مجله علوم دامی ایران
سال پنجاه و دوم شماره 4 (زمستان 1400)

Genetic selection for increasing milk production and economic profitability in the dairy industry has been associated with reduction in reproductive performance, including lower embryo survival and pregnancy loss. The main purpose of this study was to use the transcriptome profiles of endometrial tissue and Corpus luteum of two groups of high and low fertility Holstein dairy cows to identify genes that are effective in reproductive rate, especially in early pregnancy. By the analysis of RNA-Seq data to express the gene differences, 4538 genes were extracted, which a total of 1466 genes showed significant expression differences (P<0.000001, Fold change<0.5). Then, by comparing the relevant genes among transcriptome profiles, common genes between endometrial tissue (on days 7 and 13 of the estrous cycle) and Corpus luteum (on day 13 of the estrous cycle) including SYNM, PARM1, NXPE2, NT5DC3, COL4A3, COL12A1, ALPK3, ADAMDEC1, SERPINA14, S100A9, PI16, OAS1X, MSTN, MASP1, CD83, CA2, C2, C5, JSP.1 and SAA3 were identified. Annotation results of these genes indicated that they have a role in the main process of metabolic and signaling pathways related to the ion transport system, inflammation, immune system function, and cell-matrix structure. Overall, the present study can provide new insights into the molecular evidence for the biological mechanisms of transcriptome profiling in the uterine environment and biomarkers related to fertility in dairy cows.

The aim of this study was to compare the effect of rumen pH-adjusting additives on histomorphometry and histopathology of rumen, reticulum, liver, and kidney. Twelve Arabi male lambs, 9±1 months old and initial body weight of 35.95±3.55 kg were used in a completely randomized design with three treatments and four replicates in 35 days. The experimental treatments consisted of 1- A control diet, 2- Control diet+sodium bicarbonate buffer, 3- Control diet+Megasphaera elsdenii, and Saccharomyces cerevisiae (bacteria-yeast). At the end of the experiment, the lambs were slaughtered and tissue sampls from the liver, kidney, reticulum, and rumen were collected, and the tissue sections with thickness of 5 μm were prepared.  The wall thickness of the reticulum in the control treatment was significantly higher than the buffer recipient treatment (P<0.05). Also, the thickness of muscle-layer in the reticulum in the control treatment was more than other treatments and was significantly higher compare to the buffer recipient treatment (P<0.05). Papillae height and Papillae depth of reticulum in the bacteria-yeast recipient treatment were significantly higher than other treatments (P<0.05). In addition, the thickness of rumen epithelial tissue in the buffer and bacteria-yeast recipient treatments was less than the control treatment (P<0.05). The height of rumen papillae in the control treatment was significantly higher than the buffer and bacteria-yeast treatments. Infiltration of inflammatory cells into the liver, kidney and gastrointestinal tissues was observed.  In general, pH regulators, in high-concentrate diets protected the tissues, which were studied in the present experiment. In addition, the addition of bacteria-yeast effects as a biological regulator is comparable to the chemical buffer.

In order to investigate the effect of partial replacement of cereal grains with different levels of calcium saltd of palmitic and stearic saturated fatty acids on the performance of fattening lambs, 30 male Dalagh-Romanov lambs were used for 89 days. Experimental treatments included: 1- control diet (without fatty acid), 2- diet with 3 % palmitic acid  (PA), 3- diet with 3% stearic acid (SA), 4- diet with 3 %(67% PA+ 33% SA), 5- diet with 3 %(67% SA+ 33% PA). Growth performance (dry matter intake, average daily gain and feed convertion ratio), nutrient digestibility and blood parameters (glucose, blood urea nitrogen, cholesterol, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and liver enzymes) were measured. The results showed that experimental treatments had no significant effect on dry matter intake, feed conversion ratio and daily weight gain of lambs (P>0.05). Addition of fatty acid supplement to experimental diets significantly reduced dry matter digestibility (P<0.05). The concentration of high-density lipoprotein in diets containing fatty acid supplementation increased significantly (P<0.05). In conclusion, the results suggest that adding 3% )on the ration dry matter basis) PA and SA as alone or combine together in the diet for fattening lambs could be done without negative effects.

The aim of the present study was to detect Hepatozoon canis infection in dogs in Urmia municipality, northwestern Iran. The effects of age, sex, lifestyle, and tick infestation as risk factors in the incidence of the disease were studied. During years 2018 and 2019, a total of 246 whole blood samples were taken from the jugular vein of each examined dog (103 stray dogs, 99 shelter dogs, and 44 pets) and subjected to microscopic and molecular examinations. Ixodid ticks were also collected from the body surface and identified. Microscopically, infected neutrophils with Hepatozoon spp. were detected in 5 of 246 (2/03%) thin stained blood smears. Molecularly, 23 out of 246 (9.34%) blood samples were found to be infected with H. canis. There was no significant difference in different age groups and the sex of sampled dogs. However, stray dogs had a higher significant infection rate than pets and shelter ones. In body inspection, all ticks were belonging to the specie of Rhipicephalus sanguineus. The obtained sequence was transferred to GenBank/NCBI (samples accession numbers MT001887). BLAST analysis of obtaining sequences isolated from dogs indicated a 100% similarity with H. canis 18S rRNA gene sequences in GenBank. Based on our results canine hepatozoonosis was common in dogs in the study area.

Abortion in dairy cow can be categorized into two types of abortion: Rebreeding (RA, abortion incidence between 60 and 260 d of gestation, without change in lactation number), and new lactation abortion (NLA, abortion incidence after 200 d in gestation which leads to a new lactation). According to this definition, the losses of abortion might be different based on the type of abortion at the herd level. For this purpose, a partial budgeting model was developed to estimate the losses of abortion in 6 Holstein dairy herds located in Isfahan and Chaharmahal-Bakhtiari provinces during 2020. Financial losses due to reduction in productive and reproductive performances, replacement costs and calf loss were considered in this modeling. On average, loss of pregnancy was estimated 27.7 million IRR per case. Although the probability of NLA incidence was much lower than RA abortion (2.3% vs 12.5%), but NLA imposes significant financial losses to farmers (on average 32.4 million IRR vs. 22.0 million IRR per case). In general, decline in fertility was the most crucial factor of losses (63.3%) due to abortion, and decrease in milk yield (22.8%) placed in the second rank. The results obtained in this study can be used by farmers who make the optimal decision to keep or cull the aborted cows in the dairy farms.

The objective of this experiment was to determine the effects of fish meal supplementation on productive and reproduction performance in repeat breeder Holstein cows. Two hundred and sixty-one multiparous Holstein cows with at least three consecutive unsuccessful inseminations, without clinically detectable reproductive disorders, were randomly allocated to 1 of 3 dietary treatments. Dietary treatments were control, 2.5 or 5% fish meal, that replaced soybean meal. Cows were timed inseminated following the Double-Ovsynch protocol. Milk yield was (38.49, 39.92, and 41.42 kg/d, for cows fed the control, 2.5 and 5% FM diets respectively) of which the difference (P<0.01) between the control and 5% FM diets was significant. Likewise, 4% FCM was higher for treatment 5% FM relative to control (P<0.05). Milk fat, protein and lactose content (%) were not different among treatment (P>0.05) but milk protein yield was higher (P<0.05) for cows fed the 5% FM than control and 2.5% FM diets was significant. Plasma and milk urea nitrogen concentrations decreased significantly (P<0.05) affected fish meal by consumption. Plasma cholesterol concentration was higher for cows fed 5% FM compared to the control diet (P<0.01). Plasma progesterone concentration at 16 d post artificial insemination was greater for treatment 5% FM relative to control treatment (P<0.05). Pregnancy at the first service and cumulative (1st and 2nd service) for cows fed 5% FM content higher than control diet (P<0.05). These results indicated that supplementation the diet with 5% fish meal improved fertility and productive performance in repeat breeding cows.