جستجوی مقالات مرتبط با کلیدواژه « عملکرد تولیدمثلی » در نشریات گروه « علوم دام »

Estrus synchronization is a valuable management tool that has been employed in enhancing reproductive efficiency in ewes. Synchronization of estrus and ovulation for fixed-time artificial insemination in sheep is mostly based on the insertion of intravaginal devices containing either progesterone CIDR (Controlled Internal Drug Release) inserts or progestagens (sponges impregnated with fluorogestone acetate (FGA) or medroxyprogesterone acetate (MAP)). Intravaginal sponges are usually inserted over periods of 12 to 14 day and used together with eCG, particularly out of season, administered at the time of sponge withdrawal or 48 hours prior to sponge removal. It has now been indicated that shortening the duration of progesterone treatment with intravaginal instruments, while being effective in inducing estrus and ovulation, reduces the incidence of vaginal infections and consequently improves fertility. On the other hands, it has been reported that pregnancy rates of progestagen-synchronized ewes were lower during anestrus than during the breeding season. Therefore, this study was conducted to investigate the reproductive performance of indigenous ewes in Khanmirza city with short-term and long-term estrous synchronization programs accompanied by eCG during breeding and anestrous season. Moreover, efficacy of estradiol injection instead of gonadotropin during short-term progesterone treatment was evaluated in both seasons. The experiment was performed at two periods, during the breeding and the anestrus seasons on 2 different groups of 400 ewes. During each season, ewes (2 to 5 years of age and average body weight of 45±2.5 kg) were allocated to 4 groups of 100, in the way that each experimental group contained an equal number of ewes of a particular age. Experimental groups were: Control (without any synchronization program), Short term-estradiol group (ewes received 12 days progesterone treatment and intramuscular injection of 1mg estradiol benzoate at the time of sponge removal), Short term-eCG group (ewes received 12 days progesterone treatment and intramuscular injection of 400 IU eCG at the time of sponge removal) and Long term-eCG group (ewes received 14 days progesterone treatment and intramuscular injection of 400 IU eCG at the time of sponge removal). The progesterone treatment consisted on a vaginal sponge which contained 60 mg Medroxyprogesterone Acetate. Then, the ewes were placed in pens and one healthy ram was introduced for every 5 ewes, in order to detect heat and mating. Estrus signs were detected and recorded every hour for 5 days. The percentages of ewes that showed overt signs of estrus during a period of five days (estrus rate), estrus onset (the time elapsed between sponge removal and the first accepted mating) and pregnancy rate (The number of ewes without showing signs of estrous after 42 days of mating/total number of ewes×100) were recorded. Fecundity and prolificacy rate was calculated based on the number of lambs born. Lambs were monitored for 30 days after birth and deaths among them during this period were recorded against the ewes which were their mothers, and the survival rate was determined. The multiple birth rate was calculated by combining the twin and triplet birth rates. The results showed that reducing the duration of treatment with progesterone sponge in both trial period (autumn and spring) led to a significant reduction in estrus rate (P ≤ 0.05), but had no significant effect on other reproductive parameters (P > 0.05). Regardless of the season, injection of estradiol instead of eCG on sponge removal day, while increasing the estrus rate of ewes, led to a sharp increase in the rate of return to estrus (P ≤ 0.05) and caused decreases in the percentage of pregnant ewes, percentage of parturition ewes and lambing rate (P ≥ 0.05). In the breeding season, the mortality rate of lambs born from progesterone-synchronized ewes decreased and fecundity increased numerically compared to the corresponding group in breeding season group. Lack of possible effect of the anestrus season during synchronization programs on estrous rate and fertility of ewes can be attributed to optimal nutritional conditions of ewes in this season. Short term progesterone treatment (12 day) as well as injection of estradiol benzoate instead of eCG is not recommended to synchronize the estrous of ewes during both reproductive and anestrus seasons. In other words, short-term progesterone treatment (12 days) was not effective to synchronize estrus in breeding and anestrous sheep which can be attributed to follicular dynamics.

