Ljiljana Samolovac - Academia.edu (original) (raw)
Papers by Ljiljana Samolovac
Milk fat content stands out as a crucial production trait in cows, and this study delves into its... more Milk fat content stands out as a crucial production trait in cows, and this study delves into its variability based on various factors. The research investigated how the housing method (large farm or individual producers), origin (domestic-rearing or imported cows), and calving season collectively impact this trait. Cows reared on the farm exhibited a higher milk fat content compared to those raised by individual producers. Additionally, primiparous cows from domestic rearing displayed lower milk fat content than their counterparts of imported origin. Among primiparous cows on the farm, those calving in the summer and autumn produced the highest milk fat content. Conversely, primiparous cows calving in the spring season and raised by individual producers recorded the lowest milk fat content. The statistical analysis revealed a highly significant influence of calving season, with a noteworthy interaction among housing method and origin on the observed trait. The significance ranged from statistically highly significant (P ≤ 0.01) to statistically very highly significant (P ≤ 0.001).
Archives of Veterinary Medicine
In this review paper, hygienic procedures before, during and after cow milking are discussed. The... more In this review paper, hygienic procedures before, during and after cow milking are discussed. The procedures for maintaining hygienic udders before and after milking, as well as maintaining the hygiene of milking units are described. The description includes the maintenance of milker's hand hygiene, udder disinfection and udder disinfection after milking. It is pointed out that these milking procedures should be carried out in a clean environment and without any disturbance to cows. In addition, the need to control the implementation of these hygiene measures is emphasized. A proper way of carrying out the hygienic procedures essentially contributes to reduction of the number of microorganisms and the number of somatic cells in milk, the frequency of occurrence of mastitis, which significantly affects quality of milk and health of milking cows.
Radovi Poljoprivrednog Fakulteta Univerziteta u Sarajevu Works of the Faculty of Agriculture University of Sarajevo, 2010
Radovi Poljoprivrednog Fakulteta Univerziteta u Sarajevu Works of the Faculty of Agriculture University of Sarajevo, 2010
Biotehnologija u stocarstvu
In the last decades, there has been a trend present in the world to increase the size of dairy he... more In the last decades, there has been a trend present in the world to increase the size of dairy herds while increasing the yield of milk per head. In addition to environmental and economic benefits, this trend carries certain risks for the welfare of cows because in conditions of increased agglomeration of cattle the possibility of spreading of pathogens is also increased, there are less opportunities for adequate control and cows are exposed to greater selection and production stress. Research of the relationship between herd size and welfare quality parameters is still not sufficient to make relevant conclusions. Starting from that, the aim of this study, conducted in Serbia, is to examine the influence of herd size on parameters related to providing good feeding and housing conditions as important segments of the overall welfare of dairy cows. The assessment of given welfare parameters was done by Welfare Quality? Assessment Protocol for Cattle (2009) on 16 dairy farms of differen...
Biotehnologija u stocarstvu
Calcium and phosphorus represent very important nutrients when it comes to poultry diet formulati... more Calcium and phosphorus represent very important nutrients when it comes to poultry diet formulations. In this paper, we will briefly discuss the relevance and nutritional requirements of these minerals in poultry feedstuffs as well as the average amounts in poultry feed commercially sold in the Serbian market. A total of 1,058 samples of standard complete feed mixtures for broilers and laying hens were collected from the Serbian market, produced by the four major Serbian manufacturers (I-IV) of animal feed over a period of five years (2017-2021). The samples were classified into five groups: broiler starter feed (n = 198) - SF, grower feed (n = 239) - GF, and finisher feed (n = 204) - FF; layers feed 1 (n = 204) - LF1, and layers feed 2 (n = 213) - LF2. This research suggests that the mineral composition of poultry feed is highly variable among manufacturers, but also among the batches of the same manufacturers. All manufacturers for the analyte in focus had values for certain batch...
