Level Of Milk Production Research Articles

Evaluation of rations of high-yielding cows with different energy levels

The materials of the publication reflect the results of scientific research conducted on the Simmental breed dairy cows in the conditions of the “Pchany-Denkovych” farm in the Stryi district of the Lviv region. The study is based on optimizing the normalized energy nutrition of dairy cows with a milk yield of 6000 kg or more per lactation. The main objective of the research was to study the impact of different levels of energy nutrition of cows by lactation phase and its effect on productivity, hematological indicators, the level of individual rumen metabolites, digestibility of essential nutrients, nitrogen balance, and live weight dynamics. Three groups of eight cows each were selected for research. The rations of the experimental animals provided for the inclusion of a protein-fat concentrate in the compound feed at the rate of 5–10 % by nutrition. The main ration consisted of bulk fodder, cereal-bean hay, hay, silage, and balanced compound feed, which were fed from the feed table in the form of a mixture prepared in a feed mixer–the farm practices year-round uniform feeding of cows with a walking yard. The deficiency of mineral substances in the diet was replenished due to iodized salt, monocalcium phosphate, and polysalts of trace elements. Feeding and housing conditions for all experimental animals during the comparison period lasting 15 days were the same and differed in the reference period in terms of nutrient availability in percentages. The analysis of the obtained results showed that increasing the energy supply of cows had a positive effect on milk productivity. In the first period of lactation, the highest yield was obtained from cows of the third group, which indicates that the experimental animals are approaching the maximum possible potential productivity. This trend persists both in the second and third periods. The increased level of energy nutrition due to the use of protein-fat concentrate had a positive effect on the increase in the live weight of cows. During the analysis of the obtained indicators of the rumen content, a probable increase in the number of amylo- and cellulolytic bacteria was revealed - the quantitative advantage (second and third group) compared to the control is 1.52–2.33 and 1.67–2.54 million/ml. A similar pattern is observed in the number of proteolytic bacteria, which contributed to the increase in the enzymatic activity of the microflora. Regarding the digestibility of the primary nutrients of the feed, their growing trend was established in the second and third groups, which confirms the results of the balanced experiment. Thus, animals of the second group are characterized by the highest digestibility and assimilation of nitrogen. Its positive balance was (+7.1) compared to the third and (+3.0) to the first, in which the nitrogen balance was negative. The use of nitrogen for milk in these groups was the highest: from consumed – 31.7 % and from digested – 48.5 %. Thus, the conducted studies provide a reason to recommend that the farm use a protein-fat concentrate of 5% of the diet's total nutrition in the feeding of dairy cows. Its use will ensure an increase in the level of milk productivity and will make it possible to optimize the energy nutrition of cows during the calving period and mid-lactation.

8 Impact of Increasing Level of Milk Production on Cow and Calf Performance in the Nebraska Sandhills

Abstract Selection for increased milk production across the United States has resulted in variable cow and calf productivity responses. The calf growth response variability may be due to the relationship between calf milk and forage intake, which nursing and grazing behavior may help explain. The objectives of this study were to determine the impact of increasing level of milk production on cow body weight (BW), body condition score (BCS), reproductive performance, calf growth, nursing, and grazing behaviors in the Nebraska Sandhills. In a 2-yr study, data were collected on 118 mature crossbred cow-calf pairs from March- and May-calving herds. On approximately 30, 60, 90, 120, and 210 d postpartum, individual cow 24-h milk yield was estimated through weigh-suckle-weigh techniques. Cow BW and BCS were collected 14 d prior to calving, weekly from d 30 through breeding, and at weaning. Calf BW was recorded at each milking. Calf nursing and grazing behaviors were determined during 3-wk periods at EARLY (65.4 ± 10.0 d) and LATE (162 ± 22.3 d) lactation using high frequency (1 hz) global positioning system (GPS) data collected with neck collars. Milk area under the curve values were calculated to determine total milk production during lactation for each cow and all response variables were analyzed using linear regression analysis. Cow BW, BW change, and reproductive performance were not (P > 0.12) associated with total milk production, except for a tendency (P = 0.09) for lower BW at breeding with increased milk production. At weaning, cow BCS was negatively associated (P = 0.02) with increasing milk production but was not associated at any other physiological stage. Calf percent of time spent grazing was not affected (P = 0.33) by increasing dam milk production. However, percent of time nursing exhibited a tendency (P = 0.10) to decrease with increasing dam milk production. Pre-weaning calf BW was positively associated (P < 0.01) with increased milk production at each weigh date. A positive association of calf average daily gain (ADG) with increasing dam milk production was observed (P < 0.04) from birth to age 120 d with only a tendency (P = 0.09) for a positive association observed from age 120 d to weaning. However, steer ADG in the finishing phase was not associated (P = 0.63) with level of dam milk production. In this study and environmental conditions, increasing milk production had a positive increase in calf growth during the pre-weaning phase without any negative impact reproduction.

