Night-time Melatonin Secretion and Seasonally Delayed Puberty in Gilts

This study was conducted to determine whether the seasonal delay in puberty in autumn is driven by individual differences in night-time melatonin secretion in domestic gilts at the attainment of puberty. A group of spring-born gilts (n = 30) were expected to reach puberty in autumn by the age of 7 months. Eighteen of these gilts were selected in pairs on the basis of matched days of birth. By the expected time, half of the animals showed oestrous symptoms (group CYCLING, n = 9) with the rest remaining silent (group SILENT, n = 9). Afterwards, all gilts were fitted with indwelling jugular catheters for frequent blood sampling. Blood samples were collected from all animals three times during the day followed by three times in the night at 2-h intervals for 48 h. The samples were analysed by a commercial radioimmunoassay (RIA). The results show a consistent 25-fold rise (on average) in night-time melatonin concentration in every animal sampled with group averages ranging from 0.28 +/- 0.04 to 0.37 +/- 0.06 pg/ml at day and from 10.20 +/- 2.16 to 10.67 +/- 0.05 pg/ml at night. Night-time group mean values between CYCLING and SILENT gilts did not differ significantly (10.26 +/- 0.67 and 10.38 +/- 0.94 for the CYCLING; 10.67 +/- 0.05 and 10.20 +/- 2.16 for the SILENT). When 10 pg/ml was used as a threshold value, six individuals did not reach it during the night (low responders). Two of these gilts were CYCLING and four were SILENT. In conclusion, the results presented imply no involvement of the level of night-time melatonin concentration in the seasonal delay of puberty in gilts.     

Energy and protein metabolism in pregnant sows fed two levels of dietary protein

The present study was performed to quantify the energy and nutrient metabolism of pregnant sows fed high (HP) or low (LP) dietary protein [18.3 vs. 13.5% of dry matter (DM)]. A total of nine sows (four on HP and five on LP diet) were subjected to balance and respiration trials four times during their second pregnancy (approximately on days 30, 61, 80 and 104 of gestation). The digestibility of protein (83.0 vs. 79.9) (p < 0.01) and energy (84.9 vs. 83.7%) (p < 0.05) was higher for the HP diet. Daily intake of metabolizable energy (ME) and retained energy (RE) were similar for the two groups, with an average of 28.37 MJ ME and 3.94 MJ RE, respectively. Heat production (HE) measured according to the respiratory quotient (RQ) and carbon-nitrogen (CN) method was similar (464 vs. 454 kJ/kg 0.75/day, respectively). Sows fed HP retained more energy in protein (3.33 vs. 2.00 MJ/day) (p < 0.001) and tended to retain less energy in fat (1.59 vs. 2.50 MJ/day) than LP sows. Retained nitrogen (N) (22.3 vs. 13.4 g/day) (p < 0.001) and utilization of N (retained/digested) (45.2 vs. 38.1%) was higher for HP sows compared with LP sows. In late pregnancy, retained N, retained fat, HE and oxidation of carbohydrates increased, while oxidation of fat was reduced to zero. In conclusion, both diets provided adequate N for retention in maternal tissue and conception products. In spite of the lower utilization of N in LP sows, the N excretion was depressed by 5.6 g/day compared with HP sows, because of the lower N intake.     

Factors Affecting Fertility in Loosely Housed Sows and Gilts: Vulvar Discharge Syndrome, Environment and Acute-phase Proteins

The effect of vulvar discharge syndrome (VDS) on sow and gilt fertility was studied on 26 farms. Of 824 animals inspected in 21 randomly selected and five VDS problem farms, 19 (2.3%) were afflicted with VDS. Altogether 542/799 of the examined animals (67.8%) farrowed thereafter. Nine of the 19 VDS animals (47.4%) and 533/780 non-VDS animals (68.3%) farrowed at the first chance after the examination (p = 0.05). None of the unmated gilts in this study had VDS. Environmental and individual factors likely to be associated with fertility and VDS were tested. In multivariate analysis, factors associated with farrowing were VDS, reproductive status, availability of roughage and confinement to individual stalls. None of the variables tested was associated with VDS. However, all of the VDS problem farms were overcrowded and had concrete, partly slatted floors with little or no bedding. The median value of haptoglobin (Hp) was 2.5 (range 1.3-3.1) g/l in VDS animals and 2.3 (0.5-4.3) g/l in controls (p = 0.6). The median C-reactive protein (CRP) in VDS animals was 30.3 (3.3-171.3) mg/l and in controls 25.9 (3.3-361.1) mg/l (p = 0.7). In conclusion, VDS decreased fertility of gilts and sows in the absence of a systemic acute-phase response, as indicated by stable concentrations of Hp and CRP.     

A method for identification and mapping potentially acid sulfate soils in Jutland, Denmark

A method for mapping potentially acid sulfate soils in Jutland, Denmark is described. First the wetlands were outlined, using already existing topographic maps. Then 7900 profiles, evenly distributed over the wetland areas, were examined to point out areas with potentially acid sulfate soils. The method used to identify potentially acid sulfate material was, for carbonate-free samples, a pH-measuring at the sampling time and after the samples were inoculated with soil water extract from an acid sulfate soil and 2, 8 or 16 weeks of incubation. For carbonate-containing samples the pyrite content was compared to the acid-neutralizing capacity. A map was constructed showing the ratio of profiles containing potentially acid sulfate soil samples to total number of profiles examined within natural geographical wetland regions.The investigation showed that 35% of the wetlands in Jutland have a high frequency of potentially acid sulfate soils.     

