Past studies suggested that during early lactation and the transition period, higher plasma growth hormone (GH) levels in subclinical ketosis (SCK) might involve the initiation of body adipose tissues mobilization, resulting in metabolic disorders in ruminants particularly hyperketonemia. The upregulated GH mRNA expression in adipose tissue may take part in the adipolysis process in SCK-affected cows that paves a way for study further. This study aimed to characterize the plasma levels of GH, β-hydroxybutyrate acid (BHBA) and non-esterified fatty acid (NEFA) and glucose (GLu) in ketotic cows and healthy control (CON) cows; to measure the liver function test (LFT) indices in ketotic and healthy CON cows, and finally the quantitative real-time PCR (qRT-PCR) assay of candidate genes expressed in adipose tissues of ketotic and healthy CON cows during 0 to 7 week postpartum. Three experiments were conducted. Experiment-1 involved 21 Holstein cows weighing 500–600 kg with 2–5 parities. Results showed that GH, BHBA, and NEFA levels in ketotic cows were significantly higher and the GLu level significantly lower. Pearson's correlation analysis revealed a significant positive correlation of GH with BHBA, NEFA, and GLu in ketotic and healthy CON cows. In experiment-2, dynamic monitoring of LFT indices namely, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (GGT), total bilirubin (TBIL), direct bilirubin (DBIL), total protein (TP), albumin (ALB), globulin (GLOB) and albumin/globulin (A/G) were examined. The TBIL, DBIL, and GGT indices were significantly higher in ketotic cows and TP was significantly lower. In experiment-3, mRNA expression levels of GHR and peroxisome-proliferator-activated receptor alpha (PPARα) genes in adipose tissue were significantly upregulated in ketotic cows. However, the mRNA expression of insulin-like growth factor-I (IGF-1), insulin-like growth factor-I receptor (IGF-1R), and sterol regulatory element-binding protein-1c (SREBP-1c) genes in adipose tissue were downregulated in ketotic cows. Our study concluded that during postpartum, higher plasma GH levels in SCK cows might involve the initiation of body adipose tissue mobilization, resulting in hyperketonemia.
Heat stress is a major threat to cattle reproduction today. It has been shown that the effect of high temperature not only has a negative effect on the hormonal balance, but also directly affects the quality of oocytes, disrupting the function of mitochondria, fragmenting their DNA and changing their maternal transcription. Studies suggest that the induction of HSP70 may reduce the apoptosis of granular layer cells caused by heat stress. It has been shown that the changes at the transcriptome level caused by heat stress are consistent with 46.4% of blastocyst development disorders. Cows from calves exposed to thermal stress in utero have a lower milk yield in their lifetime, exhibit immunological disorders, have a lower birth weight and display a shorter lifespan related to the expedited aging. In order to protect cow reproduction, the effects of heat stress at the intracellular and molecular levels should be tracked step by step, and the impacts of the dysregulation of thermal homeostasis (i.e., hyperthermy) should be taken into account.
It is a well-known fact that the reproductive organs in women, especially oocytes, are exposed to numerous regulatory pathways and environmental stimuli. The maternal age is one cornerstone that influences the process of oocyte fertilization. More precisely, the longer a given oocyte is in the waiting-line to be ovulated from menarche to menopause, the longer the duration from oogenesis to fertilization, and therefore, the lower the chances of success to form a viable embryo. The age of menarche in girls ranges from 10 to 16 years, and the age of menopause in women ranges from approximately 45 to 55 years. Researchers are paying attention to the regulatory pathways that are impacting the oocyte at the very beginning during oogenesis in fetal life to discover genes and proteins that could be crucial for the oocyte’s lifespan. Due to the general trend in industrialized countries in the last three decades, women are giving birth to their first child in their thirties. Therefore, maternal age has become an important factor impacting oocytes developmental competence, since the higher a woman’s age, the higher the chances of miscarriage due to several causes, such as aneuploidy. Meiotic failures during oogenesis, such as, for instance, chromosome segregation failures or chromosomal non-disjunction, are influencing the latter-mentioned aging-related phenomenon too. These errors early in life of women can lead to sub- or infertility. It cannot be neglected that oogenesis is a precisely orchestrated process, during which the oogonia and primary oocytes are formed, and RNA synthesis takes place. These RNAs are crucial for oocyte growth and maturation. In this review, we intend to describe the relevance of regulatory pathways during the oogenesis in women. Furthermore, we focus on molecular pathways of oocyte developmental competence with regard to maternal effects during embryogenesis. On the background of transcriptional mechanisms that enable the transition from a silenced oocyte to a transcriptionally active embryo, we will briefly discuss the potential of induced pluripotent stem cells.
Mineral deficiencies are a common problem in dairy herds around the world. Currently, they most often occur in a subclinical form or with atypical symptoms, which makes their diagnosis difficult. New methods and possibilities of identifying mineral deficiencies are being sought. Hematological changes may occur in the early stages of the development of deficiency diseases, and their detection may be helpful in the early diagnosis of diseases. The aim of the article is to present the most important information on disorders in the red blood cell system in the course of mineral deficiencies in dairy cattle. Hematological tests should become one of the most important elements facilitating the determination of the health condition of cows and enabling the correct diagnosis and therapy of cattle diseases. Copper, iron, magnesium and phosphorus deficiencies cause changes in hematological parameters. In iron and copper deficiency, there are microcytic, hypochromatic or normocytic, normochromic anemia. On the other hand, in the deficiency of magnesium and phosphorus, there is normocytic, normochromic anemia.
The aim of the study was to determine the effect of heat stress on differences between selected biochemical blood parameters in cows in June and October, taking into account different housing systems and cooling systems used. The research was carried out on 60 cows from stanchion barns (farm A) and loose-house barns (farm B). Material for research, venous blood, was collected at the same time, in the morning, after milking and clinical examination. Then, parameters describing the energy balance and the activity indexes of the parenchymal organs as well as the mineral balance were determined. Milk production in both farms was clearly lower in June than in October, but the difference between milk yields obtained from the two farms was over 15% in June and only less than 10% (5-6 kg of milk) in October. Both farms A and B showed an increase in aspartate aminotransferase and creatine kinase. In farm A, the statistically significant increase exceeded the normal physiological range, which could indicate developing disturbances in the locomotor system caused by the impact of high temperature. Energy balance disturbances occurred only in farm A, where a statistically significant decrease in glucose and cholesterol concentration was found in June samples, which, according to the authors, could be related to a higher energy demand. The results of biochemical tests of venous blood collected in June may indicate the onset of fatty liver in cows (decreased cholesterol, glucose, and total protein levels, as well as increased bilirubin levels and GGTP activity) as a consequence of exposure to high temperatures. Heat stress has a significant impact on the functioning of the cow’s organism, which will not always be manifested by characteristic clinical signs. Accurate laboratory analyses make it possible to diagnose changes developing as a result of cows being exposed to heat stress.
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