ANATOMICAL AND TOPOGRAPHIC FEATURES OF BRANCHING OF MAMMARY GLAND ARTERIES IN AN ANGLO-NUBIAN GOAT BREED

Milk productivity is one of the most important economically useful indicators for which selection is carried out. The level of milk productivity depends on heredity, physiological state, conditions of feeding and use of animals. All other things being equal, the level of milk productivity depends on the breed of the animal. To date, many studies have been conducted on vascular vascularization of the mammary gland in ruminants, but few of them concerned the application of anatomical features of the course and branching of vessels in possible surgical and obstetric-gynecological interventions. In connection with the above about the relevance of breast research, we set a goal to study the anatomical and topographic features of the branching of the arteries of the mammary gland in a goat, and use the Anglo –Nubian breed as a model. The study was conducted on the basis of the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. The dated material was delivered from the farm of the Moscow region of the Russian Federation "Gzhelskoe podvorye". The age of the studied animals was 1 year and older. The age was determined from the words of the chief veterinarian of the farm "Gzhel farmstead", as well as according to the bonus cards and according to the dental formula of the methodology of Professor I.I. Kalugin, a total of 15 individuals were studied. During the study, such methods as: fine anatomical dissection, vascularization, morphometry, photographing were used. According to the results of the study, species and breed anatomical and topographic features of the branching of the arteries of the mammary gland in the goat of the Anglo-Nubian breed were established. The main sources of breast vascularization in the Anglo-Nubian goat breed have been identified. These studies can be used by veterinary specialists in farms and large livestock complexes for breeding goats during surgical and obstetricgynecological manipulations.

Diffusion of precision livestock farming technologies in dairy cattle farms

The rising global demand for animal products and the growing public concerns about the environment and animal welfare require dairy farms to improve their efficiency and apply more sustainable farming systems. Precision Livestock Farming (PLF) could represent a valuable support in addressing these challenges. In recent years, dairy farms have been modernising and introducing new sensors and automatic systems for managing the herd. However, the diffusion of new technologies in Italian dairy farms is still limited and farmers are reluctant to invest in precision systems. The aim of the study was to investigate the presence of PLF tools in Italian dairy farms, the motivations, benefits and limits of technological investments from the farmers’ point of view and the factors affecting the diffusion of technology. From November 2020 to June 2021, an online questionnaire was distributed and 52 responses were obtained. About 79% of the farms were located in Lombardy. The more represented milking system was the conventional milking parlour (73%), followed by automatic milking (19%). The average age of respondents was quite low: 35% of them was less than 40 years old and more than 50% was between 40 and 60. Statistical analyses were performed to evaluate the effects of different factors on the presence of technology at farm. The age of the farmer, the milk production level and the presence of an automatic milking system influenced the technological level of the farm. Precision systems that provide information on animal activity for the management of reproduction and on milk yield and flow are the most popular and are considered among the most useful. Management of reproduction and milk production are the areas where farmers appear to show interest for future investments as well. Younger farmers appear to have implemented more PLF systems than older ones, and they show a propensity to invest in latest generation precision tools. Farmers seem to have a growing interest in PLF, but some limits have been identified: the investment costs, followed by the lack of time to check information from sensor systems and the difficulty in data interpretation. As PLF technologies can play an important role in the development of sustainable, animal-friendly and efficient livestock production, further improvements and efforts are necessary to increase the propensity to PLF of dairy farmers. Results can be useful in the Italian context but also in other countries where dairy farming is rapidly intensifying but PLF is encountering resistance.

Association of PRLR, IGF1, and LEP genes polymorphism with milk production and litter size in Egyptian Zaraibi goat

Studying variation in genes responsible for physiological characters is important to enhance goat productive and reproductive efficiency. This study aimed to detect specific nucleotide polymorphisms in prolactin receptor (PRLR), insulin-like growth factor (IGF1), and leptin (LEP) genes and their correlation with milk production (MP) and litter size (LS) traits in Zaraibi goat. PCR-SSCP products of different patterns of each gene were sequenced and aligned to reveal two mutations (T > C) and (G > A) in 3′UTR of PRLR gene and registered on NCBI with accession numbers OM418863 for TT and OM418864 for CT, while (G > A) variation was registered as OM418861 for GG and OM418862 for AG in exon 10. TT, CT, AG, and GG genotypes were distributed in the studied animals with frequencies 0.43, 0.57, 0.65, and 0.35, respectively. While alleles C, T, A, and G frequencies were 0.28, 0.72, 0.32, and 0.68, respectively. CT and AG genotypes associated significantly (P < 0.05) with higher MP and LS, respectively. By studying the haplotypes of PRLR, C-A and T-A were associated with the highest and the lowest level of MP, respectively. For LS, T-A and C-G showed significant correlation with the highest and the lowest rate, respectively. Regarding IGF1 gene, two polymorphisms were detected; T74C at exon 4 which registered on NCBI as OM418860, and combined mutations as ins. G470, A531G, and T534C (PP genotype) at 5′ flanking region that registered as OM418859. For LEP, only one polymorphism was found in intron 2 (G281A) which submitted to NCBI as OM418855. All detected polymorphisms have shown to be involved in regulating the MP or LS as reproductive traits in goat.