The profitability of dairy cattle herds mainly depends on the reproductive performance of cows. Because reproductive performance is effective on the amount of daily milk and calf production per cow, increasing the number of inseminations per conception, lengthening the calving interval in the herd, and causing the voluntary (due to the age of the animal) and involuntary (due to illness or fertility disorders) elimination. For evaluating fertility traits, we sometimes come across domains whose records were incomplete at the time, out of range, or delayed. These records are called censored records. The typical way to deal with such records is to delete them from the data set. However, this reduces the information available for genetic evaluation and may affect trait variance by masking actual genetic differences between animals. Another way is to use appropriate statistical methods to place censored records in genetic evaluations. The use of censored records in genetic evaluations yields more reliable genetic parameters, and it can increase the estimation accuracy of breeding values giving the support that the breeding value estimation is close to the true breeding value. The present study aimed to investigate the role of censored records in the estimation of genetic parameters of the number of inseminations per conception in Iranian dairy cows.
The dataset included 29621 records collected from 2005 to 2019 by the Vahdat Cooperative of Isfahan in Iran. FoxPro software (version 9.0) was used to edit and prepare data, remove incorrect records and create contemporary groups. Five animal models, including Threshold Model (TM), Penalty Model (PM), Modified Penalty Model (MPM), Threshold-Threshold Model (TTM), and Modified Threshold-Threshold Model (MTTM), were used for the genetic evaluation of this trait. The predictive ability of the models was assessed using cross-validation. Also, a simulation study was performed to determine the appropriate model.
The estimated heritability using different models was 0.3 (0.013), 0.07 (0.013), 0.07 (0.013), 0.3 (0.13), and 0.4 (0.012) for TM, PM, TTM, MPM, and MTTM, respectively. The highest correlation of breeding values for all animals was between MPM and TM (0.98). The same result was obtained for the best sire (sire with at least 20 daughters). The high correlation shows that these models work similarly in selecting the best sires. The low correlation between models indicates that the models rank sires differently. Therefore, the choice of model can affect the ranking of males. The top 10 sires showed less correlation between models than the active sires. When the number of males decreases, the selection becomes more strict. The prediction accuracy in models with censored records is higher than in models without censored records because the use of models that include censored records is due to the increased information about the trait, and the absence of bias due to deleting records improves the accuracy of estimating breeding values. Consequently, if the censoring status is not taken into account, animals with superior breeding values may be biased. The low ratio of common superior animals in different percentages between models showed that these two models rank the animals differently. Still, the high proportion of common superior animals indicates the similarity of the two models in choosing the best animals. So, model selection can be effective in ranking superior animals because when the censored record is used, the information is increased and the situation would be closer to reality. The cross-validation showed that the accuracy of the breeding value prediction by different models was higher in models with censored records than in models without censored records. The results of the simulation study showed that the models with censored records provided better genetic parameter estimates. TTM has been able to estimate expected heritability better than other models. The percentage of top animals in common between the top 10 and the top one percent of simulated animals with different models showed that the ability of the TTM model to select real top animals is more than other models, which shows that this model has identified top animals better.
The results of the present study showed that the censored records are important for estimating the genetic parameters of the number of inseminations per conception in Iranian dairy cows and ignoring those led to a biased estimation of the parameters. Data simulations also showed that using censored records provided more realistic genetic parameter estimates.

 Nowadays, endotoxemia is considered as one of the fundamental causes of infertility in different animals or humans due to various bacterial infections because of the entry of lipopolysaccharide (LPS) in the membrane of the gram-negative bacteria’s wall into the blood. This study aimed to evaluate the inflammation caused by LPS and the protective effect of kaempferol (KAE), which is a natural flavonoid with anti-inflammatory and antioxidant properties on oocytes developmental competence.

For this purpose in oocyte maturation medium, in the first experiment with concentrations of 0, 0.1, 0.1, 1 and 10μg/ml of  LPS, in the second experiment with concentrations of 0, 0.1, 1 and 10 μM of  KAE and in the third experiment with concentrations of  0, 0.1, 1 and 10 μM of  KAE  with  LPS  were cultured for  24  hours. After in vitro maturation, mature oocytes were identified and fertilized with incubated sperm, and the rates of cleaved oocyte and oocytes reached to blastocyst stage were analyzed.

