Birthe Marie Damgaard

Ontogeny and characterization of blood leukocyte subsets and serum proteins in piglets before and after weaning

Existing knowledge about the development of the porcine immune system was extended by phenotypic characterization of leukocyte subsets and with assessment of Mannan-Binding Lectin (MBL) and immunoglobulin concentrations in peripheral blood of healthy piglets. Single-color and/or double-color flow cytometry using monoclonal antibodies against CD1, CD3, CD4, CD8a CD14, CD21, CD172 (SWC3a), CD284 (TLR4), SLA I, and SLA II were performed to identify T-lymphocyte subsets, B-lymphocytes, monocytes, and granulocytes. ELISA was used to measure the concentration of serum proteins. Several of the analyzed parameters seem to be affected at the time of weaning which took place at 4-5 weeks of age. Using principal component analysis, all analyzed variables - except one - were grouped into 8 factors with distinct developmental profiles. Several of these factors revealed an apparent suppression, a steady state or an acceleration of the developmental age profiles around weaning. In conclusion, results indicate that weaning suppresses a broad spectrum of adaptive immune variables and that this was evident immediately after weaning as well as after a lag period of about one week. On the contrary, variables of the innate immune system seem to be stimulated immediately after weaning. At the time considered to have the highest infection pressure T-cells and TLR4+ cells were markedly enhanced, whereas the expression of SLA I did not seem to be affected by weaning.

Effects of thermal environment on hypothalamic-pituitary-adrenal axis hormones, oxytocin, and behavioral activity in periparturient sows.

Provision of additional floor heating (33 to 34 degrees C) at birth and during the early postnatal hours is favorable for newborn piglets of domestic sows (Sus scrofa). We investigated whether this relatively high temperature influenced sow behavior and physiology around farrowing. One-half of 28 second-parity pregnant sows were randomly chosen to be exposed to floor heating 12 h after onset of nest building and until 48 h after birth of the first piglet (heat treatment), whereas the rest of the sows entered the control group (control treatment) with no floor heating. Hourly blood sampling from 8 h before and until 24 h after the birth of the first piglet was used for investigation of temporal changes in plasma concentrations of oxytocin, cortisol, and ACTH. In addition, occurrence and duration of sow postures were recorded -8 to +48 h relative to the birth of the first piglet. There was a clear temporal development in sow behavior and hormone concentrations (ACTH, cortisol, and oxytocin) across parturition (P < 0.001), independent of treatment. In general, hormone concentrations increased from the start to the end of farrowing. The observed oxytocin increase and peak late in farrowing coincided with the passive phase where sows lie laterally with an overall reduced activity. Floor heating increased the mean concentration of cortisol (P = 0.02; estimated as 29% greater than in controls) and tended to increase the mean concentration of ACTH (P = 0.08; estimated as 17% greater than in controls), but we did not find any treatment effect on mean oxytocin concentrations, the course of parturition, or the behavior of sows. Behavioral thermoregulation may, however, have lost some function for the sows because the floor was fully heated in our study. In addition, exposure to heat decreased the between-sow variation of plasma oxytocin (approximately 31% less relative to control) and ACTH (approximately 46% less relative to control). Whether this decreased variation may be indicative of acute stress or linked to other biological events is unclear. In conclusion, inescapable floor heating (around 33.5 degrees C) may be considered a stressor for sows around farrowing, giving rise to elevated plasma concentrations of cortisol, but without concurrent changes in oxytocin or behavioral activity.