Clinical and diagnostic characteristics of the development of hepatocardial syndrome in black and white cows in the early lactation period.

It is known that during the early postpartum and lactation periods in dairy cows, metabolic disorders develop, that is, ketosis, which can lead to secondary damage to internal organs. Therefore, it is important to address the issues of changing the lactating cows' clinical, laboratory, and physiological parameters regarding the development of hepatocardial syndrome. This study aimed to provide clinical and diagnostic justification for developing hepatocardial syndrome in highly productive dairy cows. The study was conducted on 20 black and white cows in the early postpartum period (7-10 days after birth), with a milk production level of >4500 kg of milk during the previous lactation period, a positive result in the formol colloid sedimentary test, the presence of deafness and splitting of heart sounds, changes in the size, or increased pain sensitivity of the percussion field of the liver. Clinically healthy dairy cows in the early postpartum period were used as controls (n = 24). Clinical, electrocardiographic, echocardiographic, and biochemical parameters were also evaluated. Dairy cows with hepatocardial syndrome developed arterial hypertension and sinus tachycardia, which led to a significant decrease in PQ and QT intervals at ECG. A significant increase in the diastolic size of the interventricular septum, systolic size of the free wall of the left ventricle, and diastolic and systolic sizes of the left ventricle and a significant decrease in the shortening fraction of the left ventricular myocardium were observed in the cows due to the development of hepatocardial syndrome. The affected cows demonstrated a significant increase in serum activity of gamma-glutamyl transferase, alanine aminotransferase, lactate dehydrogenase, creatine phosphokinase, alkaline phosphatase, troponin, malondialdehyde, diene conjugates, and ceruloplasmin and a decrease in glucose concentration. In addition, they demonstrated decreased activity of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase. Hepatocardial syndrome in dairy cows occurs due to ketosis, characterized by arterial hypertension, sinus tachycardia, a moderate decrease in myocardial contractility, oxidative stress, and cytolysis of cardiomyocytes and hepatocytes. Therefore, the control and prevention of the development of hepatocardial syndrome will make it possible to maintain the productive health and longevity of dairy cows.

Rumen-protected zinc-methionine dietary inclusion alters dairy cow performances, and oxidative and inflammatory status under long-term environmental heat stress.

Dairy cows are susceptible to heat stress due to the levels of milk production and feed intake. Dietary supplemental amino acids, particularly rate-limiting amino acids, for example, methionine (Met), may alleviate the potential negative consequences. Zinc (Zn) is beneficial to the immune system and mammary gland development during heat stress. We investigated the impact of a source of a rumen-protected Zn-Met complex (Loprotin, Kaesler Nutrition GmbH, Cuxhaven, Germany) in high-producing Holstein cows during a long-term environmental heat stress period. A total of 62 multiparous lactating Holstein cows were allocated in a completely randomized design to two dietary treatments, namely, basal diet without (control) and basal diet with the supplemental Zn-Met complex (RPZM) at 0.131% of diet DM. Cows in the RPZM group had higher energy-corrected milk (46.71 vs. 52.85 ± 1.72 kg/d for control and RPZM groups, respectively) as well as milk fat and protein concentration (27.28 vs. 32.80 ± 1.82 and 30.13 vs. 31.03 ± 0.25 g/kg for control and RPZM groups, respectively). The Zn-Met complex supplemented cows had lower haptoglobin and IL-1B concentration than the control (267 vs. 240 ± 10.53 mcg/mL and 76.8 vs. 60.0 ± 3.4 ng/L for control and RPZM groups, respectively). RPZM supplementation resulted in better oxidative status, indicated by higher total antioxidant status and lower malondialdehyde concentrations (0.62 vs. 0.68 ± 0.02 mmol/L and 2.01 vs. 1.76 ± 0.15 nmol/L for control and RPZM groups, respectively). Overall, the results from this study showed that RPZM dietary inclusion could maintain milk production and milk composition of animals during periods of heat stress. Enhanced performance of animals upon Zn-Met complex supplementation could be partly due to improved oxidative and immune status.

