High-yielding Cows Research Articles

Оценка типа стрессоустойчивости коров-матерей и их потомков

Abstract. Resistance to stress in cows depends on factors such as age, gender, fatness, body type and heredity. The effects of long-term stress factors on the dairy herd cause hard-to-recover damage during production. The purpose of our research was to assess the types of stress resistance of mother cows and their offspring. Methods. The stress tolerance index of the studied animals was calculated according to the method of N. A. Safiullin and others. This method includes the impact on animals during machine milking of a stress factor and changes in milk production indicators, determining the stress resistance indicator of cows by the average value of the sum of estimated indicators: the ratio of 1 % milk, changes in the intensity and completeness of milk production, the duration of the latent milking period. Results. It was found that the most stress-resistant animals were less productive (8000 kg and less for maximum lactation). The stress tolerance index in the mother cows of this group is on average 0.137 (p < 0.001) higher than in other animals evaluated. At the same time, their descendants also had a stress tolerance index higher than in other evaluated groups by an average of 0.041 (p < 0.01). A high type of stress tolerance was determined in 75.0 % of heads in the group of cows-mothers with the lowest productivity for maximum lactation. Slightly less animals with a high type of stress resistance in the group of their descendants – 33.0 % of heads. At the same time, in these groups of mothers and daughters, cows with a low type of stress resistance were not found at all. Repeatability coefficients indicate that in low-yielding mother cows, the stress tolerance index is repeated in groups of daughter cows to a much lesser extent (at r = 0.26) compared to groups of high-yielding cows. The scientific novelty lies in the fact that the indicators of stress resistance of cows and their offspring are established depending on the highest productivity of mothers.

FEED CONSUMPTION, REPRODUCTIVE FUNCTIONS, RUMEN METABOLISM, DIGESTIVENESS AND NITROGEN BALANCE IN HIGHLY PRODUCTIVE COWS IN THE SECOND PERIOD OF LACTATION FOR THE FERTILIZATION OF MIXED- LIGAND ZINC, MANGANESE AND COBALT COMPLEXES

The presented indicators of feed consumption, reproduction, scar fluid, digestibility of nutrients and average daily balance of Nitrogen in highly productive cows of Holstein, Ukrainian Black-Spotted dairy breed and Ukrainian Red-Spotted dairy breeds in the second period of lactation by feeding them different doses of mixed-ligand complexes of Zinc, Manganese and Cobalt.
 Consumption of feed mixture by experimental animals ranged from 46.2 kg to 52.2 kg. It was best consumed by cows of the 5th experimental group, in the feed mixture of which the concentration of trace elements in 1 kg of DM was: Zinc – 35 mg, Manganese – 35, Cobalt – 0.4, Selenium – 0.3, Copper – 10 mg and Iodine – 0.9 mg. It is set up that the use of different levels of mixed-ligand complexes of Zinc, Manganese and Cobalt reduces the duration of the service period in cows compared with its average value for the herd, which is 145.6 days.
 In the rumen fluid of experimental cows, the pH value was increasing in the alkaline direction and the difference to the control group was statistically significant. It also decreased the content of total nitrogen compared to control, which indicates its better absorption into the blood. At the same time, the content of protein and ammonia nitrogen in the rumen fluid of experimental cows was significantly reduced. The use in the rations of cows in the second 100 days of lactation of different levels of mixed-ligand complexes of Zinc, Manganese and Cobalt did not show a significant influence on the formation of volatile fatty acids in the rumen fluid, however, there was a tendency to increase them at lower concentrations of these trace elements.
 Cows of the experimental groups better digested dry and organic matter, crude protein, crude fat, crude fiber and NFES. The recommended and accepted norms of the dose of microelements used in the control group did not show the highest influence on the coefficients of digestibility of nutrients in feed mixtures compared with their lower doses in the experimental groups.
 It was found that the increase in the transformation of Nitrogen into the milk protein of cows of the experimental groups was contributed by better digestibility and less excretion of Nitrogen in the urine, which is one of the main factors in increasing their milk productivity.
 The elimination of zinc, manganese and cobalt deficiency in the ration of high-yielding cows due to lower doses of their mixed-ligand complexes has a positive influence on the digestibility of nutrients in the ration, nitrogen metabolism and productivity of animals.