The experiment was set up to examine the effect of adding flax seeds to the cattle diet on the qu... more The experiment was set up to examine the effect of adding flax seeds to the cattle diet on the quality of meat, in the final phase of fattening. Thirty Simmental young bulls of uniform initial body weight were selected for the experiment and divided into 2 groups (CON (control) and LS (experimental)). The control group did not consume flaxseed as a dietary supplement. Flaxseed was added to the experimental group in the amount of 3.75% (300 g per day) of the concentrated part of the meal in the final 90 days of fattening. The research included the examination of certain traits of beef meat quality. The results of the study show that the addition of flaxseed in the diet did not have a statistically significant effect on pH, water binding capacity (WBC), weight loss during cooking and meat tenderness. The chemical composition of the selected muscles, as well as the content of total pigments did not change significantly in the experimental animals compared to the control group. It was f...
The paper describes the effects of different rearing conditions as possible stressors on health, ... more The paper describes the effects of different rearing conditions as possible stressors on health, reproduction, growth, milk yield and quality of meat and milk. It was pointed out that numerous internal and external factors of cattle affect the physiological processes, health, reproduction, growth, milk yield and quality of milk and meat as very strong stressors. They are especially important when acting immediately after parturition, i.e. in the puerperium in cows and immediately after birth in calves. In intensive cattle production, the most important complex stressors regardless of origin, and physiological conditions in which these animals are more susceptible to distress are parturition, calf birth, puerperium, intensive lactation, machine milking, oestrus, high pregnancy, dry period, grouping of animals, disturbed social relations, dehorning, castration, hoof trimming, transport, sudden changes in microclimatic conditions and feed quality, etc. Excessive disturbances before sla...
Intensive cattle farming covers a wide range of technological processes that should enable contin... more Intensive cattle farming covers a wide range of technological processes that should enable continued production and optimal use of production capacity. In such circumstances newborn calves have to adapt to different environmental factors, including diet. The technology of growing calves diet was initially based exclusively on a diet of colostrum and then milk. After that, the food introduced other feed (hay, feed mixture), but after three months the milk completely excluded from the diet. Intensive breeding of calves requires continuous moniitoring of the health condition of calves and adedquate application prophylactic,hygenic and zooterhnical measures.Diseases of the infants can be divided in three groups: inhereted and birth defects non-infectious and deficiency diseases infectious diseases. The most significant of these infants’ disease, which are given special attention are the infectious-contagious diseases Improving the health condition has positive effect on the production r...
Archives Animal Breeding, 2010
Group of secondary traits such as health, longevity, type and milkability represents some of very... more Group of secondary traits such as health, longevity, type and milkability represents some of very important factors for successful milk production. These traits have been given great importance in recent years. In order to realize productive life of dairy cows as long and successful as possible, special attention should be directed to traits of type and body constitution. Objective of the research was to establish heritability coefficients for 14 type traits of first calving Black and White cows, effect of genetic and paragenetic factors (bull sires, farm, year and season of calving, age at scoring and share of Holstein-Friesian [HF] genes) on type traits, so that these scores could be included in calculation of breeding value of the animal. Also, average values of milk traits have been established: milk yield and yield of 4 % fat corrected milk (FCM), content and quantity of milk fat. Evaluation was performed on a sample of 2 976 first calving Black and White cows. Evaluated cows were reared on 7 farms of the Agricultural Corporation Belgrade in Serbia. Analysis of discontinuous and continuous influences was done using the method of least squares. Investigation indicated that the value of linear type evaluation should be included in the total evaluation of the breeding value and in this way complete insight into genetic supremacy, especially of breeding bulls, would be obtained. Use of bull semen of proven supremacy in transmission of genes desirable from the aspect of body constitution, in the process of artificial insemination, would lead faster to production herds with animals which are uniform in type, of good conformation and longevity, which is of special significance in conditions of intensive rearing of dairy cattle.
Biotechnology in Animal Husbandry, 2010
Cows which represent top of the genetic value of the population in regard to their traits are cho... more Cows which represent top of the genetic value of the population in regard to their traits are chosen for bull dams. Selection is based on origin, production performance (quantity of milk, milk fat and protein content), milking/dairy traits, reproductive indicators, exterior and linear type scores. This study included 292 cows of Simmental breed selected for bull dams on the territory of Republic of Serbia during one year. Selection of cows for herd of bull dams was done after finalized first and subsequent lactation. In this study, the effect of region and year of calving on milk traits is presented. Applying the method of least squares average value of milk production was obtained - 5.754,49 kg, milk fat content - 3,98% and quantity of milk fat - 230,24 kg. Regions had statistically highly significant effect (P<0,01) on all investigated milk traits. Year of calving showed no statistically significant effect on milk yield, yield of milk fat and content of milk fat (P>0,05).