Longevity, productive and reproductive traits of cows of Black-and-White breed

The intensification of dairy cattle breeding and the crossbreeding of many breeds of cattle with Holstein breed has led to the premature culling of cows from the herd and currently in Russia the longevity of dairy cows does not exceed 2,6–3,6 calving, i. e. the animals do not live up to the period of maximum milk productivity and payback for the cost of rearing heifers. When studying the issue of productive longevity of dairy cows, the study of its association with the level of milk productivity and reproductive traits is of particular interest. Dairy productivity and reproductive function in cows are interrelated and are the main factors determining the profi tability of the dairy cattle industry. The purpose of the research was to analyze the longevity, productive and reproductive traits of cows of Black-and-White breed in the Vologda region. It was found as a result of the research that the longest duration of economic use (3,39 lactations and 1569 days) and the lifetime productivity of milk the basic fat content (27 104 kg) had animals with a blood content of Holstein breed of 26 to 49 %. Along with this, the largest number of calves (4,13 heads) was obtained from animals with this genotype during the period of economic use. Analysis of the infl uence of lifetime productivity of dams on the productive longevity and reproductive traits of their daughters showed that a longer period of economic use (985 days), the largest number of completed lactation (2,32) and higher lifetime productivity (21 574 kg) was noted in daughters of cows with a lifetime milk yield of 35 000–44 999 kg. Animals that optimally combine the parameters of productive, reproductive traits and longevity have been identified, and the economic efficiency of their use has been determined in the paper.

Perspective: School Meal Programs Require Higher Vitamin D Fortification Levels in Milk Products and Plant-Based Alternatives—Evidence from the National Health and Nutrition Examination Surveys (NHANES 2001–2018)

Poor vitamin D status impairs bone growth and immune defense in school-aged children and adolescents, particularly in minorities. Vitamin D insufficiency/deficiency increases the risk of acute viral respiratory infection, underscoring the need for adequate vitamin D intakes during school sessions when viral exposure may be greatest. We studied available vitamin D-related survey data and published findings based on NHANES (2001-2018) to assess the dependency of vitamin D status {25-hydroxyvitamin D [25(OH)D]; in nmol/L} on vitamin D intake (μg/d) in elementary school-aged children (4-8 y), middle school children (9-13 y), and high school adolescents (14-18 y). We sought evidence supporting the need for school programs to facilitate vitamin D adequacy. Usual vitamin D intakes from food and beverages by children/adolescents (NHANES 2015-2018) examined at the 50th percentile intake by race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic) showed all age groups consumed less than half of the Estimated Average Requirement (EAR) for vitamin D (10μg/d), independent of race/ethnicity. NHANES (2001-2010) analyses show evidence of lower vitamin D status in school-aged children that is linked to lower intakes of fortified milk varying over race/ethnicity and age. Adolescents had lower vitamin D status and milk intake than younger children. A total of 22-44% of vitamin D intakes occurred away from home, with larger percentages of total intakes at breakfast and lunch, at times consistent with school meals. Ever-present inadequate vitamin D intakes with a large percentage consumed away from home together with well-established benefits to growth, bone, and immune defense from enriched vitamin D-fortified milk in school intervention trials provide strong justification to require enriched vitamin D-fortified foods in school meals. An easy to implement plan for improving vitamin D intakes is possible through the FDA's amendment allowing higher vitamin D fortification levels of dairy and plant-based milk alternatives that could increase vitamin D intakes beyond the EAR with just 2 daily servings.

Assessment of 5-hydroxymethylfurfural levels in carbonated soft drinks and milk products on the markets in the Kumasi Metropolis of Ghana

Processing of food products makes them palatable, edible, provides options to consumers and prolong their life spans. Irrespective of these benefits, some of these processes have also shown to increase the build-up of potential toxic metabolites, for example, 5-hydroxymethylfurfural (5-HMF). 5-HMF production results from caramelization and/or Maillard reactions involving carbohydrates and some proteins. Its levels are thus used as an indicator of thermal treatment and suitability of storage conditions. At significantly, higher levels in products, they have been shown to elicit deleterious effects on consumers. The current study was carried out to monitor the levels of 5-HMF in carbonated soft drinks (CSDs) and milk products (MPs) on the market as their consumptions have increased in recent years. Using a validated spectrophotometric method, it was shown that 5-HMF levels in MPs ranged between 1.165 ± 0.007 g/L and 2.638 ± 0.010 g/L and that in the CSDs was between 0.0294 ± 0.00018 g/l and 0.0845 ± 0.00049 g/L. However, the estimated 5-HMF exposure levels from the consumption of these products were shown to be within internationally acceptable limits of 0.005 g/L – 0.15 g/L. The 5-HMF levels observed however demonstrated differences in the two types of products analysed, differences in different brands of similar products, batch-to-batch variations for same brands, and differences in products from different origins. These observations may be indicative of inconsistencies in applicable industrial processing systems. The outcome of this study calls for the need to appraise existing processing systems, to assure reproducible quality products.