Experimental and theoretical studies of milk and air motion in the milk-producing tract of the milking machine

The article provides a theoretical analysis of the process of milk movement from the milk chamber of the collector through the milk hose to the milk pipeline using a continuous model of the plug flow of a two-phase medium. There have been obtained analytic expressions that allow determining the values of pressure drop in the descending and ascending sections of the milk hose. According to the results of the theoretical analysis for two-stroke milking machine of pairwise action there was obtained a linear dependence (R2=0.9965) between the pressure drop in the milk hose and intensity of milk production. Experimental studies of the value of the pressure drop in the milk hose of the milking machine performed in a cowshed for 200 heads of one of the leading enterprises of the Kirov region confirmed a very close relationship (R 2 = 0.9967) between the current intensity of milk production and the pressure drop in the milk hose when the milk-air mixture moves. Over the entire range of variation in the intensity of lactation, the pressure loss in the descending section varies in the range Δр тр12 = 0.85…1.47 Pa. According to the absolute contribution to the total pressure loss Δр 1-3 = 8293.80…12705.32 Pa, the pressure loss for overcoming gravity force in the ascending section of the milk hose Δр гр = 6611.31…10992.27 Pa has the greatest influence. The results of calculations of the pressure drop in the milk hose performed according to the algorithm proposed in the article, fit into the confidence interval of the experimental measurement of the pressure drop with a 5% significance level. Using the results of the research will allow to predict pressure losses in the milk hose in dependence to the intensity of milk production and take into account the results of calculations when designing milking machines and developing their functioning algorithms for milking high-yield cows.

Incidence of udder cleft dermatitis (UCD) in dairy cows and risk factors for transitions to UCD

Udder cleft dermatitis (UCD) is a common skin condition in Swedish dairy cows, affecting the anterior parts of the udder. The main objective of this study was to investigate incidence rate and duration of UCD in a 1-yr longitudinal study. Other objectives were to investigate risk factors for transitions from being healthy to having mild or severe UCD, and from having mild UCD to having severe UCD, and associations between UCD and clinical mastitis, somatic cell count (SCC) and hock lesions. Seven herds were included in the study and visited 9 times each at 6-wk intervals. At the visits, mild and severe UCD lesions, hock lesions, udder conformation traits, and hygiene scores were registered for each cow milked in the milking parlor. Information on breed, parity, days in milk (DIM), results from test milkings (milk production, SCC, and urea level), and veterinary treatments was also obtained. A UCD case was defined as one or several consecutive observations of UCD. The incidence and duration of UCD were described. Mixed-effect logistic regression models were used to analyze associations between potential risk factors and transitions to any type of UCD. Separate risk factor analyses were performed for transitions to mild and severe UCD. Associations with SCC, mastitis, and hock lesions were also analyzed with mixed-effect logistic regression models. The mean overall incidence of new UCD cases for all visits and herds was 0.5 cases per cow-year at risk. Risk factors associated with a higher risk of a transition to any type of UCD and mild UCD were breed (Swedish Red vs. Swedish Holstein), an indentation or fold at the fore udder attachment, and increasing DIM. In addition, a low milk urea level was associated with a lower risk of transition to any type of and mild UCD. Cows with previous mild UCD and high-yielding cows had increased risk for a transition to severe UCD. Cows that had an observed transition to severe UCD had an increased risk of veterinary-treated clinical mastitis within 6 wk after the UCD observation. No associations were found between UCD and SCC or hock lesions. The median observed duration of a UCD case was 12 wk, but most cases did not have an observed start or end during the study period. The observed duration of cases including severe UCD was longer than for cases involving only mild UCD. The high incidence and often long duration of UCD emphasize the need for preventive measures and treatment strategies.

Improving the physiological and biochemical status of high-yielding cows through complete feeding

Improving the physiological and biochemical status of high-yielding cows through complete feeding

Effectiveness of feed nitrogen use depending on the level of raw protein and the ratio of protein fractions in the rations of cows