The quality of farm animal welfare largely depends on a number of measures and procedures carried... more The quality of farm animal welfare largely depends on a number of measures and procedures carried out on farms, which are defined by one name as biosecurity. The application of certain management practices differs from farm to farm, and accordingly their impact on the quality of animal welfare differs. The quality of biosecurity, welfare and the presence of factors that threaten them depend on the technology of production on the farm, animal husbandry systems, microclimatic and hygienic conditions, management, procedures performed on animals and the way they are performed, the attitude of employees towards animals, their training and competence, etc.The aim of this study was to determine the impact of intensive calf rearing on differences in biosecurity and welfare quality assessment on two dairy farms. The technological process of production on both farms is similar, since both farms operate within the same production system. On both farms, there is a nursery in a separate facility...
Genetika, 2018
This research was conducted with the aim ?f estimating genetic trend for a functional length of p... more This research was conducted with the aim ?f estimating genetic trend for a functional length of productive life (FLPL) in the population of Black and White cattle in Serbia. Research and bulls genetic evaluation for functional longevity were performed on a set of data provided by Agricultural Corporation Belgrade AD (PKB) which contained data on longevity and origin of 22109 cows out of which 26% records were right-censored. Functional length of productive life (FPLP) represents a time period from the first calving to culling or censoring corrected for milk production. Breeding values were estimated using Weibull method of proportional risks within survival analysis a genetic trend for FLPL was calculated using of a regression analysis. The cows included in the analysis were on average first calved in the age of 809 days and had an average share of 81.9% genes of Holstein Friesian breed. An average length of productive life was 1267 days (41.6 months). Distribution of bull standardi...
The objective of this paper was to compare heifers reproductive traits and characteristics of the... more The objective of this paper was to compare heifers reproductive traits and characteristics of their calves after artificial insemination performed by conventional (non-sexed) and sexed sperm on 6 commercial farms in Serbia. Conception rate was 55% and 44% for conventional and sexed semen, an average gestation length being 274.6 and 274.9 days, respectively. Average body mass at birth was 37.47 and 36.75 kg for non-sexed and sexed semen, respectively. The rate of stillbirths and twinning was 6.19 and 3.78% for conventional and 7.54 and 1.13% for sexed semen, respectively. The use of conventional semen exerted no statistically significant (P>0.05) effect on female: male calves relationship (51.96 : 48.04) while artificial insemination by sexed semen highly significantly (P<0.01) changed calf sex-ratio (85.10 : 14.90). First-calf heifers originating from sires whose sperm was obtained in conventional way produced 7880 kg milk with 269 kg milk fat and 242 kg protein in standard la...
Large Animal Review, Mar 10, 2021
This study was carried to determine if dietary tryptophan can be beneficial for piglets in period... more This study was carried to determine if dietary tryptophan can be beneficial for piglets in period of weaning. Trial was conducted on 84 individuals (Landrace×Yorkshire) female and castrated male piglets, at 30 days of age, and of 9.78±0.42 kg. Test subjects were penned into four groups and allocated to four different diets. This was done opposite to standard farm procedure; all piglets penned in same group came from different litters. Animals were fed ad libitum for six days. Piglets in trial groups were fed with basically same mixture with different levels of digestible L-tryptophan (0.1; 0.2; 0.3%). Productive performance (FCR; ADG; ADFI) was calculated and behavior characteristics (postures, mounting, abnormal and aggressive behavior) were observed using CCTV cameras. For the purpose of production performance analysis one way ANOVA was used while the Tukey test served to determine the statistical significance of the differences between individual means values. Considering that there is no normal distribution for behavioral parameters, we used non parametric Kruskal-Wallis test with multiple comparisons of mean rank between groups. Productive results showed that control group had significantly better results for average daily gain compared to all trial groups (p<0.05), other productive parameters didn't show any significant difference. On the other hand, statistically significant results occurred for two behavioral characteristics. Fighting differed significantly (p<0.05), during first day of weaning between control and trial groups, intensive ear biting occurred at day two and three after weaning, and different significantly on day three (p<0.05). According to our results tryptophan had no positive effects on productive performance (feed intake, daily weight gain and feed conversion), but had some positive effects on reducing aggressive behavior. Conclusion could be that implementing small doses of tryptophan on weaning can be beneficial to reducing stress and behavioral anomalies of piglets. Further more extensive studies should be carried to verify these results.