RESEARCH OF THE QUALITATIVE COMPOSITION OF MILK OF COWS OF SIMMENTAL BREED

Modern dairy breeds of cattle have high milk yields. This is especially true of breeds created using Holstein breed [14]. At the same time, scientists have repeatedly stated that the use of Holstein breeders deteriorates the quality characteristics of milk productivity. Therefore, the influence of conditional blood by Holstein breed significantly affects productivity. However, researchers emphasize that the breed as a genetic factor has a significant impact on milk productivity. This explains the influence of the biochemical composition of milk on the profitability of the dairy industry.&#x0D; Dairy breeds that have been created in Ukraine over the past twenty years are characterized by a sufficient level of milk yield and quality indicators. The level of milk yield of animals is more than 7.0 thousand kg of milk with fat and protein content in milk above 3.8% and 3.2%, respectively. Some breeds, which are created on the basis of domestic combined breeds are characterized by a sufficient level of milk components. Their fat content in milk is more than 4.0%, and protein – more than 3.4%. During lactation, the content of milk components changes.&#x0D; The aim of our work was to investigate some indicators of the biochemical composition of milk of Simmental cows.&#x0D; Materials and methods. The research was conducted on Simmental cows kept in the Mykhailivka PZ of the Lebedyn District of the Sumy Region (n = 46) and the Urozhay SFG of the Romensky District of the Sumy Region (n = 30).&#x0D; For sampling of milk used counter – indicator IU-1. The milk sample was stored in a plastic container (25 ml) during the day at a temperature of +3C0, using the preservative chrompic. The content of fat and protein in milk was determined in the laboratory of Sumy National Agrarian University on the equipment Ultrasonic milk analyzer Master Classic manufacturer Milkotester Ltd (Bulgaria).&#x0D; The results of the research were processed by the methods of mathematical statistics using the "Statistica-6.1" package in the Windows environment on a PC.&#x0D; The animals fully meet the requirements of the breed standard for both the first (standard 2700 kg) and the third lactation (3500 kg).&#x0D; In terms of milk yield, Simmental cows met the requirements of the breed standard for both the first and second lactations.&#x0D; Biochemical analysis of milk was carried out to determine the level of such indicators as fat, protein, lactose, dry matter and dry nonfat milk residue. According to all the studied features, the first-born were inferior to adult animals. A statistically significant difference was found between the fat and protein content of milk in favor of adult animals. As a result, it can be argued that there is a significant difference in the amount of dry matter and dry skim milk residue between animals of different ages. Adult animals met the breed standard in terms of both fat and protein content, the first-born animals were slightly lower than the standard in terms of protein content.&#x0D; There are relationships of different directions and magnitudes between the contents of individual components. Statistically significant correlation coefficients were found between the content of: fat and protein; fat and dry matter; protein and dry matter; protein and skimmed milk powder.&#x0D; Conclusions. As a result of research, it was found that both first-born and adult Simmental cows are characterized by a sufficient level of milk productivity with high quality milk. In all respects, they met the requirements regulated by the breed standard, with the exception of the first in terms of protein content. There is a significant positive correlation between individual indicators (0.75 ± 0.03–0.96 ± 0.01).

ORGANIZATIONAL AND ECONOMIC PRINCIPLES OF THE FUNCTIONING OF THE MILK MARKET UNDER THE CONDITIONS OF UKRAINE’S MEMBERSHIP IN THE EU

The article is devoted to the assessment of the organizational and economic basis of the functioning of the milk market in the conditions of Ukraine’s membership in the EU. The main reasons for the reduction of the number of cows both in agricultural enterprises and households have been established. It has been proven that in the current conditions, the subjects of entrepreneurial activity – producers of dairy products do not have the opportunity to carry out even a simple reproduction of the cow population at the expense of their own sources. Today, the system of tribal service, which existed earlier in Ukraine and made it possible to conduct tribal affairs at the proper level, does not work. Therefore, further increase in productivity and improvement of animal reproduction indicators are extremely problematic due to the lack of a modern breeding system in animal husbandry. It has been established that most dairy farms have passed the stage of modernization of the material and technical base, which ensures the production of high-quality milk. In our opinion, subjects of entrepreneurial activity in the field of agro business – milk producers can compete with agricultural producers from EU countries in the presence of effective state support for dairy farming and the observance of partnership relations with processing enterprises and trade. The introduction of innovative technologies in dairy farming, especially agricultural enterprises, ensures a high level of milk productivity of cows, which corresponds to the corresponding values ​​of the average annual milk yield of most countries of the European Union. The analysis of benefits and risks for dairy farming from Ukraine’s participation in the EU makes it possible to determine the directions of the national policy in terms of reducing risks, neutralizing negative consequences and accelerating the realization of benefits from the liberalization of trade regimes: promotion of exports with the aim of expanding foreign sales markets for Ukrainian exporters of dairy products; stimulation of domestic demand for milk and milk products; increasing the competitiveness of domestic producers of milk and milk products on the basis of improving the quality and safety of products due to the implementation of international quality standards; ensuring the competitiveness of domestic producers on domestic and foreign markets in accordance with effective state support measures for mixed agricultural enterprises – milk producers with the aim of attracting private investments for their development; avoiding negative impacts on personal peasant farms on the basis of the development of service and sales cooperation, the formation of the appropriate infrastructure, financial support for the process of transformation of commercial personal peasant farms into small agribusiness subjects – milk producers; promotion of rural development, active use of the benefits of the “green box” by the World Trade Organization.