Protein nutrition of ruminants as well as other animal species, should be considered as an amino acid nutrition, since not protein as such, but amino acids are the main material for the synthesis of milk proteins, tissues, enzymes, many hormones, neuropeptides and others that play an important role in ensuring the vital functions of the body. Studying the eff ects of diff erent levels of DPR and ratios UPR:DPR with diff erent content of raw protein in rations for nitrogen metabolism, eff ectiveness of feed protein use and dairy productivity of cows is of great scientifi c and practical importance. The purpose of the researches was to determine the optimal levels of undigested protein in rumen (UPR) and digested protein in rumen (DPR) and to determine the possibility of reducing protein consumption in the rations of high-yielding Holstein cows during the early lactation period. It has been found that in rations with 15,7 % crude protein (CP) the optimal ratio was UPR:DPR = 35:65 (UPR – 5,44 %, DPR – 10,3 % DM), which has been confi rmed by the more active formation of free lysine and methionine in the rumen, the yield of microbial protein, higher coeffi cients of digestibility of dry matter, nitrogen, fi ber, higher yield of lysine and methionine in the duodenal chyme, as well as the lowest losses of protein consumed in the process of rumen digestion. Dairy productivity of cows on this ration was at the level of that of cows on rations with 17,7 % CP – 38,7 kg/day when it contains 3,72 % fat and 3,27 % protein. On the ration with the same CP content (15,7 %), but the ratio of UPR:DPR = 50:50 there was a signifi cant decrease in feed consumption (P < 0,01) and the decrease in dairy productivity of cows, which was probably due to the low level of formation of ammonium nitrogen NH3 -N in the rumen.

Evaluation of highly productive cows by selection and genetic parameters

Under the conditions of intensive technologies used in production of livestock products, the main selection feature that characterizes the economic feasibility of dairy farming and breeding value of animals is milk productivity. One of the factors that affects, not only the economy of production, but also the improvement of herds and breeds of cattle, is the use of highly productive cows. Therefore, the aim of our research was to assess the level of development of productive traits in Holstein cows under the conditions of intensive milk production technology, according to selection and genetic parameters. To conduct the study, a group of 1089 first-born cows was formed with the help of the Dairy Comp program and Microsoft Excel. The material for the research was the milk productivity of Holstein cows during the first three lactations. The level of development of selection traits in animals was determined by selection and genetic parameters. It was found that from the sample n = 1089 to the group of highly productive animals (“>10560”) were included 266 cows, and low-productive animals (“<8706”) – 249 first-borns. They had an average milk yield for the first lactation, 11439 kg of milk with a fat content of 3.96 % and 7737 kg of milk and 3.95 %, respectively. There is a difference in milk yield, milk fat and protein between the groups of cows “>10614” and “<8706”, but there is a general tendency towards changes in productivity with age. Based on the data of milk recurrence and the amount of milk fat of high-yielding cows (group “>10614”), it was found that higher values of the coefficient are characteristic of lactations I–III (rw= 0.105; rw= 0.135). As a result of comparative analysis it was found that low-yielding animals (group “<8706”) were characterized by higher recurrence rates for I–II and I–III lactation (rw = 0.345;rw = 0.316;rw = 0.320 and rw = 0.664;rw = 0.646;rw = 0.651, respectively). Higher rates of recurrence of traits of milk productivity are the characteristic of low-yielding cows (group “<8706”), i.e. they had more consistency of traits during different lactations and animals with a high level of productivity did not differ in age constancy. At a high level of milk yield in cows of group “>10614” appeared a negative correlation of low and medium level (r = -0.423). It was also found a negative correlation of low and medium level between milk yield and protein content in milk (r = -0.007… -0.332). At lower milk yields, there is no negative correlation between milk yield and fat content in milk. Thus, the existence of a negative correlation between milk yield and fat content in milk at a high level of animal productivity, and between milk yield and protein content in milk at both high and low levels of cow productivity was proved.

Metabolic Stress in the Transition Period of Dairy Cows: Focusing on the Prepartum Period.

Simple SummaryComplex pathways of metabolic adaptation occur in high-yielding dairy cows around calving. These adaptations require the redirection of nutrients to support the last stages of fetal growth and the commencement of lactation. Failure to adapt to these changes may result in the development of clinical disease in the postpartum period. Therefore, most existing literature is focused on studying the metabolic changes in the postpartum period. However, some of the risk factors associated with postpartum clinical disease can already be found in the prepartum period. This review describes adaptive changes occurring in prepartum high-yielding dairy cows, from drying off (40 to 60 days before parturition) until calving.All modern, high-yielding dairy cows experience a certain degree of reduced insulin sensitivity, negative energy balance, and systemic inflammation during the transition period. Maladaptation to these changes may result in excessive fat mobilization, dysregulation of inflammation, immunosuppression, and, ultimately, metabolic or infectious disease in the postpartum period. Up to half of the clinical diseases in the lifespan of high-yielding dairy cows occur within 3 weeks of calving. Thus, the vast majority of prospective studies on transition dairy cows are focused on the postpartum period. However, predisposition to clinical disease and key (patho)physiological events such as a spontaneous reduction in feed intake, insulin resistance, fat mobilization, and systemic inflammation already occur in the prepartum period. This review focuses on metabolic, adaptive events occurring from drying off until calving in high-yielding cows and discusses determinants that may trigger (mal)adaptation to these events in the late prepartum period.

