Lactation Yield Research Articles

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.

Ethyl Lactate Production from the Catalytic Depolymerisation of Post-consumer Poly(lactic acid)

Bioplastics such as poly(lactic acid) (PLA), which are derived from renewable sources, promoted as biodegradable and implemented for numerous functions, offer a promising alternative to the enduring synthetic plastics abundant in society. However, the degradation of PLA is slow under natural environmental conditions. A chemical recycling route is thus required to couple mitigation of plastic persistence repercussions with circular economy adherence. In the present work, the production of ethyl lactate by the catalysed transesterification of post-consumer PLA was investigated. The catalyst employed was a propylendiamine Zn(II) complex. The PLA samples investigated consisted of a phone case, an infant’s toy, a film, a cup and 3D printing material. Degradation reactions were studied at 50 °C and 90 °C and the concentrations measured at two different time intervals, 1 h and 3 h. The results revealed that greater activity of the catalyst was observed at 50 °C for two PLA samples (cup, 3D print). PLA film achieved the greatest lactate yield (71%) of all samples after 3 h at 50 °C. It is concluded that the propylenediamine Zn(II) catalyst can be used to produce green solvent ethyl lactate at mild temperatures from post-consumer PLA, even in the presence of unknown additives.

ВЛИЯНИЕ УПИТАННОСТИ КОРОВ ПЕРЕД ОТЕЛОМ НА КАЧЕСТВО МОЛОЗИВА ПЕРВОГО УДОЯ

The aim of the research is improving the quality of dairy breed colostrum by regulating their fatness before the calv-ing. Research was carried out in 2018-2019 in the conditions of dairy breed complexes of SEC «Yuzhny», &#x0D; LLC «Zvezda», LLC «Radna» of the Samara region on cows of: Bestuzhevskaya; Black-and-White of domestic selection; Holstein, imported from Germany; Ayrshire from Finland. The chemical composition, physiological prop-erties and content of immunoglobulins were studied in colostrum of the first lactation yield, 30-60 minutes after the calving. It has been found that if the fatness decreases below 3.6-4.0 points, the fat in the colostrum of Bestu-zhevskaya breed decreases by 0.5-1.2%, Back-and-White – by 0.5-0.9%, Holstein – by 0.7-1.6%, Ayrshire – by 0.5-1.4%, the protein, respectively by 1.9-5.5; 0.7-1.5; 0.5-1.3; 1.1-4.3%. If the fatness increases above 4.0 points, fat and protein in the colostrum also decreases. Colostrum of all milk breeds studied, showed that its acidity meets the phiziological requirements, with the exception of Holstein breed with fatness below 3.0 points (44.5ºT). When the fatness decreased below the optimum, the content of immunoglobulins in the colostrum lowed too, respectively, in breeds by 8.1-24.5; 5.3-12.9; 6.1-16.6; 6.7-22.7%, with an increase of 4.2; 1.9; 7.4; 4.9%. Thus, the reduction or increase of breed fatness, compared to the optimal level (3.6-4.0 points), leads to a decrease of main components in colostrum including density, acidity, and the most important point a decrease in the content of immunoglobulins, which perform a protective function newborn calves.

