Hossein Khoshroo; Hossein Naeemipour; Seyed Homayon Farhangfar; Hadi Sarir
Abstract
Objective: Birth weight is expected to be correlated with future productive and reproductive traits. Several studies have examined the association between birth weight (BW) of Holstein cows and their productive and reproductive traits. In fact, BW is expected to be associated with some of productive ...
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Objective: Birth weight is expected to be correlated with future productive and reproductive traits. Several studies have examined the association between birth weight (BW) of Holstein cows and their productive and reproductive traits. In fact, BW is expected to be associated with some of productive and reproductive traits. The main objective of this research was to conduct a genetic analysis of BW and to evaluate its association with some future productive and reproductive traits of Holstein cows in Isfahan province.
Method: A dataset of 51,427 records of dairy cows in 82 herds of Isfahan province during the calving years from 2001 to 2023 was used in this research. The considered traits were BW, 305-day milk yield (MY), 305-day fat yield (FY), 305-day protein yield (PY), days to first service (DFS), days open (DO), number of services per conception (NSPC), and age at first calving (AFC). Genetic analysis was performed using a series of bivariate animal models. Fixed effects of herd, calving year, calving season, and age at first calving, along with the random additive genetic effect were included in the model. The model was fitted to the data using DMU software.
Results: Mean BW (± SD) of female calves was 39.05± 4.52 kg. The mean values for MY, FY, and PY traits were 11432± 1731, 324.09± 90.63, and 301.26 ± 68.74 kg, respectively. The mean values for reproductive traits, including DO, DFS, AFC, and NSPC were 122.8 ± 45.35, 68.55± 21.09, 726± 59.19 day, and 1.64± 0.95, respectively. Heritability estimates for BW of female calves, MY, FY, and PY were 0.24, 0.26, 0.36, and 0.39, respectively while the heritability estimates for AFC, NSPC, DFS , and DO were 0.15, 0.08, 0.08, 0.02, and 0.02, respectively. Overall, BW of calves had low phenotypic and genetic correlations with their future productive and reproductive traits. Phenotypic and genetic trends for BW were found to be -0.26 ± 0.03 kg per year and 0.024 ± 0.005 kg per year, respectively, which were statistically significant (P < 0.01). The findings of the present research indicated that one kilogram increase in BW of Holstein calves was associated with an increase of 33.77 kg, 0.79 kg, and 0.814 kg for MY, FT, and PY, respectively. Additionally, DFS, DO, AFC, and NSPC in the first lactation period increased by 0.151, 0.115, 0.992 day, and 0.155, respectively.
Conclusion: Current research findings showed that BW gain in female calves is predicted to improve productive and reproductive traits in dairy cows. The positive genetic trend for BW suggests that BW genetically increased over the time of period, which implies that this trait has been selected directly or indirectly over the time of period. The moderate heritability estimate of BW suggests that rapid genetic change of BW could affect economically important traits, and hence, a multiple trait selection index is required to design a balanced breeding program for the economic traits.
Faezeh Khani; Ali Assadi-Alamouti; Behzad Khorrami
Abstract
Objective: Due to increasingly adverse climatic conditions, livestock producers in Iran are experiencing challenges with forage supply. Barley (Hordeum vulgare) is a suitable cereal crop for intercropping with forage pea (Pisum arvense L.), as it can supply a significant portion of the protein demand ...
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Objective: Due to increasingly adverse climatic conditions, livestock producers in Iran are experiencing challenges with forage supply. Barley (Hordeum vulgare) is a suitable cereal crop for intercropping with forage pea (Pisum arvense L.), as it can supply a significant portion of the protein demand for growing livestock and dairy cows with a reasonable protein yield per hectare. Given the benefits of legume-cereal forage intercropping and the national trend toward winter cropping for forage production, the legume-cereal ratio in forage crop mixtures is critical to achieving maximum agronomic performance, water use efficiency, nutritional value, and livestock utilization. Thus, the objective of this study was to evaluate the impact of various proportions of whole-crop barley to forage pea on silage fermentation quality and digestibility.
Methods: Whole crop barley and forage pea were harvested at specific growth stages (early dough stage for barley and mid-flowering to late flowering/early pod formation for forage pea). The experiment comprised four treatments: 1- 100% barley silage, 2- 80% barley+ 20% forage pea silage, 3- 70% barley+ 30% forage pea silage, and 4- 60% barley+ 40% forage pea silage, each with three replicates in a completely randomized design.