Fermented Rubber Seed Kernel with Yeast in the Diets of Tropical Lactating Dairy Cows: Effects on Feed Intake, Hematology, Microbial Protein Synthesis, Milk Yield and Milk Composition.

Simple SummaryRubber seed kernels do not contain sufficient levels of crude protein to serve as a primary source of crude protein in ruminant diets. Yeast has been used to improve the nutritional value of feedstuffs, particularly their protein content, and to diminish their anti-nutritional components. Our earlier studies demonstrated that rubber seed kernels that had undergone yeast fermentation had enhanced levels of crude protein, decreased fiber content, and could be provided to dairy heifers as a source of protein. The current findings showed that the addition of yeast-fermented rubber seed kernels had no negative effects on the hematology, milk production, milk composition, or feed intake. Hence, yeast-fermented rubber seed kernels could be used as a source of protein in the diets of lactating dairy cows.The objective of the present study was to analyze the effects of yeast-fermented rubber seed kernels (YERSEK) on the feed intake, hematology, microbial protein synthesis, milk yield, and milk composition in dairy cows. Six crossbred Holstein Friesian (HF) × Thai lactating dairy cows with 110 ± 10 days in milk were randomly assigned to three different amounts of YERSEK at 0%, 10%, and 20% in a concentrate mixture using a 3 × 3 repeated Latin square design. Cows were fed with concentrate diets at a concentrate-to-milk yield ratio of 1:1.5, with rice straw fed ad libitum. The inclusion of YERSEK did not adversely affect feed intake, nutrient intake, or digestibility (p > 0.05), whereas ether extract intake and digestibility linearly increased in dairy cows receiving YERSEK (p < 0.01). Increasing YERSEK levels did not adversely affect blood urea nitrogen (BUN) levels, hematological parameters, or microbial protein synthesis (p > 0.05). Supplementation of YERSEK did not influence milk production, lactose, or protein levels (p > 0.05). However, milk fat and total solids decreased linearly (p < 0.05) with the addition of YERSEK. In conclusion, in a concentrate diet, YERSEK could be used as a protein source without negative effects on feed intake, digestibility, hematology, microbial protein synthesis, or milk yield. However, it reduced the milk fat and total solids of tropical lactating dairy cows.

Residual feed intake in peripartal dairy cows is associated with differences in milk fat yield, ruminal bacteria, biopolymer hydrolyzing enzymes, and circulating biomarkers of immunometabolism

Residual feed intake (RFI) measures feed efficiency independent of milk production level, and is typically calculated using data past peak lactation. In the current study, we retrospectively classified multiparous Holstein cows (n = 320) from 5 of our published studies into most feed-efficient (M-eff) or least feed-efficient (L-eff) groups using performance data collected during the peripartal period. Objectives were to assess differences in profiles of plasma biomarkers of immunometabolism, relative abundance of key ruminal bacteria, and activities of digestive enzymes in ruminal digesta between M-eff and L-eff cows. Individual data from cows with ad libitum access to a total mixed ration from d -28 to d +28 relative to calving were used. A linear regression model including dry matter intake (DMI), energy-corrected milk (ECM), changes in body weight (BW), and metabolic BW was used to classify cows based on RFI divergence into L-eff (n = 158) and M-eff (n = 162). Plasma collected from the coccygeal vessel at various times around parturition (L-eff = 60 cows; M-eff = 47 cows) was used for analyses of 30 biomarkers of immunometabolism. Ruminal digesta collected via esophageal tube (L-eff = 19 cows; M-eff = 29 cows) was used for DNA extraction and assessment of relative abundance (%) of 17 major bacteria using real-time PCR, as well as activity of cellulase, amylase, xylanase, and protease. The UNIVARIATE procedure of SAS 9.4 (SAS Institute Inc.) was used for analyses of RFI coefficients. The MIXED procedure of SAS was used for repeated measures analysis of performance, milk yield and composition, plasma immunometabolic biomarkers, ruminal bacteria, and enzyme activities. The M-eff cows consumed less DMI during the peripartal period compared with L-eff cows. In the larger cohort of cows, despite greater overall BW for M-eff cows especially in the prepartum (788 vs. 764 kg), no difference in body condition score was detected due to RFI or the interaction of RFI × time. Milk fat content (4.14 vs. 3.75 ± 0.06%) and milk fat yield (1.75 vs. 1.62 ± 0.04 kg) were greater in M-eff cows. Although cumulative ECM yield did not differ due to RFI (1,138 vs. 1,091 ± 21 kg), an RFI × time interaction due to greater ECM yield was found in M-eff cows. Among plasma biomarkers studied, concentrations of nonesterified fatty acids, β-hydroxybutyrate, bilirubin, ceruloplasmin, haptoglobin, myeloperoxidase, and reactive oxygen metabolites were overall greater, and glucose, paraoxonase, and IL-6 were lower in M-eff compared with L-eff cows. Among bacteria studied, abundance of Ruminobacter amylophilus and Prevotella ruminicola were more than 2-fold greater in M-eff cows. Despite lower ruminal activity of amylase in M-eff cows in the prepartum, regardless of RFI, we observed a marked linear increase after calving in amylase, cellulase, and xylanase activities. Protease activity did not differ due to RFI, time, or RFI × time. Despite greater concentrations of biomarkers reflective of negative energy balance and inflammation, higher feed efficiency measured as RFI in peripartal dairy cows might be associated with shifts in ruminal bacteria and amylase enzyme activity. Further studies could help address such factors, including the roles of the liver and the mammary gland.

