Adrenal responsiveness to a low-dose ACTH challenge in early and late lactating dairy cows.

To improve the evaluation of the chronic stress conditions, the adrenal responsiveness to low dose ACTH stimulation, in different lactation stages, was checked in 56 multiparous dairy cows from 2 herds (25-350 days in milk). Cows were retrospectively ranked in 3 stages: early (150 DIM) lactation. Herd B (vs. herd A) showed higher basal cortisol and frequency of inflammation. Early stage (vs. others) showed higher basal cortisol, bilirubin, ceruloplasmin and haptoglobin, as well as lower ones of cholesterol and lower rise of plasma cortisol during ACTH challenge (P<0.001). Cortisol peak was also correlated negatively with ceruloplasmin, bilirubin, ROM, and positively with cholesterol, vitamin A and E. Both, basal cortisol and cortisol response to ACTH, are associated to inflammation but in opposite way: basal cortisol positively and cortisol response negatively. This latter results are likely due to lower transcortin synthesis, that could be ensued in early lactating cows suffering inflammation

Variations of some blood parameters in rabbit reared under different environmental conditions

High environmental temperature induces physiological stress in rabbits leading to production losses, also because of their quite poor thermoregulation ability. Some consequences of heat stress affect digestive system functions, with impaired appetite, growth and feed conversion, but also with increased disease incidence. These effects can also reflect on the levels of some blood metabolites. Relatively few experimental works are available on the effects of high environmental temperature on the rabbit metabolic profile reared in commercial farms. The aim of this study was to study, in separate experiments, the effects of "fresh" spring and of "hot" summer temperatures on rabbits performance with particular attention to the behaviour of some metabolic parameters and of some aspects of the functionality of the digestive system

Inflammatory status and metabolic changes at dry-off in high-yield dairy cows

Our study investigates metabolic changes occurring at dry-off and the contribution of milk yield (MY) in such alterations. Thirteen Holsteins were dried off at 55 days from expected calving day (assumed as 0 days from dry-off, DFD) and divided in two groups according to their average daily MY in the last week of lactation, assuming a cut-off of 15 kg·d−1: low MY (7 cows) and high MY (6 cows). From −7 to 34 DFD dry matter intake (DMI) and rumination time were measured. Blood samples were collected at −7, 2, 7, 27 and 34 DFD to assess an haematological and metabolic profile and at −7, 7 and 34 DFD to test functions of circulating white blood cell (WBC) through ex vivo challenges. Data were included in a mixed model for repeated measures assuming MY at dry-off, time and their interaction as fixed effects. After dry-off, DMI was reduced and rumination time was increased in all the animals. High MY cows had greater DMI and rumination time than low MY cows. In blood, WBC counts decreased at 7 DFD and increased the production of pro-inflammatory cytokines at 7 and 34 DFD. Plasmatic concentrations of liver enzymes indicators, positive acute phase proteins (APPs); and nitrogen species increased after dry-off. Conversely, negative APPs and antioxidant species decreased. Those alterations were more marked in high MY animals. This study suggests that dry-off decreased liver function, triggered a systemic inflammation and depleted antioxidant systems, especially in the group of cows with high MY at dry-off.HighlightsInflammation, liver dysfunctions and altered redox balance has been detected after dry-off in all the animals.Cows with highest milk yield before halting of milk removal faced the most severe metabolic challenges.Such founding indicates the management of dry-off as a key point for dairy cows health. Inflammation, liver dysfunctions and altered redox balance has been detected after dry-off in all the animals. Cows with highest milk yield before halting of milk removal faced the most severe metabolic challenges. Such founding indicates the management of dry-off as a key point for dairy cows health

Pro-Inflammatory Cytokine Profile in Dairy Cows: Consequences for New Lactation

To verify the potential relevance of proinflammatory cytokine (PIC) with periparturient health problems and performances, the changes of plasma interleukin-1beta (IL-1β) and interleukin-6 (IL-6) have been investigated in 21 Holstein-Friesian cows from 35 d before to 28 d after parturition. The overall PIC concentration was higher during late pregnancy compared to the first month of lactation, but showed a high variability among the cows. Therefore, cows were retrospectively divided in 3 groups according to the values of area under the concentration curve of IL- 1β concentrations from -35 d before to the day of parturition and designated as up (UPIL1), intermediate (INIL1) and low (LOIL1) IL-1β group. The concentrations of IL-6 and to some extent the concentrations of albumin and reactive oxygen metabolites (ROMs) were well related to the grouping based on IL-1β concentrations. After calving the UPIL1 cows showed a more severe acute phase reaction (APR), based on the marked increase of haptoglobin and the lower plasma albumin concentrations during the first week of lactation, and the highest oxidative stress, based on the higher concentrations of ROMs. Moreover, the UPIL1 group showed higher number of mastitis, lower feed intake and milk yield compared with INIL1 and LOIL1. Our results demonstrated that cows with the highest PIC concentrations in the last month of pregnancy showed the worse health status in early lactation (clinical and subclinical problems) and a lower milk yield. Thus, these data support the utility of PIC measurement in late pregnancy as prognostic markers for a risky transition period

The effect of parity number on the metabolism, inflammation, and oxidative status of dairy sheep during the transition period.

