No abstract

Protein bound iodine (PBI) and total cholesterol levels in serum were determined from 589 arterial samples of healthy dairy cows in different stages of lactation during a period of 18 months. PBI values varied from 2.10 to 6.29 ɣ %, with approximately 79 % of the cases occurring between 3 and 5 ɣ % and the average PBI level being 3.935 ɣ %. Cholesterol values varied from 37.6 to 494.4 mg %, with approximately 66 % of the cases between 100 and 300 mg % and the average colesterol level being 197.43 mg %. The stage of lactation had a greater influence on total cholesterol level than on PBI level. PBI level was lowest one month post partum (3.65 ± 0.08 ɣ %), but remained rather constant from the 5th to 13th month post partum, varying between 3.96 ± 0.08 and 4.11 ± 0.08 ɣ %. It was assumed that during the early stages of lactation the disappearance of thyroid hormones from the serum may be somewhat faster than their synthesis within the thyroid gland, and after an adaptation period in the later stages of lactation, the thyroid gland is able to maintain an optimal PBI level in the serum. The average cholesterol level of 177 mg % one month post partum was relatively low in regard to milk production compared with cholesterol levels obtained at later stages of lactation. The relatively low cholesterol values in the early part of lactation may have reflected a state of physiological undernutrition or an adaptation of the liver and rumen to increasing milk production. The total cholesterol was parallel with milk production from the 3rd to 13th month post partum. The lowest cholesterol values occurred in the serum of dry cows. Significant seasonal variations were noticed in PBI and cholesterol levels. The highest average PBI levels were obtained in April, May, and June and the lowest at the end of July and at the beginning of August. The cholesterol levels were highest during the indoor feeding period from December to May and lowest during the pasture feeding period. Since seasonal variations of total cholesterol level resembled greatly those of PBI, it was assumed that there are common factors influencing simultaneously both the PBI and cholesterol levels.

Abstract. The rumen microbiota were studied in free-ranging semi-domestic reindeer in Finnish Lapland under the nutritional conditions obtaining at two different sampling times. Qualitative and quantitative investigations were made of the rumen ciliate fauna and quantitative investigations of the rumen bacterial flora. The volume coefficients for rumen ciliates obtained by Westerling (1970) and that for rumen bacteria obtained by Warner (1962) were used to obtain an indication of the volume of the rumen microbe mass in reindeer.The rumen samples were collected in connection with the round-up and slaughter of reindeer, being taken from 30 animals in December and 29 animals in March. The reindeer slaughtered in December had normal access to food,but those slaughtered in March had grazed on better pastures and received a supplementary feed of hay.The total number of ciliate cells was over six times as high in March as in December, the numbers being 1 182 900 and 188 300 per ml rumen contents, respectively. The corresponding total numbers of bacterial cells were 9.65 x 10 9 in March and 6.65 x 10 9 in December. The reason for the statistically significantly (P < 0.01) higher numbers in March than in December is probably the better nutritional conditions of the herd slaughtered in March, not the time of the year.The ciliate fauna consisted of 19 different species, although not all the species were found in every sample. The percentage composition of the ciliate fauna did not vary considerably between the two sampling times.The volume of the total microbe mass constituted 8.2% of the rumen contents in March and 1.9 % in December, the average being 5.1 %. The proportion of the ciliate volume in the total microbe mass was clearly higher than that of the bacteria at both sampling times: 7.2 times as high in March and 1.7 times in December, the average being 4.7 times.Since the importance of the rumen microbiota for the utilization of food by ruminants was established, many investigations have been made of the numbers and kinds of rumen microorganisms and the factors affecting them (Warner 1965, Hungate 1966. The majority of the studies have been devoted to the rumen microbiota of domestic animals, but some have also dealt with semi-domestic or wild animals (Giesecke 1970). An extensive review of the