The treatment with 1 and 10 μg/ml of LPS significantly reduced blastocyst rate compared to the control group (p<0.05), but supplementation of oocyte maturation medium with different concentrations of KAE had no effect on the rates of cleaved oocyte and oocytes reached to blastocyst stage (p>0.05). In addition, the results of different concentrations of KAE with LPS show that KAE  did  not has no significant effect on the rates of cleaved and blastocyst oocyte inflammatory conditions caused by lipopolysaccharide (p>0.05).

In summary, the data presented here have shown that LPS exhibits detrimental effects on sheep oocyte development in a dose-dependent manner and KAE is not effective in ameliorating these effects.

The present study aimed to determine the proper weaning age of Zel lambs. For this purpose, ninety male and female lambs (average live body weight =2.57±0.41 kg) selected and were divided into three groups (each group = 30). The experimental treatments were; 1. weaning at an average age of 60 days, 2. 75 days, or 3. 90 days. The lambs were introduced to fattening program and were fed with iso-energetics and iso-nitrogenous diets until 6 months of age. The dam’s ewe of all groups enters to mating program two months after parturition and ewe lambing data contain dam’s weight, lamb’s mortality, litter size, lamb’s birth weight, and sex were recorded. Results showed that dry matter intake (DMI) and feed conversion ratio (FCR) did not affect by weaning age of lambs. The lambs that weaned at 60 days old, had higher average daily gain (ADG) at fattening period, then lambs were weaned at 75 and 90 days old, significantly. The parturition rate, prolificacy rate, lambing rate, and litter size of groups weaned at 60, 75, and 90 days of age were 88, 81, and 85; 119, 118, and 117; 104, 96, and 100; and 19, 18, and 17% respectively, and did not observed significant between the treatments. It concluded that Zel lambs weaned at 60 days old, could increase growth performance compared to elder lambs, and improves the reproductive performance of ewe.

The aim of this study was the comparison of two protocols of estrus synchronization in two natural climates and heat stress condition on reproductive performance and concentration of plasma estrogen and progesterone hormones in Holstein dairy cows. One hundred and ten multiparous Holstein dairy cows (28 kg average daily milk yield and parity one to four calved) were randomly assigned to two protocolgroups: 1) Double-Ovsynch (DO; n=60), the cows received GnRH-7d-PGF2α-2d-GnRH and Ovsynch (GnRH-7d- PGF2α-56h-GnRH-16h- AI) was initiated 7 d later; 2) Presynch-Ovsynch (PO; n=50), the cows received PGF2α-14d-PGF2α and Ovsynch was initiated 12 d later. The both of the protocols were done in two seasons of summer and winter. The calving rate in cows that were synchronized at winter season was greater than cows synchronized in summer (36.4 vs 18.2%; P= 0.04). Mean of the number of insemination to conception was lower in cows that synchronized in winter compared to cows synchronized in summer (1.46 vs 1.74; P= 0.02). Mean of measured estrogen and progesterone hormones concentrations was higher in cows that synchronized in winter compared to summer (P < 0.05). Overall, mean of reproductive traits and hormones concentration is higher in cows that synchronized in winter than in summer and the protocol of estrus synchronization had no effect on reproductive performance.

Nutritional and hormonal programs are one of the important ways of improving goat reproductive performance. Therefore, the present study was conducted to investigate the effect of using barley seed and eCG at the same time on the reproductive performance of goat in nomadic breeding conditions. The number of 60 goats of two to three-year-old in the breeding season and 60 goats of three to four-year-old in out-breeding season were chosen. Then the goats were divided into six groups of 10 numbers. 1- Control group (without receiving barley seed and eCG); 2- Group receiving 400 grams of barley for eight days (short term); 3- Group receiving 400 grams of barley for 16 days (long term); 4- Group receiving 400 IU eCG; 5- Group receiving 400 IU eCG and 400 grams of barley for eight days and 6- Group receiving 400 IU eCG and 400 grams of barley for 16 days. The results indicated that in-breeding season twinning rate in groups receiving barley for short and long term with eCG were higher compared to the group without receiving eCG. At the same time, the minimum (five) and maximum (20) numbers of  born kids were observed in control and group six, respectively. The results also indicated that in out-breeding season none of the characteristics were influenced statistically by treatments. It can be concluded that using 400 IU of eCG and 400 grams of barley seed daily, can improve the twinning rate in breeding season but such an effect cannot be observed in out breeding season.