The objective of this study was to evaluate whether dairy sheep during the transition period are affected by their parity numbers with regard to (1) body weight (BW), body condition score (BCS), and production performance (milk yield and composition) and (2) metabolic, inflammation, and stress biomarkers. For this purpose, 30 Sarda dairy ewes [15 primiparous (PRP) and 15 multiparous (MUP) ewes] were recruited on d 90 of gestation. Each group was homogeneous according to age, BW, and BCS. Sampling was carried out at -60, -30, -7, 0, +30, and +60 d from lambing. The MUP ewes showed a higher BW (46.32 vs. 38.71 kg) and larger litter size (1.45 vs. 1.06 kg) but a lower BCS (2.47 vs. 2.70) than the PRP ewes. Furthermore, the MUP ewes had lower concentrations of glucose (3.49 vs. 4.27 mol/L), cholesterol (1.63 vs. 1.81 mmol/L), free fatty acids (0.47 vs. 0.62 mmol/L), and triglycerides (0.22 vs. 0.25 mmol/L) compared with PRP ewes. With regard to inflammation and oxidative stress parameters, the PRP group had higher haptoglobin (0.48 vs. 0.18 g/L) and paraoxonase (187.90 vs. 152.11 U/L) activity than the MUP group. Overall, the MUP ewes were characterized by greater milk production performance and greater feed intake, resulting in a better energy balance, than the PRP ewes. Interestingly, these findings highlighted a different metabolic and inflammatory response over the transition period between PRP and MUP ewes, with the latter displaying lower concentrations of inflammatory-related biomarkers

Application of a NIR device for precision feeding in dairy farms: effect on metabolic conditions and milk production

Forages dry matter (DM) could vary among batches and in particular when silages are fed. These variations could modify nutrients composition of total mixed ration and affect cows performance. The aim of this study was to evaluate the effect of application of a precision feeding system (PFS) based on a near infra-red scanner, on metabolic conditions and milk yield in lactating dairy cows. The study was performed in 7 farms where PFS was installed on feed mixer to perform a weight-adjustment of DM measured in real time on feeds. A cross-over (14 weeks periods) was applied, PFS was switched on (PF-ON) in three herds and off in the other four (PF-OFF) during 1st period, and vice versa in 2nd period. At the end of two periods, in each herd 7 early and 7 mid lactation cows, for a total of 196 cows, were checked for: blood parameters, milk yield and composition. During the study deviation of DM of target diet (calculated on amount of feed in recipe and applying the DM determined in laboratory) and diets really distributed to cows tended to be lower with PF-ON vs. PF-OFF (0.06 vs 0.12 kg, p = .12). In early lactating cows, lower blood urea (4.63 vs 4.88 mmol/L, p = .115) indicated a better feed protein utilisation in PF-ON vs. PF-OFF. Milk yield and composition were not affected. The use of PFS meliorated the consistency of TMR, which could determine a better efficiency of nutrients utilisation and a reduction of production costs.Highlights Near infra-red (NIR) technology can be advantageously applied at farm level within a precision feeding system for dairy cows. The system allowed a more constant daily supply of nutrients with a reduction of metabolic alterations and a higher efficiency of feed protein utilisation. Utilization of NIR technology at farm level can be economically sustainable

Administration of an Immune Stimulant during the Transition Period Improved Lipid Metabolism and Rumination without Affecting Inflammatory Status

