Ovarian hypoplasia in heifers due to germ cell weakness.
Ovarian hypoplasia due to germ cell weakness was found in 18 heifers of the Swedish Red and White breed simultaneously with a sharp increase of the same syndrome in bulls of the same breed. The heifers were examined because they had not shown estrus or had not become pregnant after several months on pasture together with a fertile bull. After palpation of the ovaries per rectum they were classified as normal, partially hypoplastic or totally hypoplastic. The heifers were slaughtered and the numbers of primordial follicles were counted in the serially sectioned ovaries. The average numbers of follicles per ovary in the 3 diagnostic groups were 18716, 6617 and 4761, respectively. The numbers of primordial follicles in hypoplastic ovaries were significantly lower than in normal ovaries but were still within normal limits for heifers. However, the hypoplastic ovaries were very small, and the totally hypoplastic ones weighed only 1 g or less. The growth of the primordial follicles was disturbed and very few developed into Graafian follicles. There were also many empty cortical cords and anovular follicles. The heifers had all been sired by bulls belonging to breeding lines where germ cell weakness had occurred.
Infertility due to bilateral ovarian hypoplasia in sheep homozygous (FecXI FecXI) for the Inverdale prolificacy gene located on the X chromosome.
Ewes heterozygous (I+) for the Inverdale prolificacy gene (FecXI) located on the X chromosome have ovulation rates about 1.0 units higher than noncarriers. The purpose of this study was to examine the reproductive performance of ewes that were either heterozygous or homozygous (II) carriers of the Inverdale gene. Carrier rams (I) were mated with heterozygous ewes (I+) to produce females, half of which were expected to be I+ and half II. The 59 female progeny were examined by laparoscopy at 8 mo or 1.5 yr of age; 48% were found to have nonfunctional "streak" ovaries, which were about one eighth the volume of normal ovaries and showed no sign of follicular activity. There were four examples of full sib pairs where within each pair one had normal ovaries and the other had streak ovaries. Since these streak ovaries have not been observed in ewes known to be I+ or noncarriers (++), it is concluded that this condition is associated with animals homozygous for the Inverdale gene.
Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)
Based on the experimental studies, the process of ground regeneration around the borehole loaded with brine-water heat pumps working exclusively for heating purposes in the period of four consecutive heating seasons in a cold climate was presented. The research was conducted in north-eastern Poland. The aim of the work is to verify the phenomenon of thermal ground regeneration in the period between heating seasons on the basis of the recorded data and to check whether the ground is able to regenerate itself and at what rate. It was noticed that the ground does not fully regenerate, especially during heating seasons with lower temperatures. In the analyzed period, from 22 September 2016 to 12 October 2020, the ground probably cooled irreversibly by 1.5 °C. In order to illustrate and evaluate the speed of changes in the ground, the one’s profile with an undisturbed temperature field was presented for each month of the year. The presented results can be a very important source of information for the analysis of geothermal conditions occurring in the ground. They can be used to verify mathematical models and conduct long-term simulations that allow us to see the complexity of the processes taking place in the ground.