Result: Increasing the proportion of forage pea led to a reduction in dry matter and an increase in pH, and significantly increased crude protein and crude ash contents, while not affecting the values of crude fat, acid detergent fiber, neutral detergent fiber, lignin, and acid detergent insoluble nitrogen. Also, increasing the proportion of forage pea significantly elevated the percentage of ammonia nitrogen in the silage. The acetic, propionic, and butyric acid concentrations of all silages were not significantly different and were within the range of well-fermented silages. A mixed silage of 20% forage pea had a higher gas production volume, organic matter digestibility, metabolizable energy, and short-chain fatty acids compared with forage barley ensiled as the sole crop (P<0.05).
Conclusions: The results showed that the addition of forage pea to barley silage increased crude protein and reduced fiber, while maintaining the dry matter and water-soluble carbohydrates advantage of barley forage. This method may be an economically viable method in hot climates to enhance feed quality, reduce costs, and be environmentally sustainable. The results of the present study indicated that a 20% inclusion level of forage pea mixed with barley forage is recommended; however, the optimal intercropping ratio of barley-pea forage will be confirmed by further research on the animal performance in conjunction with the results of the agronomic performance of the mixed-crop silages.
Mahdi Nasrabadi; Khalil zaboli
Abstract
Objective: The suckling calf is particularly susceptible to digestive and respiratory disease because of its immature immune system and increased mortality, making it one of the major challenges of the livestock industry. The nutritional strategy to enhance the performance of suckling calves by supplementing ...
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Objective: The suckling calf is particularly susceptible to digestive and respiratory disease because of its immature immune system and increased mortality, making it one of the major challenges of the livestock industry. The nutritional strategy to enhance the performance of suckling calves by supplementing their diet with feed additives, such as probiotic and biochar, was evaluated in this study.
Method: Twenty-eight female newborn Holstein calves (41.2 ± 3.8 kg) were used in a 2×2 factorial arrangement within a completely randomized design over a 70‑day experimental period. Experimental treatments were as follows:1- basal diet without additive (control), 2- basal diet with 2 g/day of probiotic, 3- basal diet with 1% biochar and 4- basal diet with 2 g/day of probiotic plus 1% biochar. The basal diet was formulated with a 10:90 forage-to-concentrate ratio to meet nutrient requirements. Water and starter feed were provided ad libitum throughout the experiment. Feed intake was recorded daily, body weight and skeletal growth changes were assessed every two weeks. Blood samples were collected on days 0 (birth time), 35 and 70, and fecal samples were collected to evaluate diet digestibility in the last week of the experiment from all calves. All calves were observed for three days at the end of the experiment to record their feeding behaviors (standing, lying, eating, and ruminating) and non-feeding behaviors (licking, sucking, and chewing on environmental objects).
Results: Results indicated that calves that were supplemented with dietary biochar had significantly higher starter feed intake and weaning body weight compared with the non‑biochar groups (P<0.05). Wither height, hip height and abdominal circumference of the calves also increased with biochar supplementation (P<0.05). Concurrent supplementation with probiotic and biochar (treatment 4) further enhanced wither height and hip height (P<0.05). probiotic and biochar supplementation improved apparent digestibility of organic matter and crude protein (P<0.05), respectively, whereas the digestibility of other nutrients was unaffected by experimental treatments. Biochar supplementation also increased blood glucose concentration (P<0.05). Dietary treatments did not significantly affec any of the feeding behaviors. Interaction effects of probiotic and biochar were not significant on any of the parameters measured in this study.
Conclusions: Overall, dietary supplementation with biochar, either alone or in combination with probiotic, showed significant positiv effects on performance, skeletal growth indices, and digestibility of nutrients in suckling calves, suggesting that biochar may be used as a functional feed additive to support early-life health and productivity.
Pooria pezeshknejad; mohammad asadi; shoheil mirhabibi
Abstract
Objective: the Golestan Province has rangelands of high value but these are threatened by climate change and human activities that can lower productivity and ecosystem function. Since soil is the primary substrate for supplying mineral elements to the soil-plant-livestock food chain, assessing the status ...
