مجله علوم دامی ایران
سال چهل و یکم شماره 1 (بهار 1389)

The objective of the present study was to estimate the lactation curve parameters through incomplete gamma function and to genetically evaluate the relationship of these parameters and udder traits in Holstein population of Iran. Two data set's including 117583 [(for lactation curve parameters) and 7351 (for determining genetic and phenotypic relationship between lactation curve parameters and udder type traits)], first lactation records on cows from 19303 and 1148 herd-year-season groups were respectively employed. Heritability estimates varied from 0.02 (a and b) to 0.22 (peak) and for udder type traits ranged from 0.11 (FU) to 0.21 (RTP).The genetic correlations among lactation curve parameters ranged from 0.99 (TTP and PERS) to -0.64 (a and b) and among udder type traits and lactation curve parameters ranged from 0.54 (RTP and a, RUW and PEAK) to -0.54 (RTP and b). Results suggested that the application of RUW for indirect selection of lactation curve parameters could be useful for genetic improvement of persistency in milk yield. With regard to the present study, cows with more udder width had a more M305, PEAK as well as PERS.

An experiment was conducted using 640 day-old sexed commercial broiler chicks (Ross 308 strain) from 10 to 49 days of age. The experimental design was a completely randomized factorial one. The experimental units (pens) contained 20 chicks each and were allotted at random to 4 dietary treatments × two sexes with 4 replicates per treatment. Four dietary treatments were formulated based on corn and soybean meal in mash form. All the diets were iso-protein and iso-energetic. The first dietary treatment was formulated without phytase, the second one containing 500 FTU/kg Natuphos phytase, and the third 500 FTU/kg Natuphos phytase (calculated equal to half of the nutrient equivalency values for Natuphos phyatse). The forth dietary treatment contained 500 FTU/kg Natuphos phyatse (calculated as the total nutrient equivalency values for phytase). Body weight gain, feed intake, and conversion ratio were assessed for grower (10-29 d), finisher (29-49 d), and the whole rearing period (10-49 d), separately. Also, carcass measurements, toe ash percentage, calcium and phosphorus concentration in toe ash, and blood phosphorus concentrations were evaluated at the end of the experiment. The results indicated that addition of phytase to diet significantly increased toe ash, and toe ash calcium as well as phosphorus content in male and female broiler chicks. The effect of sex was significant on body weight gain, feed intake, feed conversion ratio in grower, and in finisher period, toe ash percentage, Ca and P concentration as well as production number. Interaction between sex and dietary treatment was significant in terms of grower body weight gain, grower feed intake, as well as phosphorus content of toe ash. In summary, microbial phytase enhanced growth performance, and the calculation of nutrient equivalency values of phytase led to uniform performance in all dietary treatments, and as well as the reduction of production costs.

The objective of this study was to determine the effects of hulled and hull-less barley grains’ chemical treatment on disappearance of dry matter (DM), starch and CNCPS carbohydrate fractions. For barley grain treatment, NaOH, formaldehyde and urea were used at 35, 4 and 35 gr/kg DM respectively. Three mature rams (one year old) of Zel breed were rumen cannulated to calculate ruminal disappearance (percent) of DM and starch. Incubation time of nylon bags were 0, 2, 4, 6, 8, 12, 24 and 48 hours. To evaluate CNCPS carbohydrate fraction characteristics, its parameters were measured. Rumen content disappearance results indicated that NaO¬¬¬¬H and formaldehyde treatment had protective effect on DM and starch from rumen digestion leading to better results rather than urea treatment and control groups. Also, starch disappearance of hulled barley was lower than hull-less barley (P<0.05). Chemical treatment of barley grains significantly affected CNCPS carbohydrate fraction characteristics. Each chemical treatment method (in comparison to control) had significant decreasing effects on high speed degradation of such fractions as A and B1 (P<0.05). C fraction or indigestible fiber in hulled barley (with no treatment) was maximum (1.00%) exhibiting had significant difference with those treated with formaldehyde and urea (P<0.05). Therefore based upon the obtained results, rumen content disappearance showed its most effectiveness of NaOH and formaldehyde groups rather than urea and control, but CNCPS fractions were not significantly affected by different chemical processings.

