Diet optimization for dairy cows to reduce ammonia emissions

Feeding livestock a balanced diet with a differentiated crude protein (CP) content, depending on the lactation phase can reduce nitrogen emissions from livestock excrement and urine. A higher content of non-starch polysaccharides in livestock diets improves feed absorption in the livestock body and, consequently, nitrogen is emitted more from protein present in livestock manure than from urea acid present in livestock urine. The aim of the study is to calculate the ammonia emission reduction potential in Latvia by optimizing the feeding of dairy cows and ensuring life longevity, as well as provide justification for ammonia emission reduction in dairy farms. Calculations made by using the NorFor Model for optimization of dairy cow (Bos primigenius f. taurus) diets revealed that compared with lowyielding cows, a higher CP content diet fed to high-yielding cows at the beginning of lactation increased the amount of nitrogen (N) in their excrement and urine by 90–180 g d-1. Reducing the CP content in the cow diet by an average of 10 g kg-1 dry matter (DM) during mid-lactation resulted in the same trend. Reducing the CP content in the cow diet during late lactation and the dry period by another 20–30 g kg-1 of DM, N emissions from excrement and urine significantly decreased. Increasing the lifespan of dairy cows also means reducing ammonia emissions from the farm. By increasing the number of lactations per cow on dairy farm, it is possible to reduce the number of heifers per cow. The total reduction of ammonia emissions in Latvia was calculated based on a long-term projection of a decrease of 0.1 heifer per dairy cow. Ammonia emissions could be reduced by 0.051 kt by decreasing the number of heifers by 12.54 thou. at the planned increase in the lifespan of dairy cows by 2030.

The Effect of Feeding Management and Culling of Cows on the Lactation Curves and Milk Production of Primiparous Dairy Cows

The study attempted to estimate the lactation curves of primiparous dairy cows in relation to their feeding management. Therefore, the first aim of the study was to determine and compare the lactation curves of primiparous dairy cows using Wood’s model and to estimate the association between the lactation curves and feeding management. The second objective was to investigate the effect of the culling rate on improvement in the milk yield of primiparous dairy herds. The study was conducted on four commercial dairy farms of Polish Holstein–Friesian cows using different feeding systems (TMR—total mixed ration and PMR—partial mixed ration) and management (T1—one TMR throughout lactation; P1—one PMR throughout lactation; T2 and T3—three feed periods such as FRESH, TMR I and TMR II according to days in milk). The data used for the study were obtained from monthly milk performance evaluations of 1662 primiparous cows conducted by the Polish Federation of Cattle Breeding and Dairy Farmers throughout the year 2015. Wood’s lactation model was used to plot curves for milk yield, fat and protein content, lactose content, and milk urea contents. The highest milk yield for the whole lactation and in the peak lactation phase was recorded for cows in herd T1. This herd reached peak lactation on day 105 of milking, with an average milk yield of 42.1 kg, which was about 5 kg more milk than in the other herds. The study showed that the culling of primiparous cows in herd T1 after 30, 60 and 90 days of lactation prevented a significant reduction in milk yield in a 305-day lactation. It also increased average milk production by 1586.9 kg per primiparous dairy cow.

Changes of Plasma Analytes Reflecting Metabolic Adaptation to the Different Stages of the Lactation Cycle in Healthy Multiparous Holstein Dairy Cows Raised in High-Welfare Conditions

