Ultrastructural Changes in the Cyclic Corpus Luteum of Dairy Cows with Different Body Condition

Abstract

The aim of the study was to defi ne ultrastructural changes in the ovarian cyclic corpus luteum (CL) of dairy cows with different body condition score (BCS, a 5-point scale). The ovaries were recovered from slaughtered Holstein cows of BCS1 (emaciation; n= 4), BCS2 (tendency to emaciation; n=4), BCS3 (average body condition; n= 4), BCS4 (tendency to fattening; n=4) and BCS5 (fattening; n=4). Average ages of cows were: 6.2, 4.1, 5.7, 5.5 and 6.36 years for BCS1, BCS2, BCS3, BCS4 and BCS5, respectively. For electron microscopy, functioning CL at the mid-luteal phase were fi xed in the aldehyde solution and post-fi xed in 1% OsO4 solution. For lipid visualization the samples were soaked in 1% p-phenylenediamine solution in acetone. Durcupan ultrathin sections (90 nm) were contrasted with uranyl acetate and lead citrate and viewed under Jeol transmission electron microscope. Occurrence of cell organelles was determined by counting the relative volume of individual cellular components using the modifi ed universal test network. Luteal regression of cyclic CL was characterized by atrophy of lutein cells, condensation of organelles and cytoplasmic inclusions, increase in relative volumes of vacuoles, lysosomes, peroxisomes, autophagosomes and lipids. There were signifi cant differences (p<0.05) among BCS1, BCS2, BCS4 and BCS5 cows in the occurrence of lipids, vacuoles, lysosomes and autophagosomes in the lutein cells compared to BCS3 cows. Cows with BCS2 or BCS1 had higher relative volume of lipid droplets, whilst the BCS4 or BCS5 cows had increased occurrence (relative volume) of vacuoles, lysosomes, peroxisomes and autolysosomes. These results show that luteolysis of cyclic CL of cows has different patterns in each BCS group; in the emaciated and fattened cows luteolysis starts earlier than in cows with average body condition.

Comparison of service period and lactation milk yields in dairy cows with single- and twin-calving

“…As is well known, the length of the SP is multifactorial. It depends on hormonal status (Répási et al, 2014), level of milk production (Szelényi et al, 2015), involution disorders (Szenci et al, 2015), body condition (Pivko et al, 2016), metabolic status (Cicnović et al, 2017) and other reproductive features (Keary, 2017). The beta values (Table 2) are regression coefficients.…”

Functional and morphological maturation of the full-sized and mini-pig corpus luteum by programmed cell death mechanism

“…In the cell-death process, programmed death by autophagy is caused by irregular CL formation or physiological abnormalities in many mammalian animals. Thus, it is possible to evaluate the physiological phenomenon caused by hormone action according to the formation of the corpus luteum (1,20). We analysed the corpus luteum of Yorkshire pigs and mini-pigs in the middle stage of the oestrous cycle, which is considered to have the highest steroidproducing activity and CL function.…”

“…Ultimately, apoptosis-induced CL cell death is the basis of the structural degeneration process (25). Importantly, recent studies in rodents (4) and cattle (20) indicated that programmed cell death participates in CL regression (13). Taken together, the results of previous studies suggest that there may be differences in the apoptosis process depending on the pig breed, which may differentiate the structural changes of the CL during oestrus and gestation in pigs.…”