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Objective: the Golestan Province has rangelands of high value but these are threatened by climate change and human activities that can lower productivity and ecosystem function. Since soil is the primary substrate for supplying mineral elements to the soil-plant-livestock food chain, assessing the status of macro and micro-elements within this system is of special interest. Recent field studies indicate that there may be metabolic disorders in the sheep of the region, which may be caused by mineral deficiencies at various levels of this food chain. The present study was aimed at investigatingthe association ofthe minerals in the soil and forage of rangelands Golestan Province with the serum element levels in lactating Dall lambs and also correlating the levels of these elements across different matrices and to determining the effect of environmental factors on their bioavailability.
Method: The present study was conducted in June 2024 in Golestan Province, Iran. Fifty soil samples were collected from five different areas of the province (Maraveh Tappeh, Incheh Borun, Ghaleh Miran, Chahar Bagh, and Gomishan). Fifty samples of mature rangeland forage, containing a uniform mixture of forage species from the area and a dry weight of 50 g, were harvested, packaged, and transferred to the laboratory to measurethe target elements. To determine serum element concentrations in sheep, blood samples were taken from 50 heads of Dalagh sheep in the study areas (10 per area) and sent to the laboratory. The data were statistically analyzed in a completely randomized design with 5 treatments and 10 replications using SAS 9 software (Tukey; P<0.05). Pearson correlation analysis was performed using R software (version 4.5.1).
Results: Soil analysis results indicated the macro-elements calcium (P=0.0001), magnesium (P=0.0001), potassium (P=0.0311), and sulfur (P=0.0017), differed significantly among rangelands and were more sensitive to to ecological and soil characteristics of the regions, whereasonly phosphorus concentration (P=0.0033) differed significantly among rangelands in forage analysis and theother macro and micro-elements were in the same range and were not significantly different among the rangelands. Concentration of elements in animal blood serum also reflected this pattern, except for calcium (P=0.0217) and phosphorus (P=0.0011) which were significantly differentamong rangelands. Correlation analysis indicated that the correlation pattern between mineral elements in the soil-forage-animal serum chain was not consistent and varied based on element type. The metallic micronutrients (iron, zinc, copper, and manganese) showing stronger and more consistent correlation coefficients among soil, plant, and animal blood serum than the macro-elements, and correlations for macro-elements were generally weaker and more variable within this chain.
Conclusion: Among the rangelands studied, based on the general pattern of mineral elements in soil, forage, and blood serum, the Ghaleh Miran and Gomishan rangelands were more stable and balanced in terms of mineral concentration throughout the soil-forage-serum chain, while the Chahar Bagh rangeland, although some elements were available in soil and forage, had a macro-element imbalance (e.g., calcium-to-phosphorus ratio) at the serum level in animals, possibly due to absorption or homeostatic regulation of these elements in livestock.. The Ghaleh Miran and Gomishan rangelands, on the other hand, had more favorable conditions, whereas the Maraveh Tappeh and Incheh Borun rangelands showed greater fluctuations and a less stable pattern in the concentration of some elements, and the Chahar Bagh rangeland displayed a different pattern with regard to mineral balance at the animal serum level. The results support the conclusion that the stability and biological balance of the mineral transfer chain is more important than soil richness in determining the health and efficiency of this chain in rangelands.
Mohammad Sedghi; zahra sarrami; Razie ghasemi; Mojtaba Abbasi; Ishmael Mohammadi
Abstract
Objective: In recent years, the poultry industry has shown increasing interest in low-protein diets due to their economic and environmental benefits, including reduced feed costs and lower nitrogen excretion. However, reducing dietary protein levels may lead to deficiencies in essential amino acids. ...
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Objective: In recent years, the poultry industry has shown increasing interest in low-protein diets due to their economic and environmental benefits, including reduced feed costs and lower nitrogen excretion. However, reducing dietary protein levels may lead to deficiencies in essential amino acids. Therefore, extensive research over recent decades has focused on evaluating the relationships between dietary nutrients, production performance, and nutritional requirements of broiler chickens, particularly metabolizable energy, protein, and essential amino acids. The primary objective of these studies has been to provide more accurate estimations of nutritional requirements to maximize the genetic potential for growth and performance in poultry.