Three hundred eighteen young Holstein bulls (initial BW = 375 ± 17.5 kg) were randomly allotted to one of six treatments in a completely randomized design for 56 d the treatments of which consisted of 1) the basal diet (control); 2) basal diet plus 30 mg of Cu/kg of DM as CuSO4; 3) basal diet plus 150 mg of Zn/kg of DM as ZnSO4; 4) basal diet plus chlortetracycline (200 mg/animal/d; CTC); 5) basal diet + Cu + CTC; and 6) basal diet + Zn + CTC within the same dose. Effects of treatments on blood metabolites and Back fat thickness, Rump fat thickness, Longissimus muscle area and Hip height were evaluated. Serum urea nitrogen (P < 0.001) and plasma total protein (P < 0.001) were different among treatments. Copper supplementation improved ultrasound index, however, zinc supplementation negatively affected (P < 0.001). As a result, the control of Cu and Zn levels, as replacers for CTC, in the diet of young bulls can increase Longissimus muscle area and can decrease fat thickness.

To study the possible use of phytase and yeast (Saccharomyces cervisiae) in corn-soy bean meal base diet with different levels of available phosphorous in Arbor Acers broiler chicks, an experiment was conducted with 264 day old chicks of an average weight of 44.6 grams each. A completely randomized design of 6 treatments and 4 replications (11 chicks per replicate) for periods of starter, grower as well as for the total period of feeding system was employed. Experimental diets were balanced to contain equal levels of energy and protein but available phosphorous concentration differed for control diet which was based on NRC recommendation while for other diets, it was 50 percent below NRC recommendations. Other nutrients were balanced on the bases of energy concentration levels. Treatments were T1) control, T2) control + 500 units of phytase + 0.1 percent yeast, T3) control diet containing 50 percent available phosphorous according to NRC recommendations, T4) control diet containing 50 percent available phosphorous (NRC recommendation) + 0.1 percent yeast, T5) control diet containing 50 percent available phosphorous (NRC recommendation) + 500 unit phytase, T6) control diets containing 50 percent available phosphorous (NRC recommendation) + 500 unit phytase + 0.1 percent yeast. Daily feed intake, live weight gain, feed conversion ratio, calcium and phosphorous concentrations of blood serum were assessed. Results indicated that the decrease in available phosphorous by 50 percent in control diet (T3) caused a significant decrease in feed intake and live weight gain in comparison with respect to control [either with or without phytase and yeast (P<0/05)]. The most suitable FCR was obtained in control (T1) and use of phytase and yeast in control diet (T2) while control diet containing 50 percent available phosphorous (T3) exerted no effect on FCR. Concentrations of blood serum calcium were similar in all diets but phosphorous concentration during periods of 21 and 42 in control diets [containing 50 percent available phosphorous (T3, T4, T5 and T6)] significantly (p<0.05) decreased in comparison with control diet along with phytase and yeast (T2). The overall results indicated that the use of phytase and yeast in control diets and in control diets plus 50 percent content of available phosphorous are not recommended.

This experiment was carried out to study effect of supplementary multi enzyme (0, 4 gr per 100 kg of diet) to corn-soybean meal based diets with different levels of Tomato Pomace (TP, 0, 2, 4, 6 and 8 %, respectively) on chick performance and carcass traits. Four hundred and eighty 480 day-old chicks (Ross-308) were employed [four replicates (n=20)] in a completely randomized experimental design of a factorial arrangement of 2×5. The results revealed that in starter stage the addition of 6% TP to diet significantly decreased weight gain in comparison with control. Feed intake and conversion ratio were greater (p<0.05) in broilers fed with 8 and 6% TP in comparison with control. Although feed consumption, weight gain and feed conversion ratio were not different among treatments in grower and weight gain in the total period, but feed intake and conversion ratio were significantly affected by inclusion of TP (p<0.05). The supplementation of enzyme (during the total period) exerted a significant effect on weight gain and feed conversion ratio (p< 0.05), but the cumulative feed consumption was not significantly affected by the enzyme. The different levels of TP significantly affected the breast (p< 0.05), but had no significant effect on carcass and thigh percentages. The results of the study indicated that the addition of multi-enzyme to diets (0, 2, 4, 6 and 8 % of TP) in comparison with no enzyme addition caused the improvement performance of broiler chicks, suggesting the use of 4% TP plus enzyme recommended in broiler diets.