МОЛОЧНАЯ ПРОДУКТИВНОСТЬ КОРОВ ГОЛШТИНСКОЙ ПОРОДЫ В ЮЖНО-ЛЕСОСТЕПНОЙ ЗОНЕ ПРЕДУРАЛЬЯ

The purpose of the research is to increase the efficiency of Holstein cows of different breeds in the southern forest-steppe zone of the Pre-Urals. Due to the lack of highly productive dairy cattle, Holstein cows are imported to Russia from different countries. Imported animals have different adaptability, productivity, terms of economic use, and prof-itability. For the first time on the stud farm «Alekseevsky» state owned located in Ufa district Republic of Bashkorto-stan a comparative evaluation of body conformation, lactation yield and physical and chemical indicators of Hol-stein milk of different selections in terms of adaptive technology. Cows of Hungarian selection have a stronger con-formation, proportion, length, well-developed body, as evidenced by boniness and lengthiness. Hungarian cows dominate over German and Finnish cows in body weight by 11.2 and 22.5 kg (P&lt;0.05). These features led to the superiority of animals of Hungarian origin in milk productivity with the same adaptive technology of keeping and feeding. During the third lactation, milk yield of Hungarian origin was 736.6 kg (P&lt;0.05) more than that of German-bred, and 766.7 kg than that of Finnish cows. Hungarian average milk yield of Hungarian breed for three lactation periods was bigger 521.5 kg (P&lt;0.05) and 625.1 kg (P&lt;0.05), respectively. German breed had the highest fat con-tent (3.3%), and Hungarian cows the highest protein content (3.3%). There were no significant differences between the animals of the studied groups in terms of productive longevity (3.26-3.38 lactations). Cows of Hungarian origin for all the time of use had basic fat content and protein more by 5.5 and 6.0%, compared with their herdmate, which increases revenue by 9.9 and 10.8 thousand rubles more than from cows of German and Finnish selection.

Colostrum composition and immunoglobulin G content in dairy and dual-purpose cattle breeds.

Immunoglobulins (Ig) are essential components in the colostrum of bovine species that enable passive immunization of newborn calves. Concentrations of fat and protein are greater in colostrum compared with mature milk and represent a vital source of energy and nutrients. Colostral IgG was shown to vary between individual dairy cows, but comparative data on different breeds and performance levels are scarce. The objective of the present field study was to investigate the contents of total IgG, fat, protein, and lactose in colostrum in different Swiss and German dairy and dual-purpose breeds. We collected colostrum samples of 458 cows of 13 different breeds (dairy breeds: Brown Swiss, Swiss and German Holstein Friesian, and New Zealand Holstein; dual-purpose breeds: German Fleckvieh, Holstein Friesian × Montbéliarde, Montbéliarde, Murnau-Werdenfels, Original Braunvieh, Pinzgauer, Rhetic Gray, and Simmental; and beef-type crossbred: Charolais × Holstein Friesian). Colostrum samples were obtained between 5 and 900 min after calving and analyzed for total IgG, fat protein, and lactose contents. Immunoglobulin G concentrations varied between 12.7 and 204.0 mg/mL. No effect of breeding purpose (i.e., dairy or dual-purpose) nor of previous lactation yield on IgG content was observed. However, milking of cows for the first time later than 12 h after parturition resulted in lower colostrum IgG concentrations compared with colostrum harvest within 9 h after calving (P < 0.05). Multiparous cows had a higher colostral IgG concentration than primiparous cows (P < 0.0001). Overall, concentrations of IgG and other constituents in colostrum varied widely in the different cattle breeds. High-yielding dairy cows did not have poorer colostrum quality compared with lower-yielding animals or beef and dual-purpose breeds, which suggests an individually different transfer of circulating IgG into colostrum.