Effects of heat stress on reproductive efficiency in Holstein dairy cattle in the North African arid region.

This work aims to study the relationship between variations of the Temperature-Humidity Index (THI) and the parameters of reproduction especially the first conception rate (FCR) and to determine the threshold THI value where cows' fertility rate dropped in 12 Holstein dairy herds raised in the arid climatic conditions of Tunisia. THI values were calculated over 22years (1996-2018), and the mean monthly temperature and relative humidity data were obtained from the Meteorological Institute of Tunisia. A total of 20,396 individual records (Insemination and calving dates) were extracted from the Livestock and Pasturing Office (OEP, Tunisia) with regard to the highest THI before breeding, on the breeding day, and after breeding. Statistical analysis was performed using the GLM procedure of SAS software. Results point to the fact that a summer heat stress exists in southeast Tunisia and lasts for 4months starting from June until September with THI values fluctuating between 73±2.38 and 79±3.01 exceeding, therefore, THI threshold of 72. Increased THI from ≤70 to ≥80 units was associated with drops in conception rate (CR) and fertility rate (FR) of 49% and 45% giving a correlation with the THI of (r=-.72, p<.05) and (r=-.74, p<.05), respectively. When cows were inseminated on extremely hot days (THI≥80) preceded by cooler temperatures, pregnancy by service (P/AI) was 7% points higher than for other cows that were exposed to high temperatures before breeding. The average number of insemination was higher (p<.05) from THI≤70 (2.01) compared to THI≥80 (3.41). Cows calving during an absence of heat stress (THI≤70) have the shortest average calving intervals (CI: 420±15.1days). Contrastly, calving in the condition of heat stress (THI≥80) has the longest CI (487±12.8days). For each point increase in the THI value above 67, there is a decrease in the first conception rate by 1.39%. In this particular arid environment, high-yielding Holstein cows' breeding success is strongly affected by heat stress that takes place just before or after breeding.

Features of behavior and productivity of cows and young cattle against the background of the use of feed protein additive Biovitel

Food behavior has a significant influence on all areas of animal use, such as the growth and development of young animals, the quality of milk and meat, and the productivity of cows. The most importance in agricultural ethology is the study of food, group and reproductive behavior. The purpose of the research was to consider the characteristics of behavior and productivity of cows and young animals against the background of the use of feed protein additive Biovitel. It has been found that the time of ruminating, ruminating periods and chewing of feed was higher in high-yielding cows than in low-yielding ones. During the day 17,3 ruminant periods of 28,8 minutes have been registered in highly productive cows, and 15,3 and 35,5 minutes have been registered in cows with average productivity, respectively. The ruminant process in all animals is most active between 21,00 and 24,00 hours, as well as between 2,00 and 5,00 hours, regardless of the season of the year. In high-yielding cows reactions to receiving silage, hay, and straw were somewhat more frequent in comparison with low-yielding ones. It has been found that food activity had a biger influence on the productivity of steers than physical activity. The time spent on sleep has decreased with age and had the same tendency as the growth rate. The time spent on physical activity also has increased with age, but it did not significantly affect the indicators of body weight gain. During all periods of growing the steers that received the feed protein additive Biovitel have been characterized by calm behavior and spent more time eating feed. It has been conducted by the researches and the nature of the results obtained confirm the validity of the use of Biovitel feed additive for the purpose of positive influence on the behavior, productivity of cows, growth and development of young cattle.