In 1968, thyroid glands were obtained from young dairy animals born and raised in the areas of various Agricultural Societies of Finland. Breed, sex and carcass weight were recorded for each case. The thyroids were weighed and preparations made for the histological examination. The relative proportions of epithelium (E %), colloid (C %) and stroma (S %), and the height of the epithelial cells (Eμ), were estimated with histometric methods, and the absolute amount of epithelial tissue in grams per gland (Eg) was calculated. The relative size of the follicles (FN) was also determined. The glands were classified, on the basis of prevailing histological characteristics, into activity groups indicated by numbers from 1 (low) to 6 (high). The glands in groups 5 and 6 were considered histologically as abnormal. The data included both Ayrshires (375 ♂ and 239 ♀) and Finncattle (276 ♂ and 234 ♀), and was characterized by the following mean and range values: carcass weight 66.6 kg (7—214), thyroid weight 12.95 g (2.1—130.0), E % 26.1 (14.4—88.2), C % 70.2 (4.1—85.1), S % 3.7 (0.9—14.6), Eμ 5.0 (2.2—22.5), Eg 3.77 (0.44—98.15), FN 21.9 (9.0—84.7), histological activity 3.0 (1—6). Data obtained from the Ayrshire herd of the Viik Experimental Farm was used as a control material for this study. The correlation study revealed that breed and sex had very little effect on the various thyroid characteristics. Carcass weight, on the other hand, correlated significantly with all other thyroid characteristics except the E %. In order to evaluate the geographic distribution of goitre the data was divided into 15 groups according to the Agricultural Society in whose area the animals were born and raised. Effect of carcass weight on the weight, Eg, and histological activity of the thyroid was first eliminated (e.g. by calculating the deviations from the respective control values) before the 15 groups were comparable with each other. Investigations revealed that the thyroid weight, Eg, and E % were raised and the percentage of histologically abnormal glands was high in the Agricultural Societies of the District of Nyland & Nyland’s Swedish, the District of Tavastland, East-Tavastland, the District of Mikkeli, and North-Karelia. On the other hand, hardly any or no signs of goitre were found in the Agricultural Societies of Satakunta, Tavastland-Satakunta, and Kuopio. Attention was also paid to the consumption of iodized mineral salt mixtures by cattle in the various Agricultural Societies. The extent of variation found in the consumption rate was not, however, large enough to explain satisfactorily the differences in the goitre incidence. Since the mean consumption rate in whole Finland in 1967 was only 1/3 of that of the control herd, it is concluded that the amounts of supplemental iodine in the cattle rations should be considerably increased.

A reciprocal relationship occurs between the level ofthyroxine in blood and the intensity of TSH secretion from the anterior pituitary. If the synthesis and release of thyroxine within the thyroid gland is in some manner (as a result of iodine deficiency, goitrogens, enzyme defects) inhibited or retarded, the blood thyroxine level will eventually decrease and, as a consequence, the TSH release rate from the pituitary will increase above normal. This, in turn, results in hypertrophy and hyperplasia of the thyroid. Under these conditions a hyperplastic thyroid may prove to be an indicator of an inadequate rather than an increased thyroxine secretion rate. It is known that thyroxine is essential in maintaining efficient milk secretion (Turner 1968). Furthermore, it is quite possible that a greatly increased TSH secretion may interfere with the synthesis and release of other anterior pituitary hormones needed for maintaining an optimal secretion of milk.Swett et ai. (1955, p. 31) observed significant positive correlation between the relative thyroid weights and the milk and butterfat yields in Jerseys but not in Holsteins and Guernseys. In the study of Kossila (1967, p. 73), the thyroid weight of the cows was positively and significantly correlated with the body weight and age, while it was negatively and nonsignificantly correlated with the milk yield, when the body weight and age were held constant. However, compared to the weight of the thyroid, the epithelial tissue content of the gland is probably a more reliable indicator of the thyroxine secretion rate or of the intensity of the TSH stimulation on the thyroid gland (Tala 1952, Uotila & Kannas 1952, Lamberg 1953. The purpose of this study was to find out whether there were any significant correlations between the absolute amount of epithelial tissue contained in the thyroid gland of the cows and their body weight, age, and capacity of milk production.