Heat load increases the risk of clinical mastitis in dairy cattle

The study was aimed at assessing heat load-related risk of clinical mastitis (CM) in dairy cows. Records of CM for the years 2014 and 2015 were obtained from a large conventional dairy farm milking about 1,200 Holstein cows in central Italy. A case of CM was defined by the presence of clinical signs and veterinary confirmation. Quarter milk samples were collected and bacteriological investigated for each CM. Etiological agents were identified and classified as environmental or contagious pathogens. Hourly weather data from the nearest weather station were used to calculate heat load index (HLI). Upper and lower thresholds of HLI, at which the animal accumulates or dissipates heat, were settled and used to measure heat load balance through the accumulated heat load (AHL) model. Zero and positive values of AHL indicate periods of thermo-neutral and heat accumulation, respectively. Each case of CM was associated with HLI-AHL values recorded 5 d before the event. The risk of CM was evaluated using a case-crossover design. A conditional logistic regression model was used to calculate the odds ratio and 95% confidence intervals of CM recorded in thermo-neutral (AHL = 0) or heat load (AHL > 0) days, pooled or stratified for pathogen type (environmental or contagious). Classes of AHL as low (<6.5), medium (6.6-34.9), and high (>35) were included in the model. Other variables included in the model were milk yield as liters (<20, 20-30, and >30), days in milk (<60, 60-150, and >150), and parity (1, 2-3, and >3). A total of 1,086 CM cases were identified from 677 cows. Escherichia coli, Streptococcus spp., and Streptococcus uberis were the environmental pathogens isolated with the highest frequency; Staphylococcus aureus prevailed within contagious species. The analysis of pooled data indicated a significant effect of heat load on the occurrence of CM in the contagious pathogen stratum. Higher milk yield, middle and late stage of lactation, and older parity increased the risk of CM under heat load conditions. However, the association between pathogen type and these factors was not clear because the model provided significant odds ratios within all pathogen categories. The present study provided the first evidence of an association between HLI and CM in dairy cattle and suggested the ability of the AHL model to assess the risk of mastitis associated with heat load.

Yield of milk and milk constituents of lactating dairy cows fed on paddy straw plus non-forage fibre sources based complete rations having varying levels of neutral detergent fibre

A study of six months duration was conducted to assess the yield of milk and milk constituents of lactating dairy cows fed on paddy straw plus non-forage fibre sources based complete rations containing different levels of NDF, in two phases, viz., early and mid lactation. Three isonitrogenous and isocaloric complete rations, T 1 , T 2 and T 3 with 25, 30 and 35 per cent NDF, respectively were formulated as per the recommendations of ICAR-NIANP (2013). Paddy straw was the sole source of roughage NDF, in all the three rations. Eighteen dairy cows yielding approximately 10 kg of milk per day were divided into three groups of six each and allotted to the three experimental rations. The average daily milk yield of cows fed on the experimental rations, T 1 , T 2 and T 3 , in phases I and II were similar (P 0.05). All these yields were highest in cows of T 3 , followed by T 2 and T 1 , in descending order, with the values in the three dietary treatments being significantly different (P<0.05), among themselves in phase II as well as the total experiment. A thorough evaluation of the results obtained in the present study, reveal that the animals in all the three dietary treatments performed well, with the complete rations T 3 with 35 per cent NDF and T 2 with 30 per cent NDF, showing better performance than T 1 with 25 per cent NDF. Among T 2 and T 3 which were more or less comparable in milk yield, the cows fed on diet T 3 remained in peak milk yield for longer period than those in T 2 . The cows fed on diet T 3 had a significantly higher (P<0.05) FCM, fat and protein yield in early, mid and total lactation than those fed on the diet T 2 , indicating that T 3 was better than T 2 . These results suggest that complete rations with 25 to 35 per cent NDF, containing paddy straw as the sole source of roughage NDF, can be recommended for use among early and mid lactation dairy cows, with 35 per cent being the ideal NDF level.

The impact of the installation of an automatic milking system on female fertility traits in Holstein-Friesian cows

The objective of the study was to compare 305-day lactation milk yield in first and second lactations and selected fertility traits (number of services per conception, service period (days between first and last insemination), age at insemination and calving, gestation length, calving to conception period, calving interval period) in 2620 conventionally and automatically milked Polish Holstein-Friesian cows during the first two reproductive cycles. The study was conducted in 16 dairy herds that had been transitioned from a conventional milking system (CMS) to an automatic milking system (AMS) in the years 2010–2013. Sources of variation for the traits measured, including the milking system, were tested by multifactorial analysis of variance and the generalized linear model using a Poisson and negative binomial models and log link function using SAS. After switching from a conventional to an automatic milking system, milk yield increased by 1078.35 and 1182.24 kg in first- and second-lactation cows, respectively. In terms of fertility traits, the change in the milking system had a significant effect only on service period in the first reproductive cycle (CMS–22 days; AMS–15 days) and the number of inseminations needed for pregnancy (CMS–2.01; AMS–1.79) and on age at calving (CMS–1244; AMS–1226 days) in the second reproductive cycle. It must be emphasized that more favourable fertility traits (except for the calving to conception period in the second reproductive cycle) were observed in the group of automatically compared to conventionally milked cows. The interaction between herd and milking system was significant for most of the examined traits.