Fertility and milk production on commercial dairy farms with customized lactation lengths

Drying-off, calving, and start of lactation are critical transition events for a dairy cow. As a consequence, most animal health issues occur during these periods. By extending the voluntary waiting period for first insemination after calving, calving interval (CInt) can be extended, with possible positive effects for fertility and health. Some cows might be better suited for an extended CInt than others, due to differences in milk yield level, lactation persistency, or health status, which would justify a customized CInt based on individual cow characteristics. This study aims to investigate 13 farms with customized CInt, with respect to calving to first service interval (CFSI), accomplished CInt, services per conception (SC), conception rate at first artificial insemination (CR1AI), peak yield, lactation persistency, 305-d yield, and effective lactation yield. In total, 4,858 complete lactations of Holstein Friesian cows between 2014 and 2019 from the 13 farms were grouped by parity (1 or 2+) and CFSI (CFSI class; CFSI-1 < 84; 84 ≤ CFSI-2 < 140; 140 ≤ CFSI-3 < 196; 196 ≤ CFSI-4 < 252, CFSI-5 ≥ 252 d) or CInt (CInt class; CInt-1 < 364; 364 ≤ CInt-2 < 420; 420 ≤ CInt-3 < 476; 476 ≤ CInt-4 < 532, CInt-5 ≥ 532 d). Cow inseminations, available for 11 out of 13 farms (3,597 complete lactations), were grouped by parity (1 and 2+) and CFSI class or CInt class. The fertility and milk production characteristics were analyzed with generalized and general linear mixed models. The CFSI class was not associated with SC, but extended CInt class was associated with increased SC (CInt-1-5; 1.11-3.70 SC). More than 50% of cows in the CFSI class <84 d ended up in longer than expected CInt (>364 d), showing that these cows were not able to conceive for the desired CInt. More than 50% of cows in CInt classes 3 and higher (CInt ≥ 420 d) had an earlier first insemination before successful insemination (CFSI class 1; <196 d), showing that these extended CInt classes consisted of both cows with an extended waiting period for first insemination and cows that failed to conceive at earlier insemination(s). On most farms, lactation persistency was greatest in CInt class 1 (<364 d), probably related to the low peak yield in this class. When this shortest CInt class was excluded, persistency increased with extended CInt classes on most farms. Although at the majority of farms 305-d yield was greater in CInt ≥ 532 d, effective lactation yield at most farms was greatest in CInt from 364 to 531 d, especially for multiparous cows. Based on the results of this study, a CInt between 364 and 531 days seems most optimal for milk production, when high-yielding cows were selected.

Metabolic profile according to the parity and stage of lactation of high-performance Holstein-Friesian cows.

ObjectiveThe aim of the study was to determine the effect of parity and the stage of lactation on the metabolic profile of cows based on the basic chemical milk components and the blood parameters.MethodsThe study material consisted of high-yielding Holstein-Friesian cows. In total, 473 cows were examined. According to the parity, cows were divided into four groups: primiparous (P), and multiparous in the second (M2), in the third (M3), and in subsequent lactations (M4). The feeding of cows was based on total mixed ration (TMR) ad libitum. Milk and blood samples were collected individually from each cow three times per standard lactation period.ResultsGreater exacerbation of changes in the dynamics of the blood plasma parameters examined was proved for multiparous cows. The highest value of β-hydroxybutyrate acid (0.946 mmol/L) was found for multiparous cows from group M3 at the beginning of lactation. However, it was still in the normal range. The results showed aspartate aminotransferase, and gamma-glutamyl transferase (GGT) activities in dairy cows during lactation had significant variations taking in to account stage of lactation. The highest activity of GGT was found in the group of the oldest cows and measured from 26.36 U/L at the beginning of lactation to 48.75 U/L at the end of the lactation period.ConclusionThe time-related changes in the concentrations of the biochemical parameters described differ markedly among lactating cows, though the housing conditions on the research dairy farm are highly standardised. This indicates that the ability to cope with metabolic stress is mainly affected by the individual predispositions of cows and feed nutrient supply in different stage of lactation. Especially, the feed nutrient supply (in net energy for lactation), which was the best in TMR 1 in comparison TMR 3.