Method: To investigate the effects of dietary metabolizable energy, protein, methionine+ cysteine, and lysine levels on performance and physiological responses of Arian broiler chickens, a total of 2,160 one-day-old chicks (mixed sex) were used in a 4×4×4×4 factorial experiment with 16 treatments, 5 replicates per treatment, and 27 birds per replicate. Nutrient levels were formulated at 97, 100, 103, and 106% of the recommended requirements according to the Arian catalog. Performance parameters, including body weight gain, feed intake, and feed conversion ratio (FCR), were recorded. At 35 days of age, blood samples were collected from one bird per replicate for the serum biochemical parameters (cholesterol, triglycerides, HDL, LDL, albumin, globulin, ALP, AST, and ALT). Antibody titers against sheep red blood cells (SRBC) were measured at 28 and 35 days of age. At the end of the experimental period, five birds per treatment were slaughtered to determine carcass, liver, and lymphoid organ weights. Additionally, intestinal tissue samples were collected from one bird per replicate to evaluate micromorphological traits, including villus height and width, crypt depth, villus height to crypt depth ratio, and muscular layer thickness.
Results: The results of statistical analysis indicated that the optimal nutrient levels for maximizing daily weight gain over the entire rearing period were 103% of energy and lysine requirements, 106% of protein requirements, and the standard level of methionine+ cysteine. Standard levels of energy and protein, 97% of methionine +cysteine requirements, and 103% of lysine requirements were optimal for feed intake. Increasing dietary energy and protein levels improved the FCR and the European production efficiency index. Serum cholesterol and triglyceride concentrations increased with increasing dietary energy levels. Higher dietary energy with lower protein levels resulted in higher HDL concentrations. Higher levels of energy and protein elevated serum total protein, globulin, and the activities of AST and ALT enzymes. Moreover, dietary lysine level affected villus height and surface area.
Conclusion: Overall, the results of the present study indicate that feeding more than 103% of metabolizable energy required may have detrimental effects on performance and feed intake. Whereas, increasing dietary protein up to 106% of the requirement improved performance; but since there was no significant difference in performance at 103% and 106% protein levels, 103% protein is economically recommended. Furthermore, for optimal performance in Arian broiler chickens, the recommended standard level of methionine+ cysteine and 103% of lysine requirements are also suggested.
Ali Reza Ghiasvand; Hassan Shirzadi; Hossein Ali Ghasemi; Kamran Taherpour; Shokoufeh Hasanvand; Ali Khatibjoo
Abstract
Objective: The aim of this study was to determine the optimal arginine level in the diet of Japanese quails (Coturnix coturnix japonica) and to evaluate its effect on growth performance, feed efficiency, and carcass yield using broken-line and quadratic regression models.
Method: 600 twenty-one-day-old ...
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Objective: The aim of this study was to determine the optimal arginine level in the diet of Japanese quails (Coturnix coturnix japonica) and to evaluate its effect on growth performance, feed efficiency, and carcass yield using broken-line and quadratic regression models.
Method: 600 twenty-one-day-old Japanese quail chicks were randomly assigned to five treatments with digestible arginine levels of 0.75%, 1.00%, 1.25%, 1.50%, and 1.75%, with six replicates per treatment and 20 quails per replicate. The experimental diets were similar in all essential nutrients except for arginine. The experiment was conducted from day 21 to day 35, and during the experimental period, the effects of different arginine levels on body weight (BW) gain, feed efficiency, carcass yield, and the chemical composition of breast and thigh meat were measured.
Results: Results indicated that arginine affected BWG and feed efficiency (P<0.05) of the quails, with the 1.25% arginine treatment being significantly different than the 0.75% and 1.00% treatments and having no difference with the 1.50% treatment (P<0.05). No treatment effect was observed for feed intake, suggesting that greater arginine levels improved the efficiency of feed utilization due to increased BW gain. Arginine requirement was estimated using both broken-line linear and quadratic regression models, with the broken-line linear model with a single slope identifying breakpoints at 1.15% for BW gain and 1.21% for feed efficiency, whereas the quadratic broken-line model predicted breakpoints at 1.30% and 1.29%, respectively. The quadratic regression model predicted that the highest BW gain occurred at 1.37% arginine and the highest occurred at 1.36% arginine. For carcass yield, the 1.25% arginine treatment yielded the highest carcass yield on day 35, which was significantly different than the 0.75% and 1.75% treatments. Both broken-line and quadratic regression models suggested that the optimal level for carcass yield was 1.12% and 1.26% and 1.32% arginine, respectively.