Dietary galactosyl and mannosyl carbohydrates: In-vitro assessment of prebiotic effects

The prebiotic activities of hydrolyzed guar gum (GMOS, <1 kDa; GMPS, 1–10 kDa), manno-oligosaccharide (MOS, <1 kDa), and galacto-oligosaccharide (GOS, <1 kDa) were evaluated by in vitro fermentation. The tested carbohydrates showed selective prebiotic effects on bacterial growth, short-chain fatty acid (SCFA)-production, and substrate consumption. GOS and GMOS markedly promoted the growth of bifidobacteria and Clostridium butyricum, respectively, whereas MOS showed the strongest butyrogenic effect. Moreover, SCFA production in the hydrolyzed guar gum groups was closely related to the varied molecular weight (Mw) of the hydrolysate. During in vitro fermentation with human fecal inocula, GMOS gave the highest yields of lactate, propionate, and butyrate after 48 h fermentation. Combined application of MOS and C. butyricum increased the abundance of Clostridiaceae_1. Overall, our results indicate that galactosyl and mannosyl carbohydrates have individualized prebiotic effects which are associated with their chemical structures including their glycoside composition and Mw.

Animal Model Versus Polynomial Legendre Test-Day In Dairy Cattle

Abstract The aim of the study was to compare the classical animal model (based on total milk for 305 days) with the Test-Day model (using monthly records of milk yield from Official Records of Performances). The data set derived from a total 175 animals (cows with records, parents of these animals and the descendants) from two Romanian breeds (Romanian Black Spotted and Montbeliarde), the phenotypic and the pedigree information arisen from National Research Development Institute for Animal Biology and Nutrition (IBNA-Balotesti). The selection criteria to be included in the analysis for each cow was to have at least 3 test-days and the days in milk between 200 and 330 for the Test-Day model and the total amount of the 305- day lactation yield for classical Animal Model respectively. Both models use B.L.U.P methodology and for that reason all the estimates were adjusted for fixed effects and all the breeding values and the solution for fixed effects were estimated simultaneous. For the animal model the fixed effects used was the breed and the year of performing and for the Test-Day model was an extra one, the test day effect. The correlation calculated between test days was very high (over 90%) for consecutive tests, and was getting lower when the days between tests was higher (under 40%). Also, in terms of heritability the values were in normal limits throughout lactation, except at the beginning and end of lactation period where these values were a little bit higher. The comparison of the ranking of breeding values with Spearman rank correlation shows that in 80% of the cases the ranking was similar for both models. As the ranking correlations shows, it is certain that the two models are very similar when they are used for genetic evaluation. But, in conclusion, we can say that for a better lactation curve estimation it is recommending to use test-day model for dairy cattle.

Influence of the age at the first insemination and live weight on milk productivity of cows

The materials of the long-term (2008–2018) research into the reproductive function of cattle of the black-and-white breed of Baikal type in Irkutsk region are presented. The influence of the age at the first insemination and live weight on cows’ milk productivity, lifelong productivity and productive longevity was studied. The experiment was conducted on the basis of materials from the breeder-farm for breeding cattle of Baikal type on the groups of cows of different ages: up to 14–20 months and older. Cows inseminated at 16 months (7917 kg) had the best milk yield in the first lactation. The largest milk yield was obtained from inseminated cows with live weight of 401-410 kg. Milk production of these heifers was 7902 kg in the first lactation, 8792 kg – in the second and 8710 kg – in the third. It was revealed that age of cows and their live weight at the first successful insemination had a positive effect on the lifelong productivity and productive longevity of cows. Cows whose age at the first successful insemination was 15 or 16 months had a longer duration of productive use (productive life span of animals was 2561–2558 days, respectively). The highest lifelong productivity (34379–34585 kg) was obtained from the cows of this group. The economic efficiency of lifelong milk production was determined depending on the age of the first insemination. The highest lifelong milk productivity was obtained from cows, which were first inseminated at the age of 15–16 months. The largest revenue from sales of additional products was also received from the cows of this group (366,058–370,480 roubles per head). The results obtained allow to develop effective methods for increasing reproductive capacity of cattle.