Biotechnology in Animal Husbandry, 2021
The Simmental breed of cattle is mostly reared in the central part of the Republic of Serbia, whe... more The Simmental breed of cattle is mostly reared in the central part of the Republic of Serbia, where it makes up about 80% of all breeds. In areas of more intensive cattle production, populations of cattle with pronounced milk yield are reared. In more extensive, as well as hilly and mountainous areas, somewhat less productive animals are raised. The main goal of this study was to examine the variability of genetic correlations of milk and fertility traits on the farms of individual agricultural producers using modern methods, depending on the breeding area, i.e. the region in which they are bred and reared. This study included 2589 controlled Simmental heifers, with lactations concluded during one year. All first calving heifers were housed and reared on agricultural family farms in the area of Central Serbia. The paper examines genetic correlations between the following traits of milk yield and fertility: duration of lactation, milk yield in standard lactation, milk fat content in ...
Biotehnologija u stocarstvu
Data set including 10860 primiparous Holstein-Friesian breed cows first calved in the period from... more Data set including 10860 primiparous Holstein-Friesian breed cows first calved in the period from 2011 to 2015, was used in determining phenotypic variability and correlation between the traits of milk yield and linearly estimated traits of udder and angularity. The average values obtained for type traits (angularity, fore udder attachment, front teats placement, teats length, udder depth and rear udder height) were 6.47; 5.74; 4.96; 5.20; 5.99 and 6.25, respectively. The values obtained for phenotypic correlations between linear type traits and traits of milk yield ranged from -0.042 (udder depth and milk yield) to 0.335 (fore udder attachment and protein yield). Positive phenotypic correlation (0.293) was recorded also between fore udder attachment and milk yield which is deemed the most important trait of milk yield while the lowest correlation between milk yields was determined in relation to udder depth (-0.033). The results obtained indicate a possibility of applying direct an...
Milk fat content stands out as a crucial production trait in cows, and this study delves into its... more Milk fat content stands out as a crucial production trait in cows, and this study delves into its variability based on various factors. The research investigated how the housing method (large farm or individual producers), origin (domestic-rearing or imported cows), and calving season collectively impact this trait. Cows reared on the farm exhibited a higher milk fat content compared to those raised by individual producers. Additionally, primiparous cows from domestic rearing displayed lower milk fat content than their counterparts of imported origin. Among primiparous cows on the farm, those calving in the summer and autumn produced the highest milk fat content. Conversely, primiparous cows calving in the spring season and raised by individual producers recorded the lowest milk fat content. The statistical analysis revealed a highly significant influence of calving season, with a noteworthy interaction among housing method and origin on the observed trait. The significance ranged from statistically highly significant (P ≤ 0.01) to statistically very highly significant (P ≤ 0.001).
Archives of Veterinary Medicine
In this review paper, hygienic procedures before, during and after cow milking are discussed. The... more In this review paper, hygienic procedures before, during and after cow milking are discussed. The procedures for maintaining hygienic udders before and after milking, as well as maintaining the hygiene of milking units are described. The description includes the maintenance of milker's hand hygiene, udder disinfection and udder disinfection after milking. It is pointed out that these milking procedures should be carried out in a clean environment and without any disturbance to cows. In addition, the need to control the implementation of these hygiene measures is emphasized. A proper way of carrying out the hygienic procedures essentially contributes to reduction of the number of microorganisms and the number of somatic cells in milk, the frequency of occurrence of mastitis, which significantly affects quality of milk and health of milking cows.