The effect of Gonadotropin Releasing Hormone (GnRH) on follicular wave emergence in cows with cystic ovaries was investigated. The estrous cycles of 10 cows were synchronized with 2 im injections of prostaglandin F2? given 11 days apart. The cows were randomly assigned to 1 of 3 treatments. Control cows (n=5) received no injection, whereas GnRH cows (n=5) received a GnRH injection on day 6 of the estrous cycle (day of injection=day 0). In cows with cystic ovaries (n=5), diagnosis of a cyst was based on the palpation per rectum of an abnormally large (> 20 mm) follicle and no corpus luteum with these cows then receiving a GnRH injection. The ovaries were scanned through daily ultrasonography from 4 days before (day -4) the day of GnRH treatment (day 0) until 4 days after GnRH treatment (day 4). Daily ultrasonography confirmed the presence of a cyst for at least 10 days in the ovary of the cystic cows. These cows then received a GnRH injection (day 0). The follicles were classified as 4 to 6 mm (small), or? 7 mm (large) follicles. Data were analyzed using the GLM procedure of SAS. In control group, the number of small follicles tended to decline until day 2 of the experiment. Following GnRH injection (day 0) in groups GnRH and cystic cows, the number of small follicles increased until day 2. The number of large follicles in control group did not decrease, however, these classes of follicles decreased (P<0.05) until day 2 in the GnRH and cystic cows. An increase in the number of 4 to 6 mm follicles, 2 days following GnRH injection showed that GnRH treatment could promote the emergence of a new follicular wave in cystic cattle similar to the normal cyclic cattle.

Test day milk records of a Holstein dairy farm collected during years 2004 to 2006 on 142 cows in the 1st lactation vs. 140 cows in the 2nd lactation were used in this research. There were real milk yields of cows available in each part of lactation in this farm making it possible to compare functions based on the new criteria (squared error of estimation). Five functions were compared to estimate production records during each month of lactation, using test day records. These functions were incompelete gama, polynomial regression, inverse polynomial, Wilmink and mixed log function. These functions were compared with third order legender polynomial function for an estimation of total lactation milk yield (305 day milk yield). The criterion for comparing these six functions was the squared error of estimation. Functions were ranked through Quad test on squared error. The first rank in the 1st lactation belonged to incomplete gama function in the 1st, 2nd, 4th, 5th, 8th, and 9th month, polynomial regression function in the 3rd, and 6th month, mixed log function in the 7th month while Wilmink function in the 10th month of lactation. The first rank in the 2nd lactation belonged to incomplete gama function in the 1st, 4th, 5th, 6th, and 9th month, mixed log function in the 7th, and 8th month, while Wilmink function in the the 3rd, and 10th month and polynomial regression function in the 2nd month of lactation. Incomplete gama function won the first rank for estimation of total milk yield (305 day milk yield) in the 1st, 2nd lactation. In the 1st lactation, difference between Incomplete gama function and polynomial regression, third order legender polynomial function and in the 2nd lactation the difference between incomplete gama function and polynomial regression functions were significant.

The purpose of this descriptive– survey research was to identify areas of applying Information Technology in dairy cattle farm management in Western Tehran Province. The statistical population of the study consisted of 284 dairy cattle farmers, out of whom 82 dairy cattle farmers were selected as study sample using Cochran Formula and Proportionate Stratified Sampling Technique. The sample size was later increased to 103 dairy cattle farmers for further enhancing the precision of the study. A questionnaire was employed as the main tool of the study. The validity of the questionnaire was approved by the judgment of a panel of faculty members of the Department of Agricultural Extension Education considered as experts. In order to measure the reliability of the questionnaire, Cronbach Alpha coefficients were calculated for the main scales of the questionnaire which ranged from 0.94 to 0.97 indicating the reliability of the tool of the study. The data were analyzed through SPSS-win software. To identify the areas of applying Information Technology in dairy cattle farm management, factor analysis was applied. The results revealed that milk production management, information seeking & implementation of the official affairs, as well as E commerce extracted from factor analysis, explained 69.25 percent of the total variance.

This experiment was conducted to determine the effects of different levels of anion-cation (67, 117, 167, 217, 267, 317, 367, 417 mEq/kg diet and drinking water) on eggshell quality as well as performance in laying hens at cyclic heat stresses (19-36?C). A total of one hundered and sixty white leghorn laying hens, strain Hy-line W-36 at 63 of weeks age were randomly allotted to 8 dietary treatments Five hens each in 4 replicates were considered in each cage. The experimental period lasted for 60 days. Variation in levels of anion-cation basal diet (Na+ + K+ - Cl-) were obtained by use of supplements sodium bicarbonate (NaHCO3) and calcium chloride (CaCl2). Egg weight, egg production, feed conversion ratio and egg output significantly differed (P<0.05) among treatments. Improvement in all the mentioned traits except in feed consumption were observed as a result of supplementing control diet (167mEq/kg) with 0.42% NaHCO3 (167mEq/kg). Levels of anion-cation did not affect shell thickness, shell percentage, eggshell strength and Haugh unit. All the measured factors were significantly differed (P<0.05) among duration times but did not have any effect on Haugh unit.