Continuous Conversion of Glucose into Methyl Lactate over the Sn-Beta Zeolite: Catalytic Performance and Activity Insight

In this study, we developed an efficient technology for the continuous conversion of glucose into methyl lactate over the Sn-Beta zeolite with a trickle bed reactor. The catalyst exhibited a high yield of 59.7% for lactic acid in water, and the total yield of methyl lactate and xylitol reached 59.8% (37.3% for methyl lactate) in methanol. The continuous evaluation of Sn-Beta demonstrated a maximum yield of 45.0% for methyl lactate along with 99% conversion of glucose in methanol, and the catalyst was continuously operated for over 434 h at 165 °C. The changes in Sn coordination and fouling stand as the dominant reason for the activity loss of Sn-Beta. Compared with the rapid decline of activity in water, reaction in methanol exhibited much less carbon deposition, structural changes, and Sn leaching after a long-term operation. The promising result indicated the potential application of Sn-Beta as an industrial catalyst for biomass utilization.

Genome-wide association studies of lactation yields of milk, fat, protein and somatic cell score in New Zealand dairy goats

BackgroundIdentifying associations between genetic markers and traits of economic importance will provide practical benefits for the dairy goat industry, enabling genomic prediction of the breeding value of individuals, and facilitating discovery of the underlying genes and mutations. Genome-wide association studies were implemented to detect genetic regions that are significantly associated with effects on lactation yields of milk (MY), fat (FY), protein (PY) and somatic cell score (SCS) in New Zealand dairy goats.MethodsA total of 4,840 goats were genotyped with the Caprine 50 K SNP chip (Illumina Inc., San Diego, CA). After quality filtering, 3,732 animals and 41,989 SNPs were analysed assuming an additive linear model. Four GWAS models were performed, a single-SNP additive linear model and three multi-SNP BayesC models. For the single-SNP GWAS, SNPs were fitted individually as fixed covariates, while the BayesC models fit all SNPs simultaneously as random effects. A cluster of significant SNPs were used to define a haplotype block whose alleles were fitted as covariates in a Bayesian model. The corresponding diplotypes of the haplotype block were then fit as class variables in another Bayesian model.ResultsAcross all four traits, a total of 43 genome-wide significant SNPs were detected from the SNP GWAS. At a genome-wide significance level, the single-SNP analysis identified a cluster of variants on chromosome 19 associated with MY, FY, PY, and another cluster on chromosome 29 associated with SCS. Significant SNPs mapped in introns of candidate genes (45%), in intergenic regions (36%), were 0–5 kb upstream or downstream of the closest gene (14%) or were synonymous substitutions (5%). The most significant genomic window was located on chromosome 19 explaining up to 9.6% of the phenotypic variation for MY, 8.1% for FY, 9.1% for PY and 1% for SCS.ConclusionsThe quantitative trait loci for yield traits on chromosome 19 confirms reported findings in other dairy goat populations. There is benefit to be gained from using these results for genomic selection to improve milk production in New Zealand dairy goats.

Factors Affecting Lactation Performance of Deoni Cattle

The research was conducted on 78 lactation records of 78 Deoni cows over three years to analyze the effect of non-genetic factors on lactation performance traits. Data of lactation records were analyzed to determine the effect of age, parity, a period of calving and season of calving on lactation traits, viz., lactation milk yield (LMY), peak milk yield (PMY), lactation length (LL) and persistency of lactation. The findings revealed that age group and parity had a significant (p ≤0.05) effect on lactation milk yield, but not the period of calving and season of calving. Further, only the parity had a significant (P≤0.05) effect on peak milk yield of Deoni cattle but not the age group, period of calving, and season of calving. The other two traits, namely lactation length, and persistence was not influenced significantly by any the non-genetic factors evaluated in Deoni cattle.