Effects of percutaneous needle liver biopsy on dairy cow behaviour

In cattle, percutaneous needle liver biopsy is used for scientific examination of liver metabolism. The impact of the biopsy procedure is, however, poorly investigated. Our aim was to examine the behaviour of dairy cows during and after liver biopsy. Data were collected from 18 dry cows. Percutaneous needle liver biopsies (after administration of local anaesthesia (2% Procaine)) and blood samples were taken during restraining. During the control treatment, animals were restrained and blood sampled. During the biopsy procedure, cows showed increased restlessness (P=0.008), frequency of head shaking (P=0.016), and decreased rumination (P=0.064). After biopsies, tail pressing (P=0.016) and time spent perching (P=0.058) increased. Time spent upright (P=0.10) and number of leg movements (P=0.033) increased during the night as compared to controls. Thus, liver biopsy induced behavioural changes for up to 19 h--and particularly for behaviour previously associated with pain. Even though the exact welfare impact of percutaneous needle liver biopsies in cows is not known, and the magnitude of the behavioural changes was limited, pain always has negative effects on animal welfare. Therefore, if the present biopsy procedure--involving several biopsy passes--is to be used, improvement of the anaesthetic protocol as well as the inclusion of analgesics should be considered.

The effects of floor heating on body temperature, water consumption, stress response and immune competence around parturition in loose-housed sows.

The aim of the present study was to study whether floor heating from 12h after onset of nest building until 48 h after birth of the first piglet had any effect on measures related to body temperature, water consumption, stress response and immune competence in loose-housed sows (n=23). In conclusion, the present results indicate that floor heating for a limited period around parturition did not compromise physiological and immunological parameters, water intake and body temperature in loose-housed sows. The water intake peaked the day before parturition and the body temperature peaked on the day of parturition. A cortisol peak at parturition, a transient rise in the number of leucocytes and neutrophils and a transient reduction in the number of lymphocytes, erythrocytes and in the PCV value were observed. Around and after parturition some non-specific immunological variables seemed to be stimulated while others seemed to be compromised.

Effect of dietary protein levels on growth performance, mortality rate and clinical blood parameters in mink (Mustela vison)

Effects of dietary protein levels ranging from 35% to 15% of metabolizable energy (ME) and dietary fat levels ranging in a reciprocal fashion from 47% to 67% of ME, and a constant dietary carbohydrate level of 18% of ME were investigated in male mink kits in the growing‐furring period. Growth performance, mortality rate, hepatic fatty infiltration, weights of body and liver, relative weight of liver, haematocrit values, plasma activities of alanine‐aminotransferase (ALAT), aspartate‐aminotransferase (ASAT) and creatine‐kinase (CK), and plasma concentrations of chemical parameters were studied. A protein supply of 30% of ME supported normal growth performance and ensured a low mortality rate. Plasma ALAT and hepatic fatty infiltration increased with decreasing ME from protein. Alanine‐aminotransferase was found to be a useful tool in estimation of the incidence of hepatic fatty infiltration. The haematocrit values and the plasma values of total protein, urea, creatinine and bile acids were influenced by th...

Stress Physiological Status and Fur Properties in Farm Mink Placed in Pairs or Singly

Abstract The effects of keeping farm mink in pairs or singly from weaning to pelting on haematological, clinical-chemical and stress physiological variables, on body and organ weight, and on fur properties were examined in 96 mink kits in order to assess the consequences on welfare and productivity. Mink kept in pairs had better pelt quality than mink kept singly. No significant difference was found in frequency of hair chewing between mink in pairs and single mink. Bite marks on the leatherside of the pelt occurred only in mink kept in pairs. No significant difference was found between the groups in body weight, and organ weight corrected for body weight. Based on the physiological variables applied, no differences in welfare were shown between mink in pairs and single mink. Sexual differences were found for the enzymes ASAT and ALAT, for number of leucocytes, and for adrenal glands relative to body weight.

The effects of feed restriction on physical activity, body weight, physiology, haematology and immunology in female mink.

The aim of the present study was to investigate if adult mink females characterised as having a high or low residual feed intake (RFI) differed in their response to feed restriction with regard to activity, body weight loss and physiological parameters. For RFI-High, the activity was higher prior to the expected feeding time both in the cases of restrictive and ad libitum feeding indicating a changed RFI-High feeding motivation and a higher risk of developing stereotypic activity. The body weight gain and the feed consumption were higher for RFI-High than for RFI-Low when feeding ad libitum indicating that RFI-High has a higher growth potential and/or a higher energy requirement than RFI-Low. Signs of immunosuppression were shown in connection with restrictive feeding compared to ad libitum feeding, and RFI-High females seemed to be more susceptible to immunosuppression than RFI-Low females. Based on the present results, mink characterised as RFI-Low would be preferable as breeders because they involve lower feed costs and seem to be less susceptible to immunosuppression. They also seem to have less risk of developing stereotypic activity, which is beneficial for the welfare.