Lupinus angustifolius seed meal supplemented to dairy cow diet improves fatty acid composition in milk and mitigates methane production

Recently, the narrow-leafed, blue lupine (Lupinus angustifolius) seeds, including the Tango variety, have been used as a potential feed of livestock animals. However, there is still a limited knowledge of possible action of the Tango lupine seed meal (LSM) on ruminal fermentation, enteric methane production, milk yield and composition in dairy cattle. Thus, the present study aimed to investigate the effect of LSM supplementation to dairy cows on ruminal enteric methane production, microbial population, ruminal biohydrogenation and fatty acid (FA) proportion in the ruminal fluid and milk. An in vitro trial comprising of control and five experimental groups (supplementation of LSM at 20, 40, 60, 80, and 100 g/kg diet) was conducted to determine an effective dose level for an in vivo experiment. The in vitro trial was followed by an in vivo experiment conducted on 60 high-yielding Polish Holstein Friesian dairy cows assigned into two groups: the control (n = 30) and the experimental LSM group (n = 30; 2 kg LSM/day/cow). Supplementation of LSM decreased methane emission and archaeal abundances in vitro and in vivo and increased ammonia level in vivo. Ruminal total volatile fatty acid concentration and acetate proportion were reduced by LSM supplementation both in vitro and in vivo. Milk yield and its basic composition were not influenced by the LSM. However, the LSM increased the unsaturated FA content and decreased n6 to n3 FA ratio in milk. Supplementation of LSM upregulated the mRNA expressions of FASN and ELOVL5 genes and downregulated the LPL gene expression in milk somatic cells. The daily cost of LSM diet and the cost of 1 kg of milk production were lower compared with the control. It is concluded that LSM supplementation may improve milk quality without affecting milk yield and has the potential to decrease methane production in dairy cows.

THE INDICES OF MILK QUALITY, REPRODUCTION, BLOOD AND RUMEN LIQUID IN HIGHLY PRODUCTIVE COWS IN THE FIRST PERIOD OF LACTATION FOR FEEDING OF MIXED-LIGANDE COMPLEXES OF ZINC, MANGANESE AND COBALT

The article presents data on milk productivity, reproductive function and chemical composition of milk, as well as hematological parameters of blood and rumen liquid in high-yielding Holstein cows of German selection, Ukrainian black-spotted dairy and Ukrainian red-spotted dairy breeds in the first lactation period for feeding them different doses of mixed-ligand complexes of Zinc, Manganese and Cobalt.&#x0D; It is established that the use of mixed-ligand complexes of Zinc, Manganese and Cobalt in the feed mixture in comparison with their sulfates has a positive effect on milk productivity and reproductive function of cows and the chemical composition of their milk, and feed costs decrease with increasing productivity.&#x0D; The use of different forms and levels of Zinc, Manganese and Cobalt in the diets of experimental cows affected protein and carbohydrate-fat metabolism and the best results were obtained when using different levels of these trace elements in the feed due to their mixed-ligand complexes.&#x0D; In the rumen liquid of experimental cows, the pH value increased in the alkaline direction and the difference to the control group was statistically significant. There was also a tendency to increase residual nitrogen compared to control. There was a significant difference in the reduction of ammonia nitrogen in the rumen liquid of cows of experimental groups, which indicates better use and assimilation of crude protein.&#x0D; The best indicators of milk productivity, chemical composition of milk, reproductive function, blood and rumen liquid were obtained when using mixed-ligand complexes of Zinc, Manganese and Cobalt in the feed mixture when the concentration of these trace elements in 1 kg of DM was, mg: Zinc – 60.8; Manganese – 60.8; Cobalt – 0.78; Selenium – 0.3; Copper – 12 and Iodine – 1.1. This concentration of trace elements was achieved due to their mixed-ligandent complexes, copper – its sulfate, iodine – potassium iodide, selenium – selenium suplex.

DIACHRONIC DEVELOPMENT OF LOCAL LINES AND RELATED GROUPS OF BROWN CARPATIAN CATTLE FOR GENERATIONS

DIACHRONIC DEVELOPMENT OF LOCAL LINES AND RELATED GROUPS OF BROWN CARPATIAN CATTLE FOR GENERATIONS

Nutritive value for high-yielding lactating cows of barley silage and hay as a substitute for wheat silage and hay in low-roughage diets