Radovi Poljoprivrednog Fakulteta Univerziteta u Sarajevu Works of the Faculty of Agriculture University of Sarajevo, 2010
Radovi Poljoprivrednog Fakulteta Univerziteta u Sarajevu Works of the Faculty of Agriculture University of Sarajevo, 2010
Biotehnologija u stocarstvu
In the last decades, there has been a trend present in the world to increase the size of dairy he... more In the last decades, there has been a trend present in the world to increase the size of dairy herds while increasing the yield of milk per head. In addition to environmental and economic benefits, this trend carries certain risks for the welfare of cows because in conditions of increased agglomeration of cattle the possibility of spreading of pathogens is also increased, there are less opportunities for adequate control and cows are exposed to greater selection and production stress. Research of the relationship between herd size and welfare quality parameters is still not sufficient to make relevant conclusions. Starting from that, the aim of this study, conducted in Serbia, is to examine the influence of herd size on parameters related to providing good feeding and housing conditions as important segments of the overall welfare of dairy cows. The assessment of given welfare parameters was done by Welfare Quality? Assessment Protocol for Cattle (2009) on 16 dairy farms of differen...
Biotehnologija u stocarstvu
Calcium and phosphorus represent very important nutrients when it comes to poultry diet formulati... more Calcium and phosphorus represent very important nutrients when it comes to poultry diet formulations. In this paper, we will briefly discuss the relevance and nutritional requirements of these minerals in poultry feedstuffs as well as the average amounts in poultry feed commercially sold in the Serbian market. A total of 1,058 samples of standard complete feed mixtures for broilers and laying hens were collected from the Serbian market, produced by the four major Serbian manufacturers (I-IV) of animal feed over a period of five years (2017-2021). The samples were classified into five groups: broiler starter feed (n = 198) - SF, grower feed (n = 239) - GF, and finisher feed (n = 204) - FF; layers feed 1 (n = 204) - LF1, and layers feed 2 (n = 213) - LF2. This research suggests that the mineral composition of poultry feed is highly variable among manufacturers, but also among the batches of the same manufacturers. All manufacturers for the analyte in focus had values for certain batch...
The experiment was set up to examine the effect of adding flax seeds to the cattle diet on the qu... more The experiment was set up to examine the effect of adding flax seeds to the cattle diet on the quality of meat, in the final phase of fattening. Thirty Simmental young bulls of uniform initial body weight were selected for the experiment and divided into 2 groups (CON (control) and LS (experimental)). The control group did not consume flaxseed as a dietary supplement. Flaxseed was added to the experimental group in the amount of 3.75% (300 g per day) of the concentrated part of the meal in the final 90 days of fattening. The research included the examination of certain traits of beef meat quality. The results of the study show that the addition of flaxseed in the diet did not have a statistically significant effect on pH, water binding capacity (WBC), weight loss during cooking and meat tenderness. The chemical composition of the selected muscles, as well as the content of total pigments did not change significantly in the experimental animals compared to the control group. It was f...
The paper describes the effects of different rearing conditions as possible stressors on health, ... more The paper describes the effects of different rearing conditions as possible stressors on health, reproduction, growth, milk yield and quality of meat and milk. It was pointed out that numerous internal and external factors of cattle affect the physiological processes, health, reproduction, growth, milk yield and quality of milk and meat as very strong stressors. They are especially important when acting immediately after parturition, i.e. in the puerperium in cows and immediately after birth in calves. In intensive cattle production, the most important complex stressors regardless of origin, and physiological conditions in which these animals are more susceptible to distress are parturition, calf birth, puerperium, intensive lactation, machine milking, oestrus, high pregnancy, dry period, grouping of animals, disturbed social relations, dehorning, castration, hoof trimming, transport, sudden changes in microclimatic conditions and feed quality, etc. Excessive disturbances before sla...
Intensive cattle farming covers a wide range of technological processes that should enable contin... more Intensive cattle farming covers a wide range of technological processes that should enable continued production and optimal use of production capacity. In such circumstances newborn calves have to adapt to different environmental factors, including diet. The technology of growing calves diet was initially based exclusively on a diet of colostrum and then milk. After that, the food introduced other feed (hay, feed mixture), but after three months the milk completely excluded from the diet. Intensive breeding of calves requires continuous moniitoring of the health condition of calves and adedquate application prophylactic,hygenic and zooterhnical measures.Diseases of the infants can be divided in three groups: inhereted and birth defects non-infectious and deficiency diseases infectious diseases. The most significant of these infants’ disease, which are given special attention are the infectious-contagious diseases Improving the health condition has positive effect on the production r...