The effects of different levels of fish oil on productive and reproductive performance as well as serum biochemical indices in female Chukar partridges were evaluated. Thirty-six 1.5-year-old laying Chukar partridges and 12 age-matched males (female: male ratio of 3:1) were divided to four experimental groups (three replicates of three birds each) in a completely randomized, to orally receive 0 (control), 0.1, 0.2, or 0.3 mL of fish oil on a daily basis for 21 successive days where the control birds received 0.3 mL normal saline solution only as the sham control group. The birds had a free access to feed and fresh water and were weighed weekly. The eggs (n=271) were collected once per two hours during the photophase (8 times daily) for the last 21 days of the treatment period (from 7 through 28 d of experiment). Blood samples were collected on d 0, 10, and 21 of the trial to analyze selected biochemical attributes. Although administration of 0.2 mL fish oil increased the egg production and fertility rate, the difference was not significant as compared to the control group (p> 0.05). Feed intake, body weight, and daily weight gain were not influenced by the different levels of fish oil. A significant decrease in egg weight was detected in fish oil-fed birds where partridges receiving 0.2 mL fish oil recorded the lowest egg weight among the experimental groups (p< 0.05). Similarly, the birds administered with different levels of fish oil had lower serum total cholesterol and triglyceride levels compared to the control group where the lowest records were found for 0.3 mL fish oil level. The interaction effect of fish oil level and time on serum total cholesterol was significant (p=0.02). The serum levels of LDL and glucose were decreased in partridges receiving 0.3 mL fish oil (p<0.05). No significant changes in the serum concentration of VLDL, HDL, total protein, calcium, and phosphorus were found during the trial. Data suggested that oral exposure of Chukar partridge to 0.2 mL of fish oil had poitive effect on egg production and fertility rate. However, egg weight was decreased. Oral administration of 0.3 mL of fish oil may decrease serum total cholesterol, triglyceride, LDL, and glucose in partridges.

This study was conducted to evaluate the effect of various concentrations of lipopolysaccharide (LPS) in maritaruta medium on oocyte maturation, oocyte developmental competence and metabolites related to maturation medium including glucose, pyruvate, lactate and glutamine. The experimental treatments were 0 (control), 0.01, 0.1, 1 and 10 μg/ml of LPS in oocyte maturation medium. The cumulus oocytes complex (COC) were cultured with various concentrations of lipopolysaccharide. After 24 h of oocyte maturation, the medium was collected and the rates of oocyte maturation, cleaved oocyte and oocytes reached to blastocyst stage were analyzed. Oocyte maturation rate was lowest in the treatment with 10 μg/ml of LPS (P<0.05). Among the measured metabolites, only glucose concentration was linearly decreased in response to increasing levels of LPS in the maturation medium (P<0.05) as treatment with 10 μg/ml of LPS had lower glucose concentration comparing to other treatments. The percentage of oocyte cleavage was significantly lower in treatment with highest level of LPS compared to other treatments (P<0.05). In addition, the treatment with 1 and 10 μg/ml of LPS significantly reduced blastocyst rate compared to control group (P<0.05). According to results of this study, lipopolysaccharide could have detrimental effects on oocyte development and these influences seems to be mediated through pathways related to energy metabolism. Acquiring managerial approaches to control LPS enhancing agents during reproductive season could prevent animal's reproductive failure.

During the past decade, genetic selection for milk production has been very progressive in dairy cows. The postpartum stage in dairy cattle is one of the most important stages in the performance of dairy cattle. Providing food nutritious with feed processing at this time interval can be effective in meeting the needs of the livestock. Recent experience suggests that the use of processed grains instead of milled grains can greatly improve the production and reproductive conditions in dairy cattle. Therefore, the purpose of this study was to compare the production and reproductive performance of freshly-produced dairy cows in two modes of steam flaked-and-grained cereal grains.