Conclusions: The results of this study indicate that broken-line linear and quadratic regression models can be used to accurately estimate the arginine requirement in the diet of Japanese quails, and the optimal arginine level for improving growth performance and carcass yield in Japanese quails was found to be within the range of 1.15% to 1.37%, whichcan serve as a reference for improving dietary formulations in the quail farming industry and lowering feed costs.
vahid mohammadi; Shokoofeh Ghazanfari; Abdullah Mohammadi Sang-Cheshmeh
Abstract
Objective: Trace elements, particularly zinc (Zn), play a pivotal role in the metabolic processes and growth of broiler chickens. Recent technological advancements have facilitated the synthesis of novel Zn complexes engineered for enhanced nutrient delivery. Consequently, this study was designed to ...
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Objective: Trace elements, particularly zinc (Zn), play a pivotal role in the metabolic processes and growth of broiler chickens. Recent technological advancements have facilitated the synthesis of novel Zn complexes engineered for enhanced nutrient delivery. Consequently, this study was designed to evaluate the effects of various dietary Zn sources on growth performance, carcass characteristics, immunological parameters, and the lipid oxidative stability of broiler meat.
Method: A total of 200 one-day-old Ross 308 broiler chicks were randomly distributed into five experimental treatments, each with four replicates. The treatments consisted of a basal corn-soybean meal diet (Control) or the basal diet supplemented with 40 mg/kg of Zn-sulfate, Zn-methionine, Zn-nano sulfate, or Zn-nano methionine. Feed and water were provided for ad libitum consumption. Environmental temperature and relative humidity were strictly regulated within optimal ranges. Assessments included growth performance, carcass traits, hematological profiles, and thigh meat quality. The nano-complexes were engineered utilizing nano-chelate technology.
Results: At the end of the starter period, the lowest feed intake (FI) was observed in birds supplemented with Zn-nano sulfate (P<0.05). This reduced FI resulted in diminished growth during this phase, showing a significant difference compared to the other groups (P<0.05). Over the entire experimental period (days 1 to 42), a numerical trend toward increased body weight gain (BWG) was noted among treatments (P=0.06). The most favorable feed conversion ratio (FCR) was recorded in the Zn-nano methionine group, which differed significantly from the Control and Zn-nano sulfate groups (P<0.05). Carcass yield was significantly affected by the treatments (P<0.05), with the lowest yields observed in the Control and Zn-nano sulfate groups. Furthermore, the relative weight of the abdominal fat pad was significantly higher in the Control and Zn-nano sulfate groups compared to other treatments (P<0.05). Dietary Zn sources also significantly influenced serum lymphocyte percentages (P < 0.05); the most robust cell-mediated immune response was observed in birds fed Zn-nano methionine and Zn-methionine. Regarding oxidative stability, the extent of lipid oxidation in thigh meat from the Control group was significantly higher at 50, 100, and 150 minutes post-mortem compared to all other treatment groups (P<0.05).
Conclusion: In conclusion, supplementation of broiler diets with 40 mg/kg of nanoscale Zn sources, particularly Zn-nano methionine and Zn-nano sulfate, differentially influenced growth performance, selected immunological traits, and meat quality.
Milad Rostami; Arash Kheradmand; Majid Masoudi Fard
Abstract
Objective: Due to the economic losses caused by mammary gland diseases in ruminants, a quick and accurate diagnosis of is necessary and new, precise and rapid techniques such as ultrasonography should be employed . Ultrasonography has the advantage of being non-invasive and can be used to study a variety ...
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Objective: Due to the economic losses caused by mammary gland diseases in ruminants, a quick and accurate diagnosis of is necessary and new, precise and rapid techniques such as ultrasonography should be employed . Ultrasonography has the advantage of being non-invasive and can be used to study a variety of mammary gland structures. Using of "Water bath" and dipping of udder within the water is the primary ultrasonic mothod with high resolution in order to diagnostic study of different structures of udder and teat. This method causes the teat to be without any under pressure and therefor prevents teat deformity upon examination. Thus, the teat remains in its normal form, and ultrasonographic images acquired will be the most clear and resoulative.