ESTIMATION OF HOLSTEIN BREED BULLS BY DAIRY PRODUCTIVITY OF THEIR DAUGHTERS

The scientific community has shown that the genetic improvement of dairy cattle depends on many genotypic factors, including paternal ancestry and lineage. With this in mind, the purpose of our research was to evaluate the Holstein bulls of black-and-white and red-and-white suits of different lines for the milk productivity of their daughters.&#x0D; The research was carried out on the basis of primary breeding records of 10 breeding herds of Ukrainian Black-and-White Dairy breed, 3 – Ukrainian Red-and-White Dairy breed and one – Ukrainian Red Dairy breed, which are subordinated to NAAS. Cows of the studied breeds has divided into groups according to lineage and paternal origin.&#x0D; Studies have revealed a significant differentiation of milk yield of cows of the first and highest lactation not only of one breed, but also of linear affiliation and paternal origin. It was found that the yield of the first lactation in cows of the Ukrainian Black-and-White Dairy breed varied from 3211 kg (Damir 7100354042) to 7884 kg (Dzhokus 113080315) of milk. Noteworthy are the daughters of Dzhokus 113080315, from which 9143 kg of milk were obtained for higher lactation, Polyarsten 342347941 and Manteno 344222859 – 8248 kg and 8290 kg of milk, respectively. The significant influence of paternal origin on the yield of Ukrainian Black-and-White Dairy breed cows of the first and higher lactation (31.0%; P &gt; 0.999) and 37.3% has been proved; P &gt; 0.999). The influence of genealogical formation on the milk productivity of cows was significant and amounted to 10.8% for the first lactation, higher – 10.2%. Some of the first-born Ukrainian Black-and-White Dairy breed has characterized by high milk productivity, which steadily increased until the third and higher lactation.&#x0D; The yield of cows of the Ukrainian Red-and-White Dairy breed of the first lactation varied from 5414 kg (Dialog 2009) to 6689 kg (Larets 6177), testifying to better homogeneity of herds in terms of milk productivity compared to the Ukrainian Black-and-White dairy breed. The highest yield of the third and highest lactation – 7626 kg, had cows-daughters of the bull Roman 660886883 Starbuck line 352790. The variability of milking cows of Ukrainian Red-and-White Dairy breed of the first and highest lactation by 25.0% and 15.2%, respectively, was due to the influence of the father offspring and to a lesser extent – belonging to the line.&#x0D; A very high (6517–8013 kg) realization potential of milking cows of the Ukrainian Red Dairy breed was established, but it also depended on the paternal origin and linear affiliation. The highest yield of the first lactation were shown by the daughters of the bull Belisar 365235897, Dzhorin 114414759 and Tumpi 112367468, who produced 8013 kg, 7323 kg and 7170 kg of milk, respectively. In cows of this breed it was found that yield increased with increasing serial number of lactation, with the third and higher lactation cows produced more than 8000 kg of milk per lactation, and the daughters of bull Dzhorin 114414759 – more than 9000 kg. The influence of the bull on the milk productivity of the first-born cows of the Ukrainian Red Dairy breed (16.7%; P &gt; 0.999) is almost three times higher than this linear affiliation. Significant phenotypic variability of milk productivity of cows of different breeds of half-sisters by the father is established. The advantage of the daughters of the bull Belisar 365235897 of the Ukrainian Red Dairy breed on milking of the first lactation over the representatives of the Ukrainian Red-and-White Dairy breed was 1932 kg (p &lt; 0.001). The difference in milk yield of the first lactation of the half-sisters by the father, the bull Konbeo 579810507 was 1007 kg (p &lt; 0.01), and Roman 660886883 – 717 kg.&#x0D; Thus, a significant phenotypic variability of milk productivity of cows of different breeds of half-sisters by father was established. At the same time, regardless of the breeder, the cows of the Ukrainian Red Dairy breed were characterized by higher milk yield of the first lactation in comparison with the Ukrainian Red-and-White Dairy breed.