Omnigen-AF (OAF) increases leukocyte functions in immunosuppressed animal models and reduces incidence of infectious diseases in early lactating dairy cows, although its mode of action is still unclear. This study aims to provide a wider perspective of the metabolic eect of OAF to test its potential as a strategy to address metabolic disorders of the transition period. A group of 10 Holstein dairy cows were divided into 2 groups: The treated group (IMS; 5 cows) received 32.5 g of OAF twice a day (65 g d1) as top-dress in the morning and afternoon feeds from 55 to 42 days from calving (DFC), whereas the control group (CTR; 5 cows) received no supplementation. From 62 to 42 DFC, body condition score, body weight, dry matter intake, rumination time and milk yield were measured; blood samples were collected weekly to assess a wide hematochemical profile and to test white blood cell functions by ex-vivo challenge assays. At 30 DFC, rumen fluid was collected and analyzed for pH, volatile fatty acids composition, urea nitrogen, and lactate contents. Data were submitted to ANOVA using a mixed model for repeated measures, including treatment, time, and their interaction as fixed eects. OAF decreased blood nonesterified fatty acids and beta hydroxybutyrate concentrations and increased rumination time in early lactation. Leukocytes from IMS cows had lower lactate production and lower glucose consumption after ex-vivo stimulation. OAF did not reduce the acute phase response indicators and reduced the blood concentrations of albumin and antioxidants after calving, suggesting impairment of hepatic functions related to protein synthesis and antioxidant management. Nevertheless, the lack of eect on bilirubin and liver enzymes refutes the possibility of severe liver damage occurring with OAF supplementation. Positive eects in reducing mobilization of body fats and ketogenesis and in increasing rumination time after calving suggest OAF eectiveness in preventing metabolic disorders of the transition period

Genetic and environmental influences on in vitro digestibility of alfalfa

To study the relationships between in vitro NDF or true dry matter digestibility (NDFD and IVTDMD) and forage fibre content, 95 alfalfa samples from 5 cultivars grown in 3 different locations and from different cuts were analysed for fibre fractions and evaluated for NDFD and IVTDMD. NDFD was mainly influenced by order of cut and age of the fields. The multifoliate cultivar controlled did not appear to differ for fibre composition and NDFD from the other ones. Fibre fractions contents explained a large part of the difference in NDFD and IVTDMD, and no significant differences in this relationships appeared for first-cut vs. aftermath forage. The best predictive equation of NDFD from fibre factions was: NDFD = 73.61 -0.62 * NDF (% DM) – 56.33 * ADL/NDF (R2=0.39). Variations in fibre content and quality do not completely explain differences in NDFD suggesting the interference of other factors that are worth to be better studied

In vitro digestibility of field pea as influenced by processing methods

Field pea meals exposed to different treatments (flaking, extrusion, expansion, dry heating at 150°C/15' or 30', dry heating at 150°C/30' after addition of 1% of xylose, 4% NaOH addition, microwave irradiation at 800 W for 6' or 9') were controlled for their 6 and 24 hours in vitro fermentability by the gas production (GP) technique. Flaking and extrusion accelerated initial fermentation but tended to reduce 24h GP, whereas dry heating and microwaves mainly improved final gas volume, but NaOH had the opposite effect. Apparent dry matter digestion at 6h was lowered by dry heating, NaOH addition and the shorter microwave irradiation. Xylose addition did not substantially change the effects of dry heating, but lowered the initial disappearance. Ammonia concentration was in general lowered by the treatments, suggesting a reduction in protein degradability but also a possible higher microbial uptake for protein synthesis. Microwave irradiation had limited effects on all the parameters. Dry heating, with or without xylose addition, seems interesting to increase rumen escaping protein fraction without accelerating starch fermentation that could expose to higher risks of rumen acidosis

Effects of Hybrid and Maturity Stage on in Vitro Rumen Digestibility of Immature Corn Grain

This study aimed to evaluate the influences of hybrids (HYB) and maturity stage (SAMP) on in vitro rumen digestibility of immature corn grain. Four HYB (Gigantic, Y43, Klips and 9575) from the FAO group 700 were grown under identical agronomic conditions. First sampling (T1) was done after 95 days from seedling and then 4, 8, 13, 18 and 27 days later (T2 to T6). In vitro starch digestibility (STD_7h) and gas production (72 h) were measured. Whole plant and grain dry matter (WP_DM and GR_DM, respectively) and zein content were significantly affected (P<0.01) by HYB and SAMP. Starch content was significantly affected by HYB, SAMP and their interaction. It increased from T1 to T4 (from 67.47 to 72.82% of GR_DM) and then tended to plateau. Concurrently, STD_7h significantly decreased with advancing SAMP and was also affected by HYB. With advancing maturity, total volatile fatty acids (VFA) significantly decreased, with an increase of acetate and a decrease of propionate molar proportion (P<0.01). Gas production rate (GP_c) was significantly affected by HYB, SAMP and HYB×SAMP. Whole plant grain DM correlated (P<0.01) positively with grain starch content (r=0.60 and 0.64) but negatively with STD_7h (r=-0.39 and r=-0.63) and VFA concentration (r=-0.59 and -0.75). Zein percentage in crude protein negatively affected (P<0.01) total DM (r=-0.65,), STD_7h (r=-0.73) and GP_c (r=- 0.68). Results suggest that genotypes and maturity stages influence DM and rumen starch digestibility of immature corn grain and in this respect zein can play a significant role