Priming the cow for lactation by rapeseed supplementation in the dry period

High-producing dairy cows experience a sudden and significant increase in energy requirements due to the onset of milk production in early lactation. They mobilize body reserves, mainly adipose tissue, resulting in an increased risk of production decline and the development of health disorders. The objective of the present study was to investigate the effects of feeding oilseeds (rapeseed) during the dry period, thereby priming dairy cows for metabolism of body fat in early lactation. Forty-three Holstein dairy cows were used, 14 were primiparous and 29 were multiparous (≥2 nd lactation). In the dry period, 8 wk before expected calving until calving, the cows were fed either a diet with a high content of rapeseed in the total mixed ration (HF) or a standard total mixed ration with a low content of fat (CON). During the first 5 wk after calving, all the cows were fed a standard low fat lactation ration. The treatments were evaluated by performance and metabolic variables in blood and liver. The dry period diet had no effects on body weight and body condition score of the cows during the dry period and in early lactation. The daily yield of milk, protein, and lactose did not differ among treatments. However, the milk fat concentration was lower and the daily milk fat production tended to be lower for the cows fed the HF diet in the dry period compared with the cows fed the CON diet. The plasma content of nonesterified fatty acids, cholesterol, and phospholipids in the dry period was increased in the HF dry period diet compared with the CON diet. The lower plasma concentration of uric acid obtained prepartum for the cows fed the HF diet may indicate a lower rumen microbial protein synthesis. Postpartum, the plasma concentration of β-hydroxybutyric acid tended to be lower for the cows fed the HF dry period diet. The liver content of triglycerides was lower and the liver content of glycogen was higher in early lactation among the cows fed the HF dry period diet compared with the cows fed the CON diet. Based on liver glycogen, triglyceride content, and blood β-hydroxybutyric acid concentration, it could be argued that intake of oilseeds during the dry period is a positive strategy for priming dairy cows for fat metabolism in the following early lactation.

Metabolomic study of plasma from female mink (Neovison vison) with low and high residual feed intake during restrictive and ad libitum feeding.

Metabolite profiling may elucidate changes in metabolic pathways under various physiological or nutritional conditions. In the present study two groups of female mink characterised as having a high (16 mink) or low (14 mink) residual feed intake were investigated during restrictive and ad libitum feeding. Blood samples were collected three times during the experimental period; during restrictive feeding, and four days and three weeks after the change to ad libitum feeding. Plasma samples were subjected to liquid chromatography mass spectrometry non-targeted metabolomics. Subjecting data to principal component analysis showed that there was no grouping of the data according to the residual feed intake. In contrast, data were clearly grouped according to feeding level. Identification of the metabolites responsible for this grouping showed that the plasma level of metabolites related to mobilisation of energy was high during restrictive feeding, e.g. betaine, carnitine, and creatine. During ad libitum feeding the plasma level of metabolites that can be characterised as biomarkers of meat intake (creatinine, carnosine, 1- and 3 methylhistidine) was high. The plasma level of lysophosphatidylcholine species was highest after four days of ad libitum feeding suggesting a short term imbalance in the transport or metabolism of these metabolites when changing the feeding level.

Effects of dietary protein level on growth, health and physiological parameters in growing-furring mink

The aim of the study was to investigate the effects of the dietary protein level and the feeding strategy on growth, health and physiological blood and liver parameters in growing-furring male mink. Effects of dietary protein levels ranging from 22 % of metabolizable energy (MEp) to 32 % of MEp were included in the study. The dietary protein levels were unchanged during the experimental period or reduced from a higher to a lower level in August or September. The results indicated negative effects on health and signs on immunosuppression in mink fed low dietary protein levels throughout the growing-furring period. The liver content of fat and fatty acids was higher in mink fed low dietary protein levels than in mink fed high dietary protein levels. The mortality rate was influenced of the dietary protein level in October.