield and days to first service were not associated with any lesion types. The occurrence of lesion Subtype 1c and lesions in the pylorus were associated with a higher weight at slaughter compared to cows without lesions of this subtype or in this location. Most Subtype 1c lesions was found in the pylorus. Initiation of breeding before 150 days in milk was positively associated with the number of lesions in the corpus of the abomasum.We discovered two sources of selection bias. First, cows with lesions had a higher carcass weight but also remained in the herds for longer after calving than cows without lesions. This would give them more time to overcome the period of negative energy balance in early lactation. Second, although the causes of culling were not known, cows with no lesions generally had a relatively low milk yield and could have been culled for this reason.”. While non- perforating abomasal ulcers may have an effect on the production and reproduction data, the observational data presented show no evidence of such a relationship. It may be necessary to employ other study designs to identify any effects that might exist, but if the relationship cannot be demonstrated in a dataset of this magnitude, it is not deemed to be of practical relevance.