Dorit Kalo

Dorit Kalo
Hebrew University of Jerusalem | HUJI · Department of Animal Sciences

PhD

About

34
Publications
2,555
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389
Citations
Additional affiliations
November 2011 - present
Hebrew University of Jerusalem
Position
  • Laboratory Manager

Publications

Publications (34)
Article
Full-text available
One major cause of low fertility of cows in the summer is progesterone deficiency. We found that insertion of a controlled intravaginal drug‐releasing (CIDR) device containing progesterone after artificial insemination (AI) increases pregnancy per AI (P/AI) in cows with uterine disease and low body condition score after calving. Here we treated onl...
Article
Full-text available
The impact of omega-3 nutritional manipulation on semen cryosurvival and quality post thawing is controversial. Our aim was to examine how feeding bulls with omega-3 supplementation from different sources affects the spermatozoa quality parameters. Fifteen Israeli Holstein bulls were fed for 13 weeks with a standard ration top-dressed with encapsul...
Article
Full-text available
An association between progressive motility (PM) and spermatozoa fertility competence has been suggested. However, the mechanism that underlies PM is not clear enough. We examined physiological characteristics and fatty acid composition of fresh spermatozoa with high and low PM. Additional analysis of fatty acid composition and structural character...
Article
Full-text available
We examined gonadotropin-releasing hormone (GnRH) administration at onset of estrus (OE), determined by automatic activity monitoring (AAM), to improve fertility of dairy cows during the summer and autumn. The study was performed on two dairy farms in Israel. The OE was determined by AAM recorded every 2 h, and a single im dose of GnRH analogue was...
Preprint
Spermatozoa progressive motility is positively correlated with fertilization competence. Bulls' ejaculates with progressive motility lower than 50% are routinely rejected through the process of straw preparation, designated for artificial insemination of dairy cows. We examined the quality and fertility competence of ejaculates with relative low pr...
Article
Full-text available
Atrazine (ATZ) is an extensively used herbicide and ubiquitous environmental contaminant. ATZ and its metabolite, diaminochlorotriazine (DACT), cause several cellular and functional alterations in spermatozoa. We aimed to examine the effect of ATZ/DACT on spermatozoon DNA integrity, fertilization competence, embryonic development and transcriptome...
Article
Heat stress is associated with increased production of reactive oxygen species (ROS) and disruption of bovine oocyte function. Here, we examined whether the antioxidant melatonin can alleviate the deleterious effects of heat stress on oocyte developmental competence. Cumulus-oocyte complexes were matured for 22 h at 38.5 °C (control) or for 22 h at...
Article
Breeding programs in farm animals has led to significant improvement in milk production. but not in fertility, most likely due to the complexity and the low heritability of fertility associated traits, known to be affected by multiple environmental and genetic variables. In light of the heterogeneity of fertility associated traits, studying the pro...
Article
Full-text available
Endocrine-disrupting compounds (EDCs) and foodborne contaminants are environmental pollutants that are considered reproductive toxicants due to their deleterious effects on female and male gametes. Among the EDCs, the phthalate plasticizers are of growing concern. In-vivo and in-vitro models indicate that the oocyte is highly sensitive to phthalate...
Article
This study aims to evaluate the deleterious effect of the mycotoxin aflatoxin B1 (AFB1) on bull spermatozoa and the carry-over effect on the developing embryo. Proteomic analysis of AFB1-treated spermatozoa revealed differential expression of proteins associated with biological processes and cellular pathways that involved in spermatozoon function,...
Article
Intensive reproductive management in dairy herds is mostly based on AI using high-merit bulls. Therefore, semen quality of bulls is of high importance. An association between semen quality and fatty acid content in feed has been suggested. Accordingly, the aim of this study was to examine the effect of omega-3 supplementation on sperm traits and fe...
Article
Mastitis has deleterious effects on ovarian function and reproductive performance. We studied the association between plasma or follicular fluid (FF) obtained from endotoxin-induced mastitic cows, and oocyte developmental competence. Lactating Holstein cows were synchronized using the Ovsynch protocol. On Day 6 of the synchronized cycle, an additio...
Article
Mono(2-ethylhexyl)phthalate (MEHP), the main di(2-ethylhexyl)phthalate (DEHP)metabolite, is a known reproductive toxicant. Residual levels of 20 nM MEHP have been found in follicular fluid aspirated from IVF-treated women and DEHP-treated animals. The current study examined whether these residual MEHP levels have any effect on the follicle-enclosed...
