Heritability and genetic correlation of production and reproduction traits of Simmental cows

Improvement of production capacity of cattle in terms of increasing the production of milk, milk fat and number of calves, greatly depends on phenotype and genotype variability, heritability and correlation between desirable traits, as well as on the production level of the cattle population. Heritability, as a value expressing and measuring average additive gene effect, is one of the major characteristic of quantitative traits from the point of view of creating genetically high-value cattle populations. Knowledge of the heritability is necessary in the estimation of the beeeding value of cattle and has significant impact on the selection of breeding method. Genetic correlations are very important in indirect selection where changes in one trait are induced through selection of other traits between which a genetic correlation exists. Genetic correlations can be determined in all cases where heritability coefficient can be calculated. This research included 3.461 first calving Simmental cows under control, with lactation concluded within one year. All first-calvers were reared on individual farms in the territory of Republic of Serbia. In this study, heritability and genetic correlations between the the following milk and fertility traits were investigated: duration of lactation (days)- DL, milk yield in standard lactation (kg)- MY, milk fat content in standard lactation (%)- MFC, milk fat yield in standard lactation (kg)- MFY, yield of 4% FCM in standard lactation (kg)- 4%FCM, age at first calving (days)- AC and duration of service period (days)- DSP.Key words: Heritability, genetic correlations, milk yield, fertility, Simmental breed

The most common health disorders and welfare of dairy cows and calves

Three farms of dairy cows (A, B and C) were observed for health disorders of dairy cows and suckling calves. Farm A is farm with tied system of rearing, with 1100 cows, while farms B and C have 400 and 600 cows kept loose with outdoor pens, respectively. Data regarding welfare criteria of dairy cows (health, feeding, housing and behaviour) were collected and analysed through Protocol of Welfare Quality (2009). Health disorders of dairy cows and suckling calves were collected and statistically analysed by chi-square test (X2 test). Welfare of all of three dairy farms were assessed as acceptable, meaning that provided welfare conditions meet the minimum requirements of animals. Principle of provision of good health was rated as acceptable (≥20 points) on farm A, while on farms with loose system (B and C) overall health rated as excellent (≥80 points). Occurrence rate of reproductive, locomotor, skin and claws disorders and digestive and systemic disorders of dairy cows and calves up to 4 months old were very different between three farms (A, B, C) with X2-values of 2901.71, 252.02, 204.08, 1152.31 and 184.23 respectively; α<0.01). According presented data, it is obvious that the majority health problems were observed in tied system of rearing, on farm A, such as reproductive disorders and mastitis, as well as injuries and bad body score and lame cows. The most serious health problems of the calves were diarrhea and bronchopneumonia of different etiology

Methods for determining stress syndrome in beef cattle and its relevance to quality of meat

Methods for determining stress syndrome in beef cattle is of great importance to identify the physiological state of young cattle before slaughter in order for such animals to be properly treated and restored to a normal physiological state. As a consequence of the state of stress prior to slaughter, meat is obtained which is different from normal. These are non-typical post-mortem changes in meat: 'PSE' (pale, soft, exudative) and 'DFD' (dark, firm, dry) meat, 'watery' meat, usually pork, and 'dark' mostly meat of young bulls. Tests were performed on bulls originating from a farm located 50 km from the slaughterhouse and another farm located 150 km from the slaughterhouse. Young bulls were kept in a free system and loading and unloading was done on unloading ramps and animals taken to the boxes using the lane corridor. Also, attention was paid to avoid mixing with unfamiliar animals during transport. The study included 20 males. The same vehicle was used to transport cattle from the farm to the slaughterhouse. The rectal temperature was taken from 20 young bulls, at the time of loading of cattle into a vehicle during transport and immediately before slaughter. The results of measurements of rectal temperature of investigated bulls suggest that prolonging of transport increases the rectal temperature which can serve as an indicator of stress syndrome in bulls. In addition to measuring of rectal temperature as an indicator of bulls' stress syndrome, other methods are still used, such as the measurement of cortisol in saliva and blood, or the latest methods of measuring cortisol in hair. This is the latest method of the 21st century, which can even determine the time of occurrence of stress. This method is the future that will determine whether the stress occurred few days, weeks or even months ago