This experiment was conducted in a completely randomized block design in a 100-day period in which 40 dairy cows were reared in 4 treatments: Milled barley and corn, corn steam flaked and milled barley, barley steam flaked and corn and barley stream flaked. Throughout the experiment, cows were housed in the straw yard. Treatment diets were: 1) Control diet (milled grains), 2): steam flacked corn with milled barley (SCGB) 3): steam flacked barley with milled corn (GCSB), 4): steam flacked corn and barley (SCSB). Diets were arranged in CNCPS software based on NRC requirements for dairy cattle. Productive performance (milk, fat, protein), feed consumption behavior, and reproductive performance were evaluated among the four groups. All statistical analyzes were performed in SAS software version 9.1.

The results showed that the use of steam flaked barley and corn in ration increased the production efficiency in fresh cows (P <0.05), So that the simultaneous use of stream flaked corn and barley compared to the milled, increased the amount of cumulative milk from 3196 to 3731 kg, but the percentage of lipid and milk protein was not affected by experimental treatments. Pregnancy rates and open days in barley and corn treated with steam flaked were improved by 13% and 11 days, respectively (P<0.05). The chewing rates were higher in stream flaked corn and barley compared to the milled (64 times in treatment 4 to 58 times in treatment 1), which had a significant difference.

The use of steam flaked corn and barley improves reproductive, reproductive performance and improve production performance in freshly dairy cows instead of barley and corn milled also reduces open days, calving interval and increase conception rate, pregnancy rate in first 100 days and total pregnancy rate ,which can lead to economically important.

Reproductive performance is the most important economic trait in sheep production and it can be manipulated by using hormonal treatments. Equine chorionic gonadotropin (eCG) is widely used for improving the fertility in ewes. In some studies the use of low and high doses of this hormone increased number and the size of large follicles and also it could enhance the ovulation rate, but it decreased pregnancy rate. As it was not found any report about the effect of using eCG on reproductive performance of Torki-Ghashghaei ewes, this study was conducted to investigate the effect of different dose of eCG on estrus response, estrus onset, pregnancy rate and twining rate of these ewes in autumn season.
In this study, the total of 75 cyclic ewes with the mean weight of 573.6 kgs were randomly assigned to five experimental groups (n=15/group). The estrous cycle of all ewes was synchronized with the insertion of intravaginal progesterone sponges during a 12 days period. One day before withdrawaling progesterone sponges 300, 400, 500 and 600 IU eCG were injected intramuscularly to ewes in group Π, Ш, ΙV and V, respectively and the group Ι (without eCG injection) was used as control group. The reproductive variables such as: time of estrus onset (hour), estrous response, pregnancy rate, twining rate, fecundity and prolificacy rate were measured in this experiment.
Estrous responses for all eCG recipient ewes (100%) were significantly higher (P Generally, the results showed that injecting 600 IU eCG had the most effect on increasing pregnancy rate and twining rate in Torki-Ghashghaei ewes in autumn season.

The aim of this current study was using of a management and feeding program in order to improving of reproductive factors performance in one hundred head ewes with Iran Black bred. Ewes were placed in two A (75 head) and B (25 head) groups. Ewes of A group were milk-cutted and were introduced to rams 80 and 90 days after parturition respectively. Forty days before introduction to rams, melatonin implant was laid under skins of these ewes. 75 ewes of A group were kept separately in three groups of 25th and were fed by high starch diets complemented with saturated fatty (control treatment), extrude cotton seed (omega 3 treatment) and full fat soybean (omega 6 treatment). B group’s ewes were milk-cutted and introduced to rams 120 and 180 days after parturition and were fed the same as control treatment diet. Estrus, ovulation, lambing and twining rates were counted and recorded in various experimental treatment. The weight of lambs were measured in time of birth, 3th and 4th month. Lambing and twining rates was higher in omega 3 and omega 6 treatment than control treatment and B group. Lamb weight average in their 3 and 4 month old was significant higher in B group than all treatment of A group. Generally, results of this study showed that using of management program of A group along with omega 3 and 6 feeding could improve reproductive factor performance.