Article
Exposing bovine cumulus-oocyte complexes (COC) to heat shock during in vitro maturation (IVM) reduces oocyte developmental competence. Melatonin has been reported to improve cleavage of heat-shocked oocytes after fertilization. The current study examined whether protective activity of melatonin is associated with nuclear or cytoplasmic maturation e...
Article
Full-text available
PurposeThis paper reports the use of a novel automatic vitrification device (Sarah, Fertilesafe, Israel) for cryopreservation of oocytes and embryos. Methods Mice oocytes (n = 40) and embryos (8 cells, n = 35 and blastocysts, n = 165), bovine embryos (2PN, n = 35), and MII oocytes (n = 84) were vitrified using this automated device. A total of 42 (...
Article
Di-(2-ethylhexyl) phthalate and its metabolite, mono-(2-ethylhexyl) phthalate (MEHP), are reproductive toxicants. We recently documented a residual concentration of MEHP (~20 nM) and a 2-fold lower level of oestradiol in preovulatory-follicular fluid aspirated from cows gavaged with di-(2-ethylhexyl) phthalate (100 mg/kg/day; 3 days). To examine th...
Article
Di-(2-ethylhexyl) phthalate (DEHP) and its metabolite, mono-(2-ethylhexyl) phthalate (MEHP), are reproductive toxicants. However, disruptive effects of MEHP at low concentrations on the oocyte and developing blastocyst are unknown. Previously, we detected low levels of MEHP in follicular fluid aspirated from DEHP-treated cows associated with reduce...
Article
We examined acute exposure of Holstein cows to di(2-ethylhexyl) phthalate (DEHP) and its carryover effects on ovarian function and oocyte developmental competence. Synchronized cows were tube-fed with water or 100 mg/kg DEHP per day for 3 days. Blood, urine and milk samples were collected before, during and after DEHP exposure to examine its cleara...
Article
Subclinical chronic mastitis was induced to examine the effects on oocyte developmental competence. Uninfected Holstein cows were intramammary administrated with serial (every 48h for 20 days) low doses of toxin of Staphylococcus aureus origin (Gram-positive; G+), endotoxin of Escherichia coli origin (Gram-negative; G-) or sterile saline (control)....
Article
Summary We examined the association between progressive motility of spermatozoa and in vitro fertilization (IVF) competence of bovine ejaculates. Fresh semen was evaluated using a computerized sperm quality analyzer for bulls using progressive motility as the primary parameter. Ejaculates with high progressive motility (HPM; >81%) were compared wit...
Article
Di-(2-ethylhexyl) phthalate (DEHP) and its metabolites are environmental toxicants that potentially affect mammalian health. However, their effects on ovarian function, and in particular oocyte developmental competence, are less known. We established a model of acute exposure to DEHP to examine its immediate and long-term effects on follicles and o...
Article
Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer. Its metabolites have been shown to have adverse effects on reproduction and development in laboratory animals. However, the mechanisms by which they induce infertility remain elusive. We established an experimental model in which lactating Holstein cows were synchronized (GnRH-PG-Gn...
Article
Mastitis is associated with decreased fertility in dairy cows. In the current study we created an experimental model to simulate short-term mastitis by a single intramammary administration of Gram-negative endotoxin of E. coli origin (G-), or Gram-positive toxin of Staphylococcus aureus origin (G+), to examine the effect of mastitis on oocyte devel...
Article
We examined the effects of naturally occurring mastitis on bovine oocyte developmental competence in vitro. Specifically, we investigated the effects of intramammary infection on the ovarian pool of oocytes (i.e., follicle-enclosed oocytes) and their ability to undergo in vitro maturation, fertilization, and further development to the blastocyst st...
Article
In the last decade, potential exposure of humans and animals to industrial chemicals and pesticides has been a growing concern. In the present study, di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) were used to model the effects of endocrine-disrupting compounds and their risk in relation to early embryonic losses. Expos...
Article
Programmed cell death via the sphingomyelin pathway has been suggested to underlie heat-shock disturbance of oocyte developmental competence. A series of experiments were performed to characterise the role of the sphingolipid ceramide in heat-shock-induced apoptosis, and to determine whether ceramide formation can be regulated. Bovine cumulus-oocyt...
Article
Programmed cell death through the sphingomyelin pathway has been suggested to underlie the mechanism by which heat shock disturbs oocyte developmental competence. Serial experiments were performed to characterize the role of the sphingolipid ceramide in heat-shock-induced apoptosis, and to determine whether ceramide formation could be regulated. In...

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Projects (2)