We assessed the effects of replacing wheat silage and hay with barley silage and hay in total mixed rations (TMRs) on: eating behavior, digestibility, and performance of individually fed high-yielding lactating cows. The barley cultivar Ma’anit and the wheat cultivar Omer were grown by dryland farming (210 mm precipitation) in a commercial field with sandy loam soil. The two cultivars were harvested simultaneously for silage or hay at a similar dry matter (DM) content (35.6%). Barley yields exceeded wheat yields by 19% (5.68 vs. 4.79 t DM/ha, P = 0.01). Two-thirds of each crop's DM yield was chopped and transferred for direct ensiling in polyethylene-wrapped bales, and one-third was wilted in the field for 2 weeks and then pressed into hay bales. The chemical composition and in-vitro DM digestibility of the wheat and barley silages and hays were similar. The two experimental TMRs contained either barley silage (280 g/kg DM) and hay (60 g/kg DM) or similar contents of wheat silage and hay, as the sole source of roughage. High-yielding multiparous Israeli Holstein cows were paired into two experimental groups of 21 cows each and fed either wheat- or barley-based TMR ad libitum for 28 days. DM intake of cows fed the wheat TMR was higher than that of the barley TMR-fed cows (28.0 vs. 27.5 kg/day) due to a faster eating rate (137.9 vs. 132.9 g DM/min) and larger meal size. Energy corrected milk production was similar in the two groups (42.4 and 42.8 kg/day), while milk fat yield was higher in barley-fed cows than wheat-fed cows (1.62 vs. 1.57 kg/day). Daily rumination time of the barley-fed cows was longer (577 vs. 537 min/day) and their rumen pH higher during the day and night (P < 0.01) compared to wheat-fed cows. Consequently, in-vivo DM digestibility and neutral detergent fiber digestibility were higher in the barley-fed cows. Our results thus show the benefit of barley as an alternative forage crop to wheat in semiarid regions, and its advantage as a substitute for wheat as silage and hay for high-yielding lactating cows’ TMR.

The effectiveness of the use of feed additive Agolin Ruminant in the rations of lactating cows

An important task for livestock farms is the use of plant feed extracts to improve the effectiveness of dairy production. The development of new alternative drugs based on natural plants allows for the biological protection of animals. Agolin Ruminant is multi-functional feed additive is a mixture of high-quality active ingredients of plant origin, which is designed to optimize consumption and improve feed conversion in the dairy industry. The purpose of the work was to find the increase in the productivity of high-yield cows by using feed additives based on plant extracts on a large number of animals. Production tests have been carried out in the dairy complex of LLC “Tambov-milk” in the Tambov region on Holstein cows with actual productivity at the level of 8500–9000 kg of milk per year. Analysis of cow productivity indicates a positive effect of the introduction of the feed additive Agolin Ruminant in the ration of animals. For example, in the control group of cows for 30 days of lactation the average daily milk yield from 1 cow was 27,44 kg, in the experimental group 28,14 kg, which was more than 700 g or 2,55 %. The introduction of the Agolin Ruminant feed additive into the ration of animals in the experimental group had a positive effect on the fat content in milk, which at the end of the research period was 3,69 % in the control group, and 3,71 % in the experimental group or 0,02 abs.% higher. The protein content in milk in the control group of cows was 3,16 %, and in the experimental group 3,18 % the excess was also equal to 0,02 abs.%. Economic calculations indicate the effectiveness and expediency of using the Agolin Ruminant feed additive in feeding highly productive cows. At the sale price of 1 kg of milk for 29,0 rubles the productivity of cows have been increased by 0,7 kg, and the income from 1 head per day has increased by 17,3 rubles minus the cost of feed additive.

КОНСТРУКТИВНІ ОСОБЛИВОСТІ ДОЗАТОРА КОМБІКОРМУ НА ДОЇЛЬНОМУ РОБОТІ ФІРМИ GEA

High-yielding cows are at risk of carbohydrate poisoning because they get concentrated feed as part of the main diet on the feed table, as well as from the milking system. In order to reduce the risk of overfeeding cows, the ways to improve feed dispenser

Relation between Liver Lipid Content and Plasma Biochemical Indicators in Dairy Cows