Estrus synchronization is a valuable technique in control of reproductive function in ewe. The aim of this study was to determine the status of estrus incidence and hormone profiles in blood serum of Arabic ewes synchronized using the long and short periods of CIDR in non-breeding season. In non-breeding season, a total of 58 Arabic ewes aged 2-5 years old (average of BW 46 kg) and non pregnant in a completely randomized design were assigned to three experimental groups: 1- control (no treatment), 2- short-term (6 days) and 3- long-term (14 days) treatments with vaginal CIDR. Immediately after removing the CIDR, 600 IU of PMSG was injected intra muscle. In the CIDR treatments, estrogen and progesterone concentrations of blood serum were measured immediately before of CIDR insertion, three days after CIDR insertion, one day after CIDR removal and 50 days after mating. In order to heat detection and mating, one healthy and fertile Arabic ram was introduced to every 5 ewes. The interval to estrus after CIDR removal in short and long term treatments, were 51.02 and 34.74 hours, respectively (P<0.01). Occurrence of estrus in short-term (88.8%) and long term (95.2%) treatments of CIDR was higher than control (5.26%) (P<0.01), but this difference between CIDR treatments was not significant (P> 0.05). One day after CIDR removal and 50 days after mating, estrogen concentration of blood serum was significantly higher in long-term than the short-term CIDR treatment (P<0.01). There was no significant difference in blood serum progesterone level between treatments in all times (P>0.05). The concentrations of these hormones in various periods of short and long term treatments of CIDR were in fluctuant. The use of short term (6 days) CIDR has the appropriate estrus occurrence and reproductive function in non breeding season of Arabic ewes.

A number of 52 Arabian ewes with 2-5 years old were randomly divided to three groups: 1) insertion of CIDR for 6 days (n=18), 2) insertion of MAP sponge for 6 days (n=15) and 3) control group without treatment (n=19). In hormonal treatment groups, 600 IU eCG was injected intra muscularly at the time of withdrawal of the above devices. Then, one fertile and health Arabian ram introduced to each five ewes in order to standing heat detection and mating. Estrous response rate, estrous onset time, repeat breeding, fertility, lambing rate, gestation length, litter size, lamb weight and blood serum progesterone values in experimental treatments were studied. Estrous response in CIDR and sponge groups were significantly higher than the control group (P<0.05). Estrous response was not differ between hormonal treatments (P>0.05). There were not significant differences for mean time of estrous onset after withdrawal of progesterone devices, repeat breeding rate, fertility rate, lambing rate, pregnancy duration, litter size, lamb weight and blood serum progesterone concentrations at before and 3 days after insertion of these hormonal devices as well as 50 days after mating between short term CIDR and sponge treatments (P>0.05). One day after removing the CIDR and sponge devices, blood serum progesterone level in CIDR treatment was significantly higher than that in sponge group (P<0.05). The highest estrus responses in short term CIDR and sponge treatments were observed in 36-48 and 48-60 hours after removal of these devices, respectively.

This study was conducted to evaluate the effects of extruded linseed on milk production, dry matter intake and reproduction performance of 300 Holstein lactating cows (35±15 days in milk; 41±9/8 Kg/day of milk production). Cows were utilized in a completely randomized experimental design, comprised of: 2 treatments (concentrate containing 7 percent extruded linseed vs control) with a number of 150 cows per treatment. Cows were fed a balanced total mixed ration (610 g concentrate /kg DM and 390 g forage /kg DM) 3 times daily, and milked 3 times daily. Cows in group 1 were fed TMR without extruded linseed (control); cows in group 2 were fed totally mixed ration with TMR with containing extruded linseed (7 percent of concentrate). Extruded linseed did not affect milk production and dry matter intake (P>0.05). Treatment of feeding cows with extruded linseed caused them to have higher Pregnancy rates, lower number of open days, and fewer number of inseminations (P<0.05). It was concluded that extruded linseed can increase reproduction performance of Holstein dairy cows in their early stages of lactation