Lifetime production of high-yielding dairy cows

Lifetime milk production is a key success factor in fulfilling the production potential of high-yielding cows. Lifetime milk production traits are pronouncedly variable. The life expectancy and the length of productive life of dairy cows are repeatedly limiting factors for improving lifetime milk production. Lifetime milk production is greatly depended on age at first calving and the number of lactations during productive life. Previous researches have implied there are real chances for improving the lifetime milk production of high-yielding cows. The goal of this research was to investigate the significance of key systematic factors on the lifetime production of high-yielding Black-and-White cows. The animals included in the sample had different share of Holstein genes. The researchers determined systematic factors that caused some significant phenotypic variations of the investigated trait. The average lifetime milk production was 25,002.66±7,755.39 kg. When observed by cow genotypes, the mean values of the lifetime milk production varied from 27,061.37 kg (73% HF). The differences in lifetime milk production determined among the animals were due to a highly significant (p≤0.01) impact of the bulls - the sires of the cows and the year of culling; the impact of the class of HF genes was significant (p≤0.05), whereas the impact of the reason for culling was non-significant (p>0.05)

The effect of genetic and non-genetic factors on production traits of Simmental cows

This study covered 737 controlled first calving Simmental cows with, lactations concluded within one year. All first calving animals were on the farms of individual farmers in the municipalities of Kragujevac and Mladenovac. The research included the influence of bull sires, year and season of calving on milk yield and fertility. Least squares method was used to determine the average duration of lactation of 323.74 days. For a period of 305 days, heifers produced 3701.67 kg of milk, or 3644.58 kg of 4% FCM. The average production of milk fat was 144.26 kg and milk fat content was 3.88%. The interval from calving to first insemination lasted in average 124.19 days, and the animals were first calved at the age of 789.95 days. The bull sires had a highly significant effect (P0.05) of bull sires. Year of calving had a significant effect (P0.05). Season of calving of cows demonstrated highly significant effect (P0.05) on the production of milk fat, however it had no effect (P>0.05) on the milk fat content, duration of lactation and service period and age at calving

Effect of Saccharomyces cerevisiae supplementation on health and performance of dairy cows during transition and early lactation period

Data concerning the effect of probiotics supplementation on many parameters concurrently at the same cows are lacking. Therefore, the objective of this experiment was to investigate the effects of Saccharomyces cerevisiae feeding on rumen, blood and milk parameters together in high- producing dairy cattle during the transition and early lactation period. Sixteen clinically healthy Holstein cows were divided into 2 groups: a control group of 6 cows and a probiotics-fed group of 10 cows. Rumen fluid and blood samples were collected 21 days before the expected calving as well as 7, 15, 30, 45 and 60 days- in-milk (DIM). Milk yield for each animal was recorded every 2 weeks. Individual milk samples were collected 15, 30, 45 and 60 DIM. Ruminal pH and rumen ammonia nitrogen were significantly lower, whereas total volatile fatty acids were significantly higher in yeast-fed animals compared with controls throughout the study. Serum concentrations of total proteins and globulins were higher, while albumins were lower in the yeast-treated group. Serum glucose levels were significantly higher in yeast-supplemented animals. Serum triglycerides, high density lipoproteins, and low density lipoproteins concentrations were lower, with cholesterol being significantly lower in the treated group. Milk production and milk fat percentage were higher, whereas milk protein percentage and somatic cell count were decreased in yeast-supplemented cows throughout the study. These results suggest that supplementation of S. cerevisiae to dairy cows rations during transition and early lactation period improve their health and milk production parameters