Here, we tested the changes occurring in several plasma analytes during different stages of the lactation cycle of high welfare raised multiparous Holstein cows, and provided reference intervals (RI) for plasma analytes concentrations. Eleven high-welfare farms (HWF) located in Northern Italy were selected and their herds used to recruit 361 clinically healthy cows undergoing the dry (from −30 to −10 days from real calving; DFC), the postpartum (from 3 to 7 DFC), the early lactation (from 28 to 45 DFC) and the late lactation phases (from 160 to 305 DFC). Cows affected by subclinical diseases (SCD) were retrospectively excluded, and a subset of 285 cows was selected. Data of plasma analytes underwent ANOVA testing using physiological phases as predictors. The individual effect of each phase was assessed using a pairwise t-test assuming p ≤ 0.05 as a significance limit. A bootstrap approach was used to define the reference interval (RI) for each blood analyte within physiological phases having a pairwise t-test p ≤ 0.05. The concentration of nonesterified fatty acids, albumin, cholesterol, retinol, paraoxonase and tocopherol changed throughout all the physiological phases, whereas the concentration of K, alkaline phosphatase and thiol groups remained stable. Triglycerides, Zn, and ferric ion reducing antioxidant power in the dry phase and BHB, Ca, myeloperoxidase, haptoglobin, reactive oxygen metabolites and advanced oxidation of protein product in postpartum differed compared with other physiological phases. During the dry phase, Packed cell volume, Cl, and urea concentrations were similar to during the postpartum phase. Similarly, Na, γ-glutamyl transferase and β-carotene concentrations were similar to during the early lactation phase; fructosamine and bilirubin concentrations were similar to during the late lactation phase. During the postpartum phase, fructosamine and P concentrations were similar to during the early lactation phase, and the aspartate transaminase concentration was similar to during the late lactation phase. During the early lactation phase, Mg, creatinine, total protein, globulin and ceruloplasmin concentrations were similar to during the postpartum phase, while the urea concentration was similar to during the late lactation phase. All these plasma analytes differed among the other phases. This study identifies physiological trends affecting plasma analytes concentrations during the different stages of the lactation cycle and provides a guideline for the duration and magnitude of their changes when animals are healthy and raised in optimal welfare conditions.

Unraveling the Relationship between Milk Yield and Quality at the Test Day with Rumination Time Recorded by a PLF Technology

The study aimed to estimate the components of rumination time (RT) variability recorded by a neck collar sensor and the relationship between RT and milk composition. Milk test day (TD) and RT data were collected from 691 cows in three farms. Daily RT data of each animal were averaged for 3, 7, and 10 days preceding the TD date (RTD). Variance component analysis of RTD, considering the effects of farm, cow, parity, TD date, and lactation phase, showed that a farm, followed by a cow, had major contributions to the total variability. The RT10 variable best performed on TD milk yield and quality records across models by a multi-model inference approach and was adopted to study its relationship with milk traits, by linear mixed models, through a 3-level stratification: low (LRT10 ≤ 8 h/day), medium (8 h/day < MRT10 ≤ 9 h/day), and high (HRT10 > 9 h/day) RT. Cows with HRT10 had greater milk, fat, protein, casein, and lactose daily yield, and lower fat, protein, casein contents, and fat to protein ratio compared to MRT10 and LRT10. Higher percentages of saturated fatty acid and lower unsaturated and monounsaturated fatty acid were found in HRT10, with respect to LRT10 and MRT10 observations.

Effectiveness of a probiotic based on lactic acid bacteria when changing diets in dairy cows

Relevance. Single-type feeding of dairy cows has a significant advantage over traditional split ration feeding due to the minimal frequency of changes in the composition of the ration and the higher stability of feeding. However, in the process of such a feeding method, it is still necessary to change the diet composition during the seasonal transition from the last year feed to the current year feed. This change leads to significant feed stress for animals, which negatively affects the intensity and nature of cicatricial digestion, and, consequently , productivity. At the same time, at least 100-150 kg of the annual milk yield of a cow is lost. For this reason, the development of a method for eliminating the inevitable cows' stress during the change of feeding seems relevant.Methodology. Scientific and economic experience on dairy cows of the first lactation phase was carried out in accordance with generally accepted methods. The biochemical composition of the blood was studied, observations of the ruminatory processes were carried out, the data were processed by modern methods of variation statistics using the EXCEL program.Results. As a result, it was found that during the transition from one diet composition to another, it is advisable to introduce a probiotic based on lactic acid bacteria into dairy cows diet. The use of a probiotic can be considered as a preventive measure for digestive disorders caused by changes in the composition of the diet. The use of a probiotic helps to stabilize the ruminal processes in cows, which is reflected in an increase in the frequency of cicatricial contractions. Probiotic effect on the intestinal microbial community, increases the immune status of the body by increasing the level of protein, gamma-globulin fractions in its composition, as well as increasing the reserve alkalinity index.