Background: The incidence of metabolic disorders in dairy cows has increased as a result of intensive production practices and genetic selection for milk yield. Among such disorders, liver lipidosis is very frequently observed and has significant negative effects on cow health and milk yield. Severe energy supply deficit causes high fat mobilization, resulting in rapid body condition loss and liver lipid infiltration, which cannot always be detected by known blood biochemical indicators. The main objective of the study was to determine possible associations of blood biochemical parameters with liver lipid infiltration severity in high-yield multiparous Holstein cows along prepartum and postpartum periods.Materials, Methods &amp; Results: Fifty-four high-yield Holstein cows from a herd managed in a free-stall system in the northwest region of the state of Rio Grande do Sul, Brazil were evaluated. Cows were divided in two groups according to their physiological status. Group 1 included 19 prepartum cows, with an average milk yield of 44.7 L/d in the previous lactation, and 2.8 average parity, and Group 2 included 35 postpartum cows, with an average milk yield of 46.8 L/d in the previous lactation, and 2.5 average parity. The farm produced 10,000 kg milk per year, containing 3.5% of fat, 3.2% of protein and 4.7% of lactose. Total cholesterol (CH), plasma triglycerides (TGp), beta-hydroxybutyrate (BHB), albumin (ALB), non-esterified free fatty acids (NEFA) levels, and aspartate aminotransferase (AST) and creatine kinase (CK) activities were analyzed in the plasma and liver triglycerides (TGl) levels were determined in liver tissue samples.The SPSS statistical software was used for the statistical analyses. The obtained data were analyzed for normality by the Shapiro-Wilk test and for homoscedasticity by Bartlett test. Data were submitted to analysis of variance, and means were compared by the t-test (PROC TTEST). Pearson correlation test (PROC CORR) was used to compare the results between prepartum and postpartum cows, and between those with and without lipidosis.An overall incidence of 20% severe hepatic lipidosis was determined both in prepartum and postpartum cows. Positive significant correlations were obtained between days in milk (DIM) and AST (r= 0.43; P &lt; 0.01), CH and TGp (r= 0.44; P &lt; 0.01), TGl and AST (r=0.32; P &lt; 0.05), NEFA and AST (r= 0.45; P &lt; 0.01) and CK and AST (r= 0.447; P &lt; 0.01). Negative significant correlations were detected between TGp and DIM (r= -0.45; P &lt; 0.01), and between TGl and TGp (r= -0.30; P &lt; 0.05).Discussion: Prepartum cows showed moderate fat infiltration in the liver, while 25.7% of postpartum cows presented severe lipidosis. AST values increased as lactation progressed, suggesting a greater tendency of liver damage, in early postpartum. The obtained CK values were within the reference range, except for the cows with hepatic lipidosis, indicating that the measured AST activity was originated from the liver and not from the muscle tissues. TGp, NEFA and AST values indicate the degree of fat mobilization and, possibly, liver infiltration, while TGl indicates fat infiltration in the liver. Although negative energy balance (NEB) may trigger lipolysis and some degree of hepatic lipidosis, plasma BHB values did not significantly increase. The obtained results show that the evaluated plasma parameters may be useful to establish guidelines for the identification of changes in the metabolic profile of dairy cows during different production stages, as well as measures for the prevention and control of metabolic disorders.

Відтворна здатність голштинських різновікових корів в умовах промислового комплексу

The article presents studies results on the subject of reproductive capacity indicators of different ages high-yielding Holstein cows in the conditions of an industrial complex for milk production. The study was conducted on the basis of PJSC (Private Joint Stock Company) Agro-Soyuz in the Sinelnikovsky district of the Dnipropetrovsk region (Ukraine). The experimental groups of animals were formed in the following way: group I (n = 35) – first-calving heifers; group II (n = 35) – animals of the second lactation; group III (control), (n = 35) – animals of the third lactation; group IV (n = 35) – cows of the fourth lactation. Certain age dependence of the insemination index has been established. Young first-calving heifers and adult cows of the fourth lactation (groups I and IV) had a relatively better value of this indicator – 4.5 units. At the same time, cows of the second and third lactation (group II; group III – control) were characterized by a sharp decline in reproductive ability, therefore, for one fertilization it was necessary to carry out 5.8 artificial inseminations for them. Based on the level of the insemination index by research groups, it was logical that the calving-to-conception interval for all experimental animals was much lower than the stereotyped value (60–80 days) and averagely amounted to almost 8 months. Infertility in animals of experimental groups was directly determined by the calving-to-conception interval duration and the average value of which was within 165 days. More infertile days were recorded in the dairy complex with group III cows (control) – 195 days. The value of the adaptation index in the experimental groups was unaligned. Cows of the first two lactations (groups I and II) were characterized by this stable value of 7.6 units. After that, during the third lactation (group III – control), it was increased by 2 units – 9.6, and in adult cows of the fourth lactation (group IV), it had a tendency to rapidly decrease to 4.8 units. First-calving heifers (group I) and adult cows (group IV) had the lowest production losses because they had the fewest infertile days. Animals of the third lactation (group III – control) were characterized by the highest production losses – 0.68 calves and 3 166 kg of milk.