Archives Animal Breeding, 2010
Group of secondary traits such as health, longevity, type and milkability represents some of very... more Group of secondary traits such as health, longevity, type and milkability represents some of very important factors for successful milk production. These traits have been given great importance in recent years. In order to realize productive life of dairy cows as long and successful as possible, special attention should be directed to traits of type and body constitution. Objective of the research was to establish heritability coefficients for 14 type traits of first calving Black and White cows, effect of genetic and paragenetic factors (bull sires, farm, year and season of calving, age at scoring and share of Holstein-Friesian [HF] genes) on type traits, so that these scores could be included in calculation of breeding value of the animal. Also, average values of milk traits have been established: milk yield and yield of 4 % fat corrected milk (FCM), content and quantity of milk fat. Evaluation was performed on a sample of 2 976 first calving Black and White cows. Evaluated cows were reared on 7 farms of the Agricultural Corporation Belgrade in Serbia. Analysis of discontinuous and continuous influences was done using the method of least squares. Investigation indicated that the value of linear type evaluation should be included in the total evaluation of the breeding value and in this way complete insight into genetic supremacy, especially of breeding bulls, would be obtained. Use of bull semen of proven supremacy in transmission of genes desirable from the aspect of body constitution, in the process of artificial insemination, would lead faster to production herds with animals which are uniform in type, of good conformation and longevity, which is of special significance in conditions of intensive rearing of dairy cattle.
Biotechnology in Animal Husbandry, 2010
Cows which represent top of the genetic value of the population in regard to their traits are cho... more Cows which represent top of the genetic value of the population in regard to their traits are chosen for bull dams. Selection is based on origin, production performance (quantity of milk, milk fat and protein content), milking/dairy traits, reproductive indicators, exterior and linear type scores. This study included 292 cows of Simmental breed selected for bull dams on the territory of Republic of Serbia during one year. Selection of cows for herd of bull dams was done after finalized first and subsequent lactation. In this study, the effect of region and year of calving on milk traits is presented. Applying the method of least squares average value of milk production was obtained - 5.754,49 kg, milk fat content - 3,98% and quantity of milk fat - 230,24 kg. Regions had statistically highly significant effect (P<0,01) on all investigated milk traits. Year of calving showed no statistically significant effect on milk yield, yield of milk fat and content of milk fat (P>0,05).
The quality of farm animal welfare largely depends on a number of measures and procedures carried... more The quality of farm animal welfare largely depends on a number of measures and procedures carried out on farms, which are defined by one name as biosecurity. The application of certain management practices differs from farm to farm, and accordingly their impact on the quality of animal welfare differs. The quality of biosecurity, welfare and the presence of factors that threaten them depend on the technology of production on the farm, animal husbandry systems, microclimatic and hygienic conditions, management, procedures performed on animals and the way they are performed, the attitude of employees towards animals, their training and competence, etc.The aim of this study was to determine the impact of intensive calf rearing on differences in biosecurity and welfare quality assessment on two dairy farms. The technological process of production on both farms is similar, since both farms operate within the same production system. On both farms, there is a nursery in a separate facility...
Genetika, 2018
This research was conducted with the aim ?f estimating genetic trend for a functional length of p... more This research was conducted with the aim ?f estimating genetic trend for a functional length of productive life (FLPL) in the population of Black and White cattle in Serbia. Research and bulls genetic evaluation for functional longevity were performed on a set of data provided by Agricultural Corporation Belgrade AD (PKB) which contained data on longevity and origin of 22109 cows out of which 26% records were right-censored. Functional length of productive life (FPLP) represents a time period from the first calving to culling or censoring corrected for milk production. Breeding values were estimated using Weibull method of proportional risks within survival analysis a genetic trend for FLPL was calculated using of a regression analysis. The cows included in the analysis were on average first calved in the age of 809 days and had an average share of 81.9% genes of Holstein Friesian breed. An average length of productive life was 1267 days (41.6 months). Distribution of bull standardi...