Peripheral blood mononuclear cell mitochondrial enzyme activity is associated with parity and lactation performance in early lactation Holstein dairy cows

Mitochondria are central to metabolism and are the primary energy producers for all biosynthesis, including lactation. The objectives of this study were to determine if high- and low-producing dairy cows exhibit differences in peripheral blood mononuclear cell mitochondrial enzyme activities of citrate synthase, complex I, complex IV, and complex V during early lactation and, thus, to determine whether those differences were related to differences in lactation performance in the dairy cow. Fifty-six Holstein cows were assigned to 1 of 4 groups: (1) primiparous high, (2) primiparous low, (3) multiparous high, or (4) multiparous low. Primiparous and multiparous cows were analyzed separately. Then, cows were divided into high or low production groups for each production parameter [peak milk, average milk, energy-corrected milk (ECM), fat-corrected milk (FCM), milk lactose, milk fat, milk protein, total solids (TS), solids-not-fat, feed efficiency, and somatic cell count (SCC)]. For all data analysis, production parameters are expressed as yields (kg/d) and SCC (103 cells/mL). High and low production groups were defined by their respective mean production parameters for the 56 cows, with below average cows defined as low and above average cows defined as high. Whole blood samples were collected at one time point, approximately 70 d in milk at 0800 h, and processed for crude mitochondrial extracts from peripheral blood mononuclear cells to determine the activity rates of mitochondrial enzymes. Milk samples were collected 9 times (3 d, 3 times per d) during the week of blood collection and analyzed for major components (fat, protein, lactose, TS, and SCC). Multiparous cows had lower citrate synthase activity than primiparous cows across all production parameters. High-producing cows had greater complex I activity for peak milk, milk yield, ECM, FCM, milk fat, TS, and feed efficiency, and greater complex V activity for ECM, FCM, milk lactose, milk fat, and TS across parities. These findings imply that the most influential respiratory chain enzymes on the level of milk production are those responsible for electron transport chain initialization and ATP production.

Assessment of the Relations for Determining the Profitability of Dairy Farms, A Premise of Their Economic Sustainability

The profitability of dairy farms is a broadly addressed issue in research, for different farming systems and even more so now, when it comes to the issue of sustainability in different agricultural fields. The present study presents an evaluation of the relations used for the determination of profitability of various categories of dairy farms, in terms of size, geographical area, and total milk production. In order to analyze the associated influence exerted on the level of profitability by the selected technical and economic indicators, regression functions were applied. The TableCurve program was used to determine the ideal equation that describes the data entered in a two- or three-dimensional representation. The research results showed that the size of farms and the level and value of milk production are directly correlated with profitability, and the unit cost is inversely correlated with it.

Influence of feeding level on the formation of milk productivity of dry cows

The materials of the publication demonstrate the results of scientific research conducted on Simmental cattle in the farm “Pchany-Denkovych” Stryy district of the Lviv region. The research is based on optimizing the normalized feeding of cows during the start-up period. The diets of experimental animals include low, medium, and high levels of energy nutrition according to detailed standards. The study was conducted on three groups of Simmental cows with eight heads each. The analysis of the obtained results showed that the different levels of energy nutrition of experimental animals did not significantly affect the hematological parameters; their level was within physiological norms for healthy animals. Estimating the intensity of metabolic processes in the body of dry cows was carried out based on the contents of the scar. There was a probable increase in the number of amylo- and cellulolytic bacteria, the number of which prevailed (the second and third groups) in comparison with the control by 1.42–2.32 and 2.32–2.53 million/ml. A similar pattern was observed for the number of proteolytic bacteria. The increase in these populations of microorganisms contributed to their enzymatic activity, which led to a probable increase in the number of LVH, which are precursors of milk fat. According to the indicators of live weight gain during the dry season, animals of the second and third groups had an advantage. Physicochemical parameters of milk were also better in these groups of cows; the higher the level of nutrition, the higher the fat, protein content in milk. A similar analogy is observed for the dynamics of the live weight of calves, which is directly proportional to the level of feeding cows during the dry season. For four months, the calves of the experimental groups had higher growth energy (6.7–10.5 % compared to the control). The control over the level of milk productivity of cows after calving was carried out according to control milk yields, which showed that the hopes for lactation in the experimental groups were 7.2–8.0 % higher than in the control group. This is because the animals of the experimental groups, due to the higher level of feeding according to detailed standards in the dry season, deposited more nutrients in the body and thus provided a higher level of milk productivity. Therefore, the conducted research gives grounds to recommend the farm to use high and medium levels of energy nutrition for cows during the dry season.

