The Effect of Supplemental Lighting during the Late Gestation Period on Post-Partum Mechanical Properties of Mare and Foal Guard Hair.

This study investigates Thoroughbred mares exposed or not to supplemental blue light at the end of the gestation. Sixty mares and their 60 foals were selected for the investigation. Guard hair samples were collected from the shoulder just after (within 12 h) the parturition or birth. The foals of the light-treated mares developed significantly (p < 0.05) shorter hair than those of the control mares. A general effect of light treatment on basal hair diameter thinning could be demonstrated (p < 0.005). The maximum force of hair samples of light-treated mares and foals (0.098 and 0.085 N, respectively) was significantly lower than that of the control (0.272 and 0.178 N, respectively). The tensile strength (82.2 N/mm2) of the foal hair samples of the light-treated mares was significantly lower than that of the control foals (121.6 N/mm2). Although no significant difference was found in the elongation (ΔL), the hair of the control animals (mares and foals together) was more elastic than that of the treated animals (335 vs. 262 µm). In conclusion, the supplemental blue light treatment of the pregnant mares has a decreasing effect on both mares and their foals on the mechanical properties of the hair, making it shorter, thinner, and weaker.

Plasma melatonin concentration during the early post-partum period in Thoroughbred mares and their foals.

The authors aimed to determine the plasma melatonin concentration in mares and their new-born foals in the early post-partum period. Blood samples were collected from the jugular vein of 53 mare-foal pairs within twelve hours after parturition. Plasma melatonin levels were measured by ELISA. The melatonin concentration, adjusted for the moment of parturition using a generalised linear model, was 34.58 pg mL-1 in mares. It was significantly lower (27.63 pg mL-1) in the new-born foals. However, the melatonin concentration declined differently by the end of the twelve hours, it decreased less in the offspring than in the mothers. An artificial light supplementation at the end of gestation reduced the melatonin concentration both in mares and their foals by about 10 pg mL-1, compared to the controls. An elevated melatonin production may be related to preparation of mares for parturition and ensures the chances of survival of offspring, therefore the melatonin may reach its peak at the moment of foaling regardless of its actual time. The effect of low melatonin concentration in new-born foals might be associated with the foal's health and subsequent performance. The need to monitor the melatonin concentration in the offspring justifies further studies.

Electronic monitoring of rumination activity as an indicator of health status and production traits in high-yielding dairy cows.

In view of the demonstrated relationship between rumination time and health status, the general welfare and metabolic condition of ruminants are often assessed by the examination of rumen function. The main goal of this study was to monitor the daily rumination activity (RA) and its connection with actual liveweight (LW), milk yield (MY) and with two diseases (subclinical hyperketonaemia - SHK, uterine disease - UD) in 96 cows on the basis of a total of 1638 observations in Israel. The studied sample gave a highly significant response, showing that the selected diseases had a diminishing impact on RA and LW and no influence on MY. It can be concluded that the change of RA as determined by electronic monitoring, complemented by the change of LW, is a useful general indicator of health status and subclinical disease before the appearance of clinical signs.

Evaluation of mercury and lead content in the liver of the cormorant (Phalacrocorax carbo sinensis) population of Kis-Balaton, Hungary.

Mercury and lead concentrations were measured in the livers of cormorant (Phalacrocorax carbo sinensis), an aquatic bird species living and nesting in the special, highly protected nature conservation area of Kis-Balaton, Hungary. The measurements of metal concentrations were performed by atomic absorption spectrometry using the cold vapour method for mercury and the electrothermal method for lead. Mercury concentrations in the livers were significantly higher in the adult population (4.479 ± 3.336 mg/kg dry matter, DM) than in the juvenile birds (2.682 ± 2.087 mg/kg DM), indicating an increase of bioaccumulation with age. A similar pattern was not observed for lead. There were no statistical differences between males and females either in mercury or in lead concentrations. The average levels of mercury (3.580 ± 2.906 mg/kg DM) and lead (0.746 ± 0.499 mg/kg DM) were statistically different in the liver. No correlation was found between the concentrations of the two heavy metals. Recently, the wild birds have been chronically exposed to subtoxic amounts of metals which have a tendency to accumulate especially in the soft tissues.

Pathological changes induced by rancid feed in rats and effects on growth and protein utilisation.

The objective of this trial was to study the effect of rancid feeds on the health status and growth of rats and to determine the pathological changes induced by dietary rancidity. Forty-two weaned male rats (body weight: 69.3 +/- 1.0 g) were divided into seven experimental groups (n = 6 each). Rats in the different groups were fed diets containing meat-and-bone meal at an inclusion rate of 19 to 22%, low or high in peroxides and high in organic acids, with or without antioxidant. The diets were isoproteic (10%) and isolipidic (6%). During the 26-day-long trial (5 days for adjustment and 21 days for the main period) the body weight gain and the feed consumption were recorded. At the end of the trial detailed gross and histopathological examinations were performed. Feeding high-peroxide feed mixtures for 21 days significantly (P < 0.05) decreased feed intake and liveweight gain, while high organic acid concentration had only slight negative effects. Antioxidant supplementation alleviated the harmful effects, especially in the high-peroxide group. The ingestion of rancid feed mixtures and the subsequent decreased feed intake caused a decrease of glycogen content in the hepatocytes, accompanied by a slight centrolobular fatty infiltration. Peroxides caused lymphocyte depletion in the spleen, decreased the size of Malpighian bodies and the number of lymphoblasts, and altered the spermatogenesis. The protective effect of the antioxidant mixture seemed to be negligible in this respect.

Effects of high dietary molybdenum in rabbits.

To study the effects of high dietary molybdenum (Mo) content, rabbits were fed with commercial pellets and carrots containing 39 mg Mo/kg dry matter (DM) [Experiment 1] and with a commercial diet supplemented with 40 mg Mo/kg DM [Experiment 2] for 14 days. The high dietary Mo contents failed to reduce the growth performance of rabbits. Moreover, supplemental Mo given in a dose of 40 mg/kg non-significantly decreased the apparent digestibility of crude protein (CP) and crude fibre (CF) compared to the control (73.63 +/- 2.49 and 18.56 +/- 5.10 vs. 74.31 +/- 3.03 and 21.38 +/- 6.48, respectively). Molybdenum ingested with feeds was mainly excreted (57%) via the urine. The highest Mo levels were found in kidney and liver samples (3.464 +/- 0.872; 5.27 +/- 0.95 mg/kg DM [Experiment 1] and 1.878 +/- 0.283; 1.62 +/- 0.16 mg/kg DM [Experiment 2], respectively), and Mo could also be detected in limb meat (0.336 +/- 0.205 mg/kg DM). It was stated that the testes were more sensitive to Mo exposure than the female reproductive organs because the number of germ cells was reduced. Due to the high dietary Mo intake free radicals could be generated, resulting in a marked increase of creatine kinase (CK) activity.