Estimation of quantitative oxidation and fat retention from carbohydrate,protein and fat in growing pigs

Die Oxidation von Nährstoffen und Retention von Kohlenhydraten, Protein und Fett hei wachsenden Schweinen Die Oxidation von Nährstoffen sowie deren Beitrag zur Fettretention wurde an Hand von 185 individuellen Bilanzstudien mit wachsenden Schweinen (40–100 kg Lebendgewicht) beurteilt. Der Respirationskoeffizient ohne Berücksichtigung des Proteins (RQnp) lag entweder unter oder über 1. Die beschriebene Methode basierend auf Gasaustausch sowie Kohlenstoff-Stickstoffbilanz zur Berechnung der Oxidation von Nährstoffen und Lipogenese ist in beiden Fällen gültig (RQnp > 1 und RQnp < 1). Bei einer den Wachstumsbedarf deckenden Energiezufuhr (ME ≥ 1,2 MJ/kg^0.75) ist die Oxidation von Nährstoffen im Bezug auf die Proteinretention abhängig von der Menge und Qualität des verdauten Proteins. Weiterhin besteht eine Abhängigkeit von der Menge an verdaulichen Kohlenhydraten. Die Versorgung mit Fett spielt dagegen keine Rolle. Die Oxidation von Kohlenhydraten trägt mit 85%, die von Protein mit 15% zur anfallenden Wärmeenergie bei. Eine Fettoxidation findet auch bei hohem Fettgehalt der Nahrung nicht statt. Die Lipogenese aus Kohlenhydraten stellt die Hauptquelle für die Körperfettretention dar. Da keine Fettoxidation stattfindet, wird das gesamte Nahrungsfett im Körper reteniert. Bei einer für das Wachstum zu geringen Energiezufuhr werden Nahrungsfett und Körperfett oxidiert. Um Protein für die Retention zu erhalten, ist die Oxidation von Protein vermindert. Selbst bei Mobilisierung von Körperfett und Oxidation von Nahrungsfett wird ein Teil der Kohlenhydrate und des Proteins für die Lipogenese vermutlich zum Aufbau von Strukturfett verwendet.     

Evaluation of auditory evoked potentials to predict depth of anaesthesia during fentanyl/fluanisone−midazolam anaesthesia in rats

Objectives To assess a method for monitoring depth of anaesthesia using components of middle latency auditory evoked potential (AEP) waveforms during anaesthesia with fentanyl/fluanisone and midazolam. Study design Prospective observational study. Animals Five female Wistar rats weighing between 210 and 250 g. Methods Implanted electrodes were used to record AEPs in animals receiving five doses of anaesthetic. Recordings were made at 5 minutes post‐injection (deep anaesthesia; no pedal withdrawal response, PWR) and then at 25 minutes (light anaesthesia; strong PWR). Responses showed five characteristic peaks occurring at 11, 14, 23, 42 and 68 ms that were measured for latency of occurrence and peak amplitude. Results Auditory evoked potential peaks P14, N23 and P42 were increased significantly in latency with successive anaesthetic injections [avg. F(1,4) = 12.53, p < 0.001; avg. F(1,4) = 10.6, p < 0.001; avg. F(1,4) = 3.9, p = 0.02, respectively]. Peak N23 showed a significant reduction in latency during the 20 minute recovery period following both the first and second anaesthetic injections (t(3) = 7.52, p = 0.005; t(4) = 5.17, p = 0.007, respectively). Peak P42 occurred significantly earlier 20 minutes following the second anaesthetic injection (t(4) = 4.75, p = 0.009). The mean overall depth of anaesthesia assessed using PWR scores was significantly correlated with the mean latency of peak N23, such that as the strength of PWR increased, N23 occurred significantly earlier (r = ?0.99, p = 0.01). The amplitude difference between peaks N23 and P42 increased after the second and third drug administrations [avg. F(1,4) = 10.65, p = 0.031 and avg. F(1,4) = 11.24, p = 0.028, respectively]. Conclusion The characteristics of these peaks, and in particular latency of peak N23, may provide a useful tool for assessing depth of anaesthesia produced by this, and possibly other anaesthetic agents.     

Dietary structured lipids for post-weaning piglets: fat digestibility, nitrogen retention and fatty acid profiles of tissues

In four groups of post-weaning piglets the effects of triacylglycerol structure and fatty acid profiles of four dietary fats on apparent faecal nutrient digestibility, nitrogen retention and fatty acid profiles of platelet and erythrocyte membranes, liver, adipose tissue and skeletal muscle were examined. Dietary fats included as 10% (w/w) of the diets were two structured fats of rapeseed oil interesterified with tridecanoin (R1) or coconut oil (R2), respectively, one mixture of rapeseed oil and coconut oil (R3) and rapeseed oil as control (R4). Faeces and urine from piglets weaned at 28 days of age were collected quantitatively during three periods each of 5 days, in which the piglets were kept in metabolism cages for measurement of apparent faecal nutrient and energy digestibility and nitrogen retention. Apparent faecal fat digestibilities were significantly improved in groups fed interesterified fats or the physical mixtures (R1, R2 and R3) compared with rapeseed oil (R4). Apparent faecal nitrogen digestibility and retention were similar in all four groups in the three periods, but increased with time. Apparent faecal fat digestibilities were significantly improved from the first to the third week in the groups R1 and R2. Fatty acid profiles in platelet and erythrocyte membranes and in tissues reflected the fatty acid profile of the dietary fat, except for medium-chain fatty acids, which were only found in low proportions, indicating that 10:0 was mainly used as an energy source.