The objective of this paper was to compare heifers reproductive traits and characteristics of the... more The objective of this paper was to compare heifers reproductive traits and characteristics of their calves after artificial insemination performed by conventional (non-sexed) and sexed sperm on 6 commercial farms in Serbia. Conception rate was 55% and 44% for conventional and sexed semen, an average gestation length being 274.6 and 274.9 days, respectively. Average body mass at birth was 37.47 and 36.75 kg for non-sexed and sexed semen, respectively. The rate of stillbirths and twinning was 6.19 and 3.78% for conventional and 7.54 and 1.13% for sexed semen, respectively. The use of conventional semen exerted no statistically significant (P>0.05) effect on female: male calves relationship (51.96 : 48.04) while artificial insemination by sexed semen highly significantly (P<0.01) changed calf sex-ratio (85.10 : 14.90). First-calf heifers originating from sires whose sperm was obtained in conventional way produced 7880 kg milk with 269 kg milk fat and 242 kg protein in standard la...
Large Animal Review, Mar 10, 2021
This study was carried to determine if dietary tryptophan can be beneficial for piglets in period... more This study was carried to determine if dietary tryptophan can be beneficial for piglets in period of weaning. Trial was conducted on 84 individuals (Landrace×Yorkshire) female and castrated male piglets, at 30 days of age, and of 9.78±0.42 kg. Test subjects were penned into four groups and allocated to four different diets. This was done opposite to standard farm procedure; all piglets penned in same group came from different litters. Animals were fed ad libitum for six days. Piglets in trial groups were fed with basically same mixture with different levels of digestible L-tryptophan (0.1; 0.2; 0.3%). Productive performance (FCR; ADG; ADFI) was calculated and behavior characteristics (postures, mounting, abnormal and aggressive behavior) were observed using CCTV cameras. For the purpose of production performance analysis one way ANOVA was used while the Tukey test served to determine the statistical significance of the differences between individual means values. Considering that there is no normal distribution for behavioral parameters, we used non parametric Kruskal-Wallis test with multiple comparisons of mean rank between groups. Productive results showed that control group had significantly better results for average daily gain compared to all trial groups (p<0.05), other productive parameters didn't show any significant difference. On the other hand, statistically significant results occurred for two behavioral characteristics. Fighting differed significantly (p<0.05), during first day of weaning between control and trial groups, intensive ear biting occurred at day two and three after weaning, and different significantly on day three (p<0.05). According to our results tryptophan had no positive effects on productive performance (feed intake, daily weight gain and feed conversion), but had some positive effects on reducing aggressive behavior. Conclusion could be that implementing small doses of tryptophan on weaning can be beneficial to reducing stress and behavioral anomalies of piglets. Further more extensive studies should be carried to verify these results.
Biotechnology in Animal Husbandry, 2021
The Simmental breed of cattle is mostly reared in the central part of the Republic of Serbia, whe... more The Simmental breed of cattle is mostly reared in the central part of the Republic of Serbia, where it makes up about 80% of all breeds. In areas of more intensive cattle production, populations of cattle with pronounced milk yield are reared. In more extensive, as well as hilly and mountainous areas, somewhat less productive animals are raised. The main goal of this study was to examine the variability of genetic correlations of milk and fertility traits on the farms of individual agricultural producers using modern methods, depending on the breeding area, i.e. the region in which they are bred and reared. This study included 2589 controlled Simmental heifers, with lactations concluded during one year. All first calving heifers were housed and reared on agricultural family farms in the area of Central Serbia. The paper examines genetic correlations between the following traits of milk yield and fertility: duration of lactation, milk yield in standard lactation, milk fat content in ...
Biotehnologija u stocarstvu
Data set including 10860 primiparous Holstein-Friesian breed cows first calved in the period from... more Data set including 10860 primiparous Holstein-Friesian breed cows first calved in the period from 2011 to 2015, was used in determining phenotypic variability and correlation between the traits of milk yield and linearly estimated traits of udder and angularity. The average values obtained for type traits (angularity, fore udder attachment, front teats placement, teats length, udder depth and rear udder height) were 6.47; 5.74; 4.96; 5.20; 5.99 and 6.25, respectively. The values obtained for phenotypic correlations between linear type traits and traits of milk yield ranged from -0.042 (udder depth and milk yield) to 0.335 (fore udder attachment and protein yield). Positive phenotypic correlation (0.293) was recorded also between fore udder attachment and milk yield which is deemed the most important trait of milk yield while the lowest correlation between milk yields was determined in relation to udder depth (-0.033). The results obtained indicate a possibility of applying direct an...