Peak Yield Research Articles

Estimation of Non-genetic Parameters Affecting Total Milk Yield and Occurrence of Mastitis in Holstein Friesian Dairy Cows

This study was performed on 1480 productive records collected from private farm of Holstein Friesian cows. In addition, collection of 70 milk samples for the measurement of somatic cell count (SCC). This study aims to evaluate the effect of some non-genetic factors (days in milk (DIM), peak milk yield (PMY), dry period (DP), calving interval (CI), parity, and season of calving) on total milk yield (TMY). And studying the effect of 305-day milk yield (305-DMY), peak milk yield (PMY), days in milk (DIM), parity and season of calving on mastitis in Holstein Friesian cows. All data were analyzed by general linear model (GLM) using SAS software ver.9.1.3. The current results revealed that DIM and parity had a significant effect on TMY, where the highest milk yield was obtained when DIM were more than 357 days and in the 3rd lactation season. Season of calving showed a significant effect on mastitis disease, where the highest incidence of mastitis was recorded for spring calvers.

Estimates of genetic parameters of economic traits in murrah buffaloes

Data from 1991 to 2017, pertaining to early performance traits was collected from 659 Murrah buffaloes, sired by 188 bulls, maintained at Directorate of Livestock Farms, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab. Least squares means and effect on non-genetic factors were evaluated for economic traits. Moderate heritability estimates of 0.217 ± 0.00, 0.231 ± 0.00, 0.260 ± 0.046 were calculated for first calving interval (FCI), First 305 day milk yield (F305MY) and first peak yield (FPY) respectively and low heritability values of 0.015± 0.025 and 0.043 ± 0.03 were estimated for age at first calving (AFC) and first lactation length (FLL) respectively. The phenotypic and genetic correlation of AFC was found to be positive with FLL and FCI and negative with F305MY and FPY. Although the production efficiency traits like F305MY, FLL and FPY had high positive genetic and phenotypic correlation among themselves.

Catalytic conversion of glycerol to bio-based aromatics using H-ZSM-5 in combination with various binders

The use of H-ZSM-5 with various binders (Al2O3, SiO2, and kaolinite, 10 wt% on catalyst formulation) for the catalytic conversion of glycerol to bio-based aromatics (GTA) was investigated in a continuous bench-scale unit at a pyrolysis temperature of 450 °C, catalytic upgrading temperature of 500 °C, WHSV of pure glycerol of 1 h−1, and atmospheric pressure, and their performance was compared to H-ZSM-5 (SiO2/Al2O3 molar ratio of 28). The latter gave a peak BTX carbon yield of ca. 31.1C.%, a life-time of ca. 220 min, and a total BTX productivity of ca. 312 mg BTX g−1H-ZSM-5. The introduction of binders affects catalyst performance, which is the most profound and promising for the H-ZSM-5/Al2O3 catalyst. It shows a prolonged catalyst life-time of ca. 320 min and a higher total BTX productivity of ca. 518 mg BTX g−1H-ZSM-5, compared to the H-ZSM-5 without a binder. Catalyst characterization studies show that the addition of the binder does not have a major effect on the specific surface area, total pore volume, and total acidity. Other relevant properties were affected, though, such as micropore volume (SiO2), a reduced Brønsted acidity (Al2O3, and SiO2), and reduced crystallinity (SiO2). Coke formation causes severe catalyst deactivation, ultimately leading to an inactive catalyst for BTX formation. Catalyst characterization studies after an oxidative regeneration showed that the textural properties of the regenerated catalysts were close to those of the original catalysts. However, some dealumination of H-ZSM-5 occurs, resulting in decreased crystallinity and acidity, causing irreversible deactivation, which needs attention in future catalyst development studies.

Persistence of the yield advantage of perennial ryegrass cultivars: concept, evidence and implications

Pasture persistence can be defined several ways, but a key outcome for farmers is that the yield advantage of a new pasture compared to the pasture it replaced persists for several years after sowing. The concept of persistence of the yield advantage can also be applied to genetic evaluation of cultivars in species such as perennial ryegrass to determine the true value of pasture renewal and cultivar selection. We analysed 8 years of yield and tiller density data from pastures sown to four perennial ryegrass cultivars representing different functional types at two locations, Waikato (non-irrigated) and Canterbury (irrigated). ‘Grasslands Nui’ SE (Nui) was designated as the baseline cultivar. A significant yield advantage over Nui was observed for two cultivars (Alto AR37 and Halo AR37). Peak yield advantage occurred 4 or 5 years post-sowing, then declined by approximately 50% and became nonsignificant by Year 8. The pattern was very similar at both locations. Tiller density data indicated a shift in sward structure over time consistent with size-density trade-offs in the diploid cultivar Alto AR37 but not in the tetraploid cultivar Halo AR37. The implications for economic evaluation systems such as the DairyNZ Forage Value Index are discussed.

Metal speciation distribution of anaerobic fermentation with alfalfa grass harvested from abandoned iron mine and the influence of metals addition

Metal-contaminated plants after phytoremediation provide organic matter and trace metals for anaerobic fermentation. In this study, alfalfa straw harvested from an abandoned iron mine was used for anaerobic fermentation. The variation of metal speciation during the anaerobic fermentation process and the influences on fermentation parameters were investigated. The results showed that the group adding alfalfa increased the peak daily biogas yield by 33.40 % compared to the group with cow dung only. Fe in the fermenter was predominated by the soluble and the residual fraction. Cu was transformed from soluble Cu to residual Cu with the fermentation progressed. On the 13th day of fermentation, the percentage of soluble Fe decreased while the percentage of soluble Cu, Ni and Zn increased which induced the daily biogas yields peak. Metal speciation was correlated to the fermentation parameters. Daily biogas yields were negatively correlated to the acid-extractable fraction of Ni and Zn (p < 0.05). pH was negatively correlated to the soluble Cu, the acid-extractable fraction of Cu and Zn (p < 0.05), while positively correlated to the reducible and oxidizable Fe (p < 0.01). Further adding metals promoted the biogas production of alfalfa by bringing forward the daily biogas peak and increasing the peak yields. In particular, adding Cu only produced more biogas than adding other metals (single or multiple). Exogenous metals addition generally resulted in more acid-extractable fraction of Cu, Ni and Zn, i.e. the mobility of these metals increased. 19 % of Fe was activated into acid-extractable fraction after the addition of Ni. The results of