Vulnerability assessments in dairy cattle farms based on individual sensitivity to heat stress.

Climate change (CC) is expected to increase temperatures and the frequency of extreme weather events, which renewed interest in heat stress (HS) effects on dairy cattle farms. Resilience is a key concept that should be considered to better understand the dairy farms exposure to HS and to combat CC-related risks. Thus, this study aimed to investigate the aspects of HS vulnerability for Tunisian dairy cattle farming systems. Historical milk test-day records from official milk recording were merged with temperature and humidity data provided by public weather stations. Firstly, different models relying in two heat load indices were applied for HS exposure assessment. Secondly, broken line models were used to estimate HS thresholds, milk losses, and rates of decline of milk production associated with temperature-humidity index (THI) across parities. Thirdly, individual cow responses to HS estimated using random regression model were considered as key measures of dairy farming system sensitivity assessment to HS. Dairy farms are annually exposed for 5months to high THI values above 72 in Tunisia. The tipping points, at which milk yield started to decline over parities with 3-day average THI, ranged between 65 and 67. The largest milk decline per unit of THI above threshold values was 0.135 ± 0.01kg for multiparous cows. The milk losses estimated due to HS in the Holstein breed during the summer period (June to August) ranged between 110 and 142kg/cow in north and south, respectively. A high HS sensitivity was proved especially in dairy farms characterized by large herd size and high milk production level. Hence, providing knowledge of dairy farms vulnerability to HS may provide the basis for developing strategies to reduce HS effects and plan for CC adaptation.

High body condition score combined with a reduced lambing to ram introduction interval improves the short-term ovarian response of milking Lacaune ewes to the male effect

The male effect is an effective natural technique to induce off-season ovulation and ultimately mating or artificial insemination in small ruminants. It constitutes an alternative to hormonal treatments in conventional breeding systems and, to shift and organise the yearly production cycle, is currently the only solution complying with European organic standards. However, its associated performances are still heterogeneous, both in terms of the global response and the extent of reproductive synchronisation of the females, due to complex interactions with environmental factors that limit its use on commercial farms. This study was carried out on a French organic farm under commercial conditions to investigate, in the field and across five consecutive years, the main parameters affecting the early ovarian response to a ram effect on Lacaune dairy ewes. While the within-year binary logistic regressions yielded contrasting results, the cross-year mixed-effect binary logistic regression models clearly showed that parameters associated with the nutritional state of the animals have a profound influence on the ovarian response of the ewes. Indeed, the probabilities of a spontaneous resumption of ovarian activity before the ram effect and of an early ovarian response to the ram effect were positively associated with the body condition score, total milk production and the age of the animals, while being negatively associated with the milk production level at the 3rd milk recording. The probabilities of a spontaneous resumption of ovarian activity before the ram effect were positively associated with the interval between lambing and the introduction of the rams. Altogether, these results indicate that the ovarian performances in response to a male effect follow a bell-curve pattern with optimal performances depending upon a complex combination between photoperiodic and nutritional cues. Regarding these latter, this study highlights the major contribution of body reserves and energy balance dynamics.

Estimation of dairy productivity of Kholmogorsky cows with allel variants of prolactin and somatotropin genes

The interrelation of allelic variants of prolactin and somatotropin genes with indicators of milk productivity of cows of the Kholmogory breed for the 1st and 3rd lactation was studied. The highest milk yield (5040 and 5836 kg) amount of milk fat (194,5 and 224,1 kg) and milk protein (163,8 and 189,1 kg) are observed in the group with the PRL AA genotype in first-calf heifers as well as in full-age cows. In terms of the mass fraction of fat and protein in milk the 3rd lactation cows with the PRL genotype BB significantly exceeded the other groups of animals by 0,13-0,15% (P &lt;0,001) and 0,05% (P &lt;0,05), respectively. According to the somatotropin gene, the highest level of milk productivity was revealed in animals with the GH LL genotype, with a significant advantage over full-age cows GH VL and GH VV in milk yield by 280 kg (P &lt;0,001) and 509 kg (P &lt;0,001), by the amount of milk fat by 9,1 kg (P &lt;0,001) and 18,5 kg (P &lt;0,01), by the amount of milk protein per 7,9 kg (P &lt;0,01) and 14,8 kg (P &lt;0,01). The highest butterfat and protein-milk content belongs to animals with the GH VV genotype that are 3,90% and 3,26%. The obtained data indicated a higher level of milk productivity in cows with the PRL AA and GH LL genotypes, but the best fat and milk content was noted in cows with the B allele of the PRL gene and the V allele of the GH gene in their genotype.