Method: The objective of this study was to compare udder and teat in pregnant and non-pregnant native goats, and right and left quarter in each udder. In this respect, 50 slaughtered native goats at the Golshan slaughterhouse of Khorramabad were sampled and divided into two groups of pregnant and non-pregnant udder (25 samples in each group) based on the presence of the embryo in the uterus and isolated from them. Ultrasonography of udder and teat were performed using a water bath and a linear probe at frequency of 7.5 MHz. All samples were examined and two groups of specimens were measured using the ruler option of the instrument. Udder cistern diameter, teat end width, teat cistern depth, teat wall thickness and teat canal length were statistically compared using student t test.
Results: This study found that the measured parameters of the teat cistern depth and teat end width in pregnant goats were significantly different than that of non-pregnant goats (P<0.05), whereas there was no significant difference in the measured parameter of teat wall thickness between pregnant and non-pregnant goats. There were no significant differences between the teat canal length and the udder cistern diameter in the comparison of the quarter leaves of pregnant and non-pregnant goats and in the comparison of right quarter,. Also, there was no significant difference between left quarter and right quarter in any of the measured parameters in both pregnant goats and non-pregnant goats.
Conclusion: Based on the findings of this study, ultrasonography of udder and teat appears to be a promising and practical technique for diagnosis imaging of the health status and/or potential pathological disorders of udder and teat of native goats in the farm or research studies.
Vahid Kalantar; Hamed Najafi Alamdarloo; Seyed Habibollah Mosavi
Abstract
Objective: As a primary source of dietary protein, chicken meat represents a major component of household consumption in Iran. This study investigates the economic and spatial drivers of provincial chicken supply and demand, aiming to provide a robust framework for regionally targeted policy formulation. ...
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Objective: As a primary source of dietary protein, chicken meat represents a major component of household consumption in Iran. This study investigates the economic and spatial drivers of provincial chicken supply and demand, aiming to provide a robust framework for regionally targeted policy formulation. The analysis covers the period between 2002 and 2024
Method: Utilizing provincial panel data, this study models supply and demand functions via traditional panel techniques and spatial econometric frameworks. Based on rigorous specification and diagnostic testing, a fixed-effects estimation approach was adopted. The model incorporates key explanatory variables, including producer prices for live chickens (supply determinants), retail chicken prices (demand determinants), input costs, exchange rates, household income, and red meat prices as a substitute. Furthermore, the analysis computes historical price elasticities to track longitudinal changes in consumer price sensitivity.
Results: Following the preliminary diagnostic tests, the fixed-effects panel model was determined to be the most appropriate framework for analyzing chicken meat supply and demand dynamics. The results indicated that the price of live poultry exerted a significant positive impact on supply. Conversely, while the retail price of chicken meat negatively affected demand, the price of red meat showed a positive correlation with chicken demand, reflecting a substitution effect. Furthermore, spatial analysis confirmed that provincial supply and demand were significantly influenced by spatial dependencies. The identification of positive spatial autocorrelation in supply and negative spatial autocorrelation in demand suggests divergent geographic distribution patterns for these two variables.
Conclusions: This study applied spatial econometric approaches to examine how regional interactions shape Iran’s chicken meat market. The findings showed that both supply and demand were determined not only by within-province economic conditions but also by developments in neighboring provinces, confirming the presence of significant spatial interdependence. The estimated supply function indicated that live chicken prices positively affected supply, whereas higher input costs and exchange rate fluctuations adversely influenced production. On the demand side, household income and the price of red meat, as a substitute good, exerted positive effects on chicken consumption, while the price of chicken meat itself negatively affected demand. Compared with earlier studies that estimated the price elasticity of chicken meat at approximately −0.93-0.93−0.93, the present study found a substantially lower elasticity of about −0.25-0.25−0.25. This finding suggests that chicken meat has increasingly become a necessity in the food basket of Iranian households, with consumers exhibiting lower sensitivity to price changes. As a result, price adjustments in this market are likely to face limited consumer responsiveness. The observed substitution effect between chicken and red meat further indicates that rising red meat prices encourage households to shift their consumption toward chicken. Spatial analysis also revealed convergence in supply, implying that production levels in one province tended to influence those of neighboring provinces. More broadly, the spatial econometric models confirmed that variables such as input prices, exchange rates, and household income played significant roles in shaping provincial supply and demand patterns. Overall, the results underscore the importance of designing region-specific policies that account for spatial linkages rather than relying solely on uniform national interventions. Despite limitations related to data availability and model specification, this study highlights the critical role of spatial factors in formulating more effective, balanced, and context-sensitive policies for Iran’s chicken meat market.
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