Thirty-six Moghani ewes with a history of two parities, weighing 55±5 kg were allocated in 3 groups (n=12) to investigate the impact of flaxseed and soybeans grains in the complementary randomized design on the ewes metabolites and hormones in blood, and their reproductive performance through a period of the 35 days. The experimental treatments were: 1- Flaxseed (F) (5% of total ration dry matter), 2-Soybean (S) (5% of total ration dry matter) and 3- Control (C) (without seed oil) respectively. Isonitrogenous (9% CP) and isocaloric (3.6 Mcal/kg) experimental diets were used. Body condition score of ewes at the beginning of experiment were 2.5 and reached to about 3 at the breeding time. Ewe's estrus was synchronized using CIDR 14 days before mating. 24 hours after CIDR removal, ewes were mated randomly with 5 rams of the station in the first of June. The usage of oilseeds improved fertility and lambing rate (P<0.05). Glucose, cholesterol, insulin and estrogen hormones levels of serum were higher in experimental diets containing flaxseed and soybean seeds than the control group (P<0.01).

To evaluate the effects of different dry period lengths on milk yield, milk composition, reproductive performance and energy balance in dairy cows, 30 Holstein breeds (average 270 days pregnant) were made use of in a randomized complete block design. Cows were assigned to three treatments (60, 45 and 30 days of dry period) and two blocks as based on parity (either first lactation or multifarious cows). Milk production and composition as well as somatic cell counts of cows with 45 and 30 days of dry period were not significantly different from cows with 60 days of dry period (P>0.05). Body condition score changes after calving for 60, 45 and 30 days of dry period (1.06, 0.93 and 0.68, respectively) were significantly different. The smallest change in body condition score was observed for 30-day dry period ones, which also had a lower blood concentration of non-esterified fatty acids before calving (364.8 vs 394.9 and 390.9 µEq/l for 45- and 60-day dry periods). Mean days to first postpartum ovulation were 27.9, 27.8 and 22.7 days for dry periods of 60, 45 and 30 days, respectively (P<0.05). Fewer numbers of services per conception was recorded for 30- day dry periods compared with 45- and 60- day dry periods (1.5 vs 2.1 and 3.75, respectively). Cows with 30-day dry periods as experienced fewer number of days in negative energy state in comparison with 60- and 45-day dry periods, which amounts to a better reproductive performance.

This experiment was conducted to evaluate the effect of various supplemental fats applied in the flushing diet on reproductive performance, blood metabolites and hormones of Ghezel breed ewes. 36 Ghezel sheep were assigned in three treatments for 42 days in completely randomized design. Experimental groups were as follow: control (without supplemental fat in diet), sunflower oil (5% of ration dry matter) and calcium salts of palm oil (5% of ration dry matter). Experimental rations had the same Metabolisable Energy (3.6 Mcal/kg) and Crude Protein (9.2%) contents. CIDR was used for estrus synchronization. Insemination was done 48 hours after CIDR removal. Supplementation of fat resulted in higher levels of blood total serum cholesterol (P 0.01). Groups with Sunflower oil in flushing diet had higher blood glucose levels than others (P<0.01). Blood sera concentrations of insulin and estrogen were higher in sunflower oil supplemented group than others (P<0.05). Fat supplementation of flushing diets resulted in lambs with greater birth weight (P<0.05). The number of offspring and twining birth was higher in the sunflower oil treatment (P<0.01). Results indicated that, using sunflower oil in flushing diet increased metabolites and hormones related to reproduction and subsequently improved offspring number and twining.

To study calving interval and days open of Holstein cows in West and East Azerbaijan Provinces and the effects of some factors on them، 2213 records from ten herds collected during years 2000 to 2008 were used. The statistical analysis of data was done with proc. GLM (generalized linear models procedure) of SAS. The mean (±SE) of calving interval and days open were 395. 12±1. 36 and 115. 38±2. 98 days، respectively. Effects of herd، lactation number، year of calving and milk yield on calving interval were significant (P<0. 05). Effect of sex of calf on reproductive performance was not significant. Milk yield was increased from years 2000 to 2008. The relationship between milk yield and days open was not significant. It is important to give more emphasis on reproductive traits besides production traits to improve them in the herds of these two provinces.