VARIABILITY OF MILK TRAITS IN THE POPULATION OF SIMMENTAL CATTLE IN SERBIA

The work is the presentation of performance data and phenotypes of milk traits of Simmental cows in Serbia. The analysis of quantitative phenotypic parameters was carried out in four breeding areas and on dozen of large and small farms housing and rearing 1370 cows – first calving heifers. The obtained data were analysed using the method of Least Squares and analysis results were obtained by applying mathematical-statistical data analysis using mixed models. Mathematical - statistical analysis of data was performed using linear methods with fixed effects, using the method of Least Squares (LS method). Based on these results, it was established that the breeding area, statistically analysed, caused highly significant deviations (P <0.01) of production traits from the general population average. Calving season has influenced significantly (P<0.05), and the interaction of area and calving season has produced a highly significant variation in milk yield, milk fat and protein (P <0.01)

Studija projekta 'Optimizacija i standardizacija autohtone tehnologije sjeničkog sira sa zaštitom oznake porekla'

Investigations are based on use of natural potentials on the wide region of Sjenica-Pešter highlands. Certain parameters on selected locations are recorded (soil, vegetation, livestock production, technology of milk and cheese production). On selected locations, farms and processing capacities detail researches are carried out relating to soil, artificial and natural grasslands, reproductive and production potential of cattle and sheep, determination of genetic and non-genetic factors affecting milk traits, quantity and quality of milk, proteins, milk fat, lactose, etc., technological and microbiological traits of milk and cheese. Main objectives of this research and development project is to realize scientific -technological solutions in primary livestock production using our own scientific potentials in order to provide increased productivity, increased number of market farmers capable for competitive economy and production on domestic and foreign market with recognized final product with protected geographical origin, in other words - optimization and standardization of native technology of white cheese from Sjenica with protected brand and origin.Istraživanja su zasnovana na korišćenju prirodnih potencijala šireg regiona Sjeničko-pešterske visoravni. U okviru ovih istraživanja obavlja se snimanje i proučavanje određenih parametara na odabranim lokalitetima ( zemljište, vegetacija, stočarstvo, tehnologija mleka i sira). Na odabranim lokalitetima, farmama i preradjivačkim kapacitetima obavljaju se detaljna istraživanja, zemljišta, prirodnih i veštačkih travnjaka i livada, reproduktivnih i proizvodnih potencijala goveda i ovaca, determinacija genetskih i negenetskih faktora na svojstva mlečnosti, kvantitet i kvalitet mleka, proteini, mlečna mast, laktoza i dr.,tehnološka i mikrobiološka svojstva mleka i sira. Osnovni ciljevi ovog istraživačko-razvojnog projekta je da se korišćenjem sopstvenih naučnih potencijala dođe do naučno-tehnoloških rešenja u primarnoj stočarskoj proizvodnji, koja će obezbediti porast produktivnosti, povećanje robnih proizvođača osposobljenih za konkurentnu proizvodnju na domaćem i stranom tržištu sa prepoznatljivim finalnim proizvodom zaštićenog geografskog porekla, odnosno optimizaciju i standardizaciju autohtone tehnologije Sjeničkog sira sa zaštitom oznake porekla

Different Approaches to Assess the Welfare of Dairy Cows with Some Results in Serbia

In this paper, different methodologies for assessing the welfare of dairy cows, such as Animal Needs Index, system of welfare indicators, system of behaviour indicators and the Welfare Quality® assessment protocol for cattle were discussed. Also, the results of the usage of these methodologies in Serbia were analyzed. In the last several years in the country, numerous studies have been conducted about welfare of dairy cattle. State of welfare of dairy cows, on farms with tied and free system estimated by mentioned methodologies was generally acceptable. The major problems in the welfare of cows are insufficient amounts of floor litter, lack of cow access to outdoor runs or pasture, occurrence of lameness, dystocia, downer cow syndrome and mortality, the manifestation of aggression between the animals and improper relationship between stockmen and animals. On the basis of the results, it can be stated that in Serbia only recently enough attention has been paid to monitoring and understanding the current welfare state of dairy cows, which are the first important steps to achieve improvements in practical terms