Relation between swine weight and morphometric measurements

Objective was to define a mathematical model that better explain the relationship of the animals weight depending not only on the animals age but also on the animals morphometric measurements. 40 piglets, half Duroc-Large White blood, were used, 20 males and 20 females, from 3 to 35 days of age (lactation phase) initially weighing 1.518 ± 0.121 kg and from 36 to 66 days of age (calving phase) with a body weight of 7.010 ± 0.704 kg. The animals were weighed weekly on a digital balance. The relationship of animal weight, age and morphometric measurements of male and female piglets were performed using regression models: existing, linear and power. The models were evaluated according to nine criterialinear model was the most adequate to explain the weight of male pigs, while for female pigs was the power. The age of the pig, the shank and palette length, as well as the circumference of the shank jointly explain the weight of the male piglets. The weight of females is explained jointly by age, body length, thorax and hip circumference.

Impact of SNPs in ACACA, SCD1, and DGAT1 Genes on Fatty Acid Profile in Bovine Milk with Regard to Lactation Phases

Milk fat is a dietary source of fatty acids (FA), which can be health promoting or can increase risks of some diseases. FA profile composition depends on many factors, among them gene polymorphism. This study analyzed the relation between polymorphism of acetyl-CoA carboxylase α (ACACA), stearoyl-CoA desaturase 1 (SCD1), diacylglycerol acyltransferase 1 (DGAT1) genes with FA profile in milk from Polish Holstein-Friesian cattle and determined changes of FA percentage during lactation with regard to polymorphism. Milk samples were collected twice: during the first phase of lactation (<90 Days in milk; DIM) and at the end of lactation (>210 DIM). During the first milk collection, blood samples were taken to analyze three chosen single nucleotide polymorphisms (SNPs): AJ312201.1g.1488C > G SNP in ACACA gene, A293V SNP in SCD1 gene, and K232A SNP in DGAT1 gene. Increased concentration of FA that are less beneficial for human health and have lower concentration of healthy FA in homozygotes: GG in ACACA, VV in SCD1, and KK in DGAT1 were observed, as well as a strong influence of the analyzed genes on FA with 18C atoms was also found. Moreover, it was demonstrated that lactation phase significantly affected FA percentage in milk depending on the phenotype. These results may contribute their part to knowledge toward obtaining more beneficial milk composition.

Performance and maternal-offspring behavior of ewes fed protected fat from palm oil

This study aimed to evaluate the performance and maternal-offspring behavior of ewes fed protected fat from palm oil. Forty multiparous ewes with an average age of three years were divided into two treatments, with or without protected fat supplementation (in concentrate). Every 15 days and at the time of lambing, weighing and body condition evaluation of sheep were performed, while lambs were evaluated at birth until weaning. Duration of post-weaning anestrus was obtained through the manifestation of estrus, detected by a vasectomized male. Data were submitted to analysis of variance. No difference was observed between supplementations for body weight, body condition score, and average daily gain during the gestation phase. Ewes fed protected fat had a superiority regarding the body score during the lactation phase. Lambs from ewes supplemented with protected fat were weaned faster, and ewes presented an early estrus. No difference was observed between treatments for maternal-offspring behavior. The use of fat during lactation showed improvement in productive (body condition score) and reproductive (shorter anestrus period) parameters. It also reduces the weaning age of lambs and does not alter maternal-offspring behavior.

Impact of supplementation with different protein sources on the parasitological profile of ovine matrices and development of lambs

The aim was to evaluate the impact of supplementation with different protein sources from agro-industrial production on the parasitological profile of ovine matrices and the development of their offspring. The protein sources used were: soybean bran, cotton pie, babassu pie, and coconut pie. A total of 60 ovine matrices were used, with confirmed pregnancy and supplemented in the final third of gestation at 0.5% of live weight in pastures of deferred Marandu grass. The evaluations occurred from the final third of gestation and in the lactation phase until weaning. The data collected in the matrices were: counting of eggs per gram of feces (EPG) and identification of infective larvae (Faecal test), evaluation of the degree of anemia by the FAMACHA© method, body weight (kg), and body condition score (BCS). In the lambs, the biometric measurements were taken from the 30 days of life until weaning. In Faecal test, the prevalence was 98% of Haemonchus spp. There was no effect of the protein sources for EPG (3476.0) and FAMACHA©. However, in the mats supplemented with coconut pie were observed the lowest body weights (36.9 kg) and lower BCS (2.7). Babassu, coconut and cotton cakes, and soybean meal used as a protein source in the supplementation of ovine matrices kept in deferred pastures of Marandu grass at the 0.5% level of live weight maintain the production indexes consistent with the physiology stage of the matrices even with a high endo-parasitic load.