Chemical Degradation of End-of-Life Poly(lactic acid) into Methyl Lactate by a Zn(II) Complex.

The catalyzed methanolysis of end-of-life poly(lactic acid) (PLA) products by an ethylenediamine Zn(II) complex to form biodegradable methyl lactate was studied experimentally at 70, 90, and 110 °C. The PLA samples consisted of typical consumer waste materials, including a cup, a toy, and a three-dimensional (3D) printing material. High selectivities and yields (>94%) were possible depending on temperature and reaction time. Additionally, and to develop a predictive kinetic model, kinetic parameters (pre-exponential factor and activation energies) of the PLA transesterification reaction were first obtained from virgin PLA. These parameters were subsequently used to estimate the conversion of PLA, selectivity, and yield of methyl lactate after 1 and 4 h of the reaction, and the results were compared with the experimental values of the end-of-life PLA. Despite the presence of unknown additives in the PLA waste material and uncontrolled particle size, the model was able to predict the overall conversion, selectivity, and yield to an average deviation of 5, 7, and 12%, respectively. A greater agreement between the model and experimental values is observed for the higher temperatures and the longer reaction time. Larger deviations were observed for the PLA toy, which we attribute to the presence of additives, since despite its lower molecular weight, it possessed a higher structural strength.

Existing feeding practices and production performance of lactating buffaloes in selected agro-climatic zones of Bangladesh

A study was conducted to observe the existing feeding practices, nutritional supply and production performance of the lactating buffaloes in some selected agro-climatic zones of Bangladesh, viz. Bhola (AEZ-18, Coastal area), Mymensingh (AEZ-22, River basin area) and Dinajpur (AEZ-27, Drought area). Data on availability, amount and types of feeds and fodders fed to the lactating buffaloes, body weight, milk yield and quality and lactation length were collected from 30 farmers of the each selected locations. In this investigation, the mostly used feed ingredients found were rice straw, locally available green grasses, wheat bran, broken maize, mustard oil cake and broken rice. Total feed supply (DM kg/h/d) to lactating buffaloes were 17.4, 14.5 and 13.0 in coastal, river basin and drought areas, respectively, (p&gt;0.05). But significantly (p = 0.000) different amount (DM kg/h/d) of concentrate were supplied in coastal (1.5), river basin (1.8) and drought (2.7) areas. The highest amount (kg/h/d) of green grass was supplied in coastal area (5.0) followed by river basin area (4.3) and drought area (1.3). Accordingly, amount (kg/d) of DCP and TDN were supplied was higher in coastal area (0.365 and 6.417, respectively) than that of the river basin and drought areas (0.247-0.248 and 5.501-5.891, respectively), which were below their requirements. Significantly (p=0.000) larger lactating buffaloes were found in the river basin and drought areas (weighed 372–380 kg/h) than that of coastal area (242 kg/h). The average daily milk yield was found significantly highest (p=0.000) in the drought area (5.3 L/d) which was 1.4 L and 3.1L more than that of the river basin and coastal area, respectively. The 4% FCM yield was found two times more (p=0.000) in drought area (7.7 kg/d) than that of the coastal (3.1 kg/d) and river basin (3.6 kg/d) area. On the other hand, the significantly (p=0.000) highest lactation length and lactation yield were 294 d and 1085 L, in the river basin area, which were 189 d and 1007 L in drought area and 197d and 429 L in coastal area, respectively. Among the milk constituents, protein, ash and lactose content was found higher in drought area than that of the other two areas (p=0.001). In conclusion, the prevailing variations are evidently considerable. Therefore, suggesting further works for large scale baseline data regarding buffalo populations, nutritive quality of feeds and fodder, effectiveness of existing management tools and adoption of new technologies.&#x0D; Bang. J. Anim. Sci. 2019. 48 (2): 127-138

Comparative analysis of performance traits of different dairy cattle reared in the Srinagar city of J&K.

Breed structure of cattle in Jammu and Kashmir has changed over the last decades due to influx of different type of cattle from outside and implementation of various cattle developmental programmes. Presently, around 50% of the total cattle population has been upgraded into high yielding crossbred varieties, with highest proportion seen in the Srinagar District. A study was planned with the objective of studying the performance traits of these crossbred cows in the Srinagar District of J&K. Lactation yield, peak milk yield and daily milk yield was observed to be significantly higher in HFCB cows than JCB cows. Lactation length was significantly longer in JCB cows than HFCB cows. Gestation period and calving interval was longer in HFCB cows than JCB cows, whereas service period and age at first calving was longer in JCB cows than HFCB cows. Dry period was slightly higher for JCB cows than HFCB cows. Birth weight was significantly more in HFCB calves than JCB calves. It was concluded that both crossbreds performed well in the local conditions of Srinagar District of J&K.

Buffaloes Production and Reproduction Efficiencies as Reviewed for Parity in Nepal

Buffalo rearing is major part of Nepalese agriculture and they are reared for milk, meat, draft power and manure. Buffaloes are the main source of milk production in Nepal producing about 65.3% of the total annual milk in the country. Different indigenous breeds such as Lime, Parkote and Gaddi as well as Indian Murrah and Nili Ravi are recorded in Nepal and they are raised in different management and production system. Different genetic and non-genetic factors cause variation in production and reproduction performance between these breeds and within these breeds also. Non genetic factors affecting the performance of these buffaloes are season of calving, parity, management practices, nutrition etc. In this paper, effect of parity on production traits such as colostrum period, lactation length, lactation yield and days to reach peak milk yield as well as reproduction traits such as calving interval, dry period and service period are reviewed. Thus, this paper after reviewing related articles from various journals, proceedings and magazines is aimed to evaluate the effect of parity on reproductive and production efficiency of buffaloes of Nepal. Though the performance of indigenous breed is generally considered low, there is high potential of these breeds under proper breeding and management programs.&#x0D; Int. J. Appl. Sci. Biotechnol. Vol 8(1): 1-6.

Determination of some serum macroelement minerals levels at different lactation stages of dairy cows and their correlations

Minerals levels in blood affects animal performance, such as reproduction, immunity, and lameness. Minerals blood levels are recorded for all world tropics to be affected by lactation yield. This study aims to determinate the effects of different lactation stages of dairy cows on the serum Ca, P, Mg, Na and K minerals levels.The study involved 37 dairy cows, of parity order ranging between 2 to 6, at different stages of lactation. The animals were divided into four groups based on their stage of lactation, including postpartum, early, mid, and late stage cows. At the different lactation stages, serum profiles of Ca, P, Na, K and Mg as well as average daily milk yield were estimated. The data of serum profile was analyzed for the significance of stage of lactation by analysis of covariance, taking parity order as a covariate.The descriptive statistics of the studied traits showed that calcium serum level showed the most discrepancies among observations (coefficient of variation of 73.39%), whereas sodium serum level had the lowest level of discrepancies (coefficient of variation of 2.41%). The average daily milk yield was significantly higher at mid stage of lactation than those at the other stages of lactation. Serum level of all of the studied macro minerals were not statistically variable among stages of lactation, however, calcium showed statistically insignificant high levels during the early and mid of lactation, whereas, showed the lowest level at prepartum and postpartum stages. Calcium positively correlated with daily milk yield and negatively with potassium serum level.Results offer a base-line data concerning minerals levels during different lactation stages specially during prepartum and postpartum for normal healthy cows. Different lactation stages may affect and determinate macro-elements minerals levels. prepartum and postpartum periods are the most important stages that affects minerals levels. Some minerals showed tendency to correlate positively or negatively with other.