جستجوی مقالات مرتبط با کلیدواژه "milk production" در نشریات گروه "دامپزشکی"

Mastitis, which is caused by inflammation of the mammary gland, is the most common and costly disease that affects dairy cows around the world. Treatment of mastitis during lactation is not recommended due to the risks of milk contamination with antibiotics in lactating cows. In this research, (Pulegium Mentha) plant was used to treat subclinical mastitis in Holstein cows. For this purpose, 50 Holstein cows with subclinical mastitis with an average age of 4.5 years and in the middle of the lactation stage with an average production of 20±2.7 were selected. The research was conducted in the form of a completely randomized design with two treatments and twenty-five repetitions, which treatments were: 1- control (no injection of Oji essential oil into the breast area) 2- injection of Oji essential oil into the breast area. The results of the present study showed that the injection of Oji essential oil into the mammary gland improved the average amount of milk production, reduced somatic cells, and increased the percentage of protein, fat and lactose in cows' milk (P<0.05). However, there was no significant difference between the Oji treatment and the control in terms of total elimination of intramammary infections. In general, the results of the study showed that Oji essential oil can be used in the treatment of subclinical mastitis in cows.

The aim of this study was to investigate the effect of saturated and unsaturated fat sources in the diet of late pregnancy and early lactation on histological changes in the mammary gland of nulliparous Saanen goats. Thirty does from the second half of pregnancy were divided into three groups based on body weight. For each group, the diet contained either: 1) saturated fat (positive control, C+), 2) roasted soybeans (omega-6, SB), or 3) extruded flaxseeds (omega-3, FS). Milk production was determined weekly and mammary tissue sampling was performed three times after kidding and the histological information of the mammary tissue was obtained using Image J software. The results showed that consumption of flaxseed and soybean increased milk production in the whole period compared to the C+ group (P<0.05).  The percentages of epithelial cells and stroma were the highest and the lowest, respectively in the FS group compared to the other groups(P<0.05). The areas of alveoli, lumen, epithelium and the number of epithelial cells per alveolus were higher in the SB group; however, the number of alveoli per unit area  was lower in SB group than  in the other groups (P<0.05). Based on the results, it is concluded that the consumption of diets rich in unsaturated fatty acids, especially omega-3 fatty acids, in critical periods of mammary gland growth, affects growth and development of mammary tissue, improves lactation performance and increases milk production.

In order to investigate the effect of flaxseed consumption as a source of omega-3 fatty acids on the expression of genes effective in mammary gland tissue development in primiparous Sanan goats, 30 does (young female goats) in the second half of their first pregnancy were selected and divided into three groups of 10 based on their average initial live weight . One group received a diet without any fat source (negative control), the second group received a diet containing palm saturated fat (positive control) and the third group received extruded flaxseed (flax) as a source of omega-3. The diets of all three groups were adjusted according to the requirements of NRC 2007 dairy goats. Experimental groups received nutritional treatments from the last 2 months of pregnancy up to  4 months after parturition. During the experimental period, milk production was recorded weekly for each animal and mammary gland tissue sampling was performed three times, 24 to 36 hours after parturition, two and four months after parturition were performed to investigation the expression of IGF- 1, IGFBP3 and IGFBP5 genes. The results of this study showed that there was no significant difference among the treatments in terms of expression of the studied genes. Also, the interaction between treatment and time was not significant for any of the above genes and only the effect of time was significant for IGFBP-3 gene (P <0.05).

The aim of this study was to evaluate the effect of heat stress on milk production traits in Iranian Holsteins and estimate the genetic parameters of milk production trait under heat stress condition. To evaluate the effect of heat stress on the studied trait, the data set was included 587745 first lactation test day records of 70468 Holstein cows from 645 milk-recorded herds by the Animal Breeding Center of Iran. The weather information was obtained from a meteorological organization. The temperature humidity index (THI) in recorded days was calculated and used in the model.   Effect of impressive factors on milk production including herd, year, season of calving milking times, the month recording, and temperature humidity index was the investigated by GLM process in SAS software and significant effects included in analysis model. Random regression model carried out to estimate genetic parameters under heat stress conditions using BlupF90 software. The results of fixed effects analysis showed that all survived factors had a significant effect on the milk production trait. The threshold point for THI was 72, and then by increasing THI up from 72, milk production decrease. This reduction is   -0.056 for increasing each unit in THI. The range of heritability for milk production trait estimated 0.1 - 0.22 and the correlation between THI and milk production was in the range 0.1- 0.9. The highest heritability related to the period that animal was in end of lactation and the THI was the lowest.

Urea is a non-proteinaceous nitrogen source, often used as a substitute for raw ration protein in order to reduce the feeding cost of livestock.

The purpose of this study was to investigate the effects of substitution of different levels of slow-release urea with soybean  meal on feed intake, milk production and composition, and blood parameters of lactating cows in early lactation.

Twelve Holstein cows were selected at the third birthday, milk production of more than 30 kg per day, and from 10 to 100 days after birth, with four diets, the treatments included 0, 23, 0.46 and 0.69  % of slow-release urea was replaced by soybean meal. Feed intake was measured daily. The milk sample was taken on the day of the start of the experiment and was taken at intervals of 14 days. To measure glucose, urea, cholesterol, triglycerides, high density lipoprotein, and low blood levels, were determined  from the start of the test to the end of the test every two weeks.

Consumption of feed, milk production and composition did not differ from experimental treatments. Glucose concentration and blood parameters (cholesterol, high and low density lipoprotein) did not differ between experimental treatments, but triglyceride and lipoprotein showed a very low density at zero (P <0.05).

The results of this study showed that adding slow-release urea to the level of 0.69% had no negative effect on feed consumption, milk production and composition, and blood parameters.

Urea is a non-proteinaceous nitrogen source, often used as a substitute for raw ration protein in order to reduce the feeding cost of livestock.

The purpose of this study was to investigate the effects of substitution of different levels of slow-release urea with soybean  meal on feed intake, milk production and composition, and blood parameters of lactating cows in early lactation.

Twelve Holstein cows were selected at the third birthday, milk production of more than 30 kg per day, and from 10 to 100 days after birth, with four diets, the treatments included 0, 23, 0.46 and 0.69  % of slow-release urea was replaced by soybean meal. Feed intake was measured daily. The milk sample was taken on the day of the start of the experiment and was taken at intervals of 14 days. To measure glucose, urea, cholesterol, triglycerides, high density lipoprotein, and low blood levels, were determined  from the start of the test to the end of the test every two weeks.

Consumption of feed, milk production and composition did not differ from experimental treatments. Glucose concentration and blood parameters (cholesterol, high and low density lipoprotein) did not differ between experimental treatments, but triglyceride and lipoprotein showed a very low density at zero (P <0.05).

The results of this study showed that adding slow-release urea to the level of 0.69% had no negative effect on feed consumption, milk production and composition, and blood parameters.

Milk production traits and its components belong to quantitative and polygenic traits and affected by many genes. This study was conducted to determine the polymorphism in alpha-lactalbumin gene and its association with milk production traits using PCR-SSCP method in Eastern Azarbaijan native buffaloes. Milk samples were collected from 150 buffaloes of Eastern Azarbaijan province and then DNA samples were extracted using pronase method. After DNA extraction specific primers used for amplification of 392 bp fragment of exon 1 and intron 2 alpha-lactalbumin gene. To identify the polymorphism, PCR products were electrophoresed on polyacrylamide gel (single strand conformation polymorphism method) and stained with silver nitrate method. The frequency of the 1, 2 and 3 genotypic patterns were 87.5%, 10.71% and 1.78% respectively. The statistical analysis indicated that the effect of genotypes on milk production, lactose, fat percentage and protein percentage had no significant effect. Based on current results, the analysis of alpha-lactalbumin gene polymorphism cannot be used for improving milk yield and composition of buffalo in Azari population.

The infection in dairy heifers may damage the developing secretary tissues reducing the future milk production in such animals. The efficacy of antibiotics for treating MI in unbred and primigravid heifers has been demonstrated by a few researchers. The objective of the present study was to compare the times of dry cow therapy in control of post partum MI and milk production in primigravid heifers. For this porpose, 75 primigravid heifers were selected and placed in three groups including: 60 day before parturition (group A), 30 day before parturition (group B), and 30-60 day before parturition (group c). Perepartum mammary glands secretion were collected to investigate microbial contamination.Then, intra mammary treatment with cloxacillin ointment was done in 50 heifers in two groups of A and B. In 3th day after parturition, 10 ml milk sample of 75 heifers was collected separately in 12ml sterile tube to investigate microbial contamination. Milk producing of heifers in three groups was recorded in 30, 60 and 90 day after parturition. Based on bacterial culture results mammary gland secretaries, in before and after parturition, the least bacterial contamination was observed in group B heifers and the most contamination was observed in control group of heifers. Between Heifers in group A and C, significant difference were found. By survey on milk production of three group heifers, it was found that there is significant differentiation between milk production in 30 and 90 day after parturition in three group and maximum production was demonstrated in group B and then in heifers group A. In this research, the best response to the treatment was demonstrated in group B, but, because of probability of antibiotic persistence in milk, recommended that dry cow therapy be done in 60 day before parturition.

To evaluate the effects of physically processed flaxseed [ground flaxseed (GFS) and whole flaxseed (WFS)] as a replacement for extruded soybeans on feed intake, milk production, milk composition, milk fatty acid (FA) composition and blood biochemical parameters, nine primiparus Holstein dairy lactating cows averaging 495 ± 34.5 kg of body weight (BW) and 70 ± 5 days in milk (DIM) were assigned in a 3 × 3 change over Latin square design with three periods. Intake of dry matter was similar among the animals fed the treatments, also milk yield and milk composition were not influenced by the diets. Processing of flaxseed significantly (P<0.05) affected plasma glucose and urea concentrations. Feeding ground compared with whole flaxseed and extruded soybeans, caused a significant (P<0.05) increase in the concentration of total long-chain fatty acids in milk, also α-linolenic acid (18:3) content nearly doubled with GFS compared with those of the other treatments (0.75 vs. 0.36 and 0.46 g/kg milk production for GFS, ESB or WFS, respectively). Linoleic acid (18:2), content of milk was also significantly (P<0.05) increased by inclusion of the ground flaxseed compared with the other treatments. In general, feeding ground flaxseed had a significant (P<0.05) effect on monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) concentrations compared with those of the cows fed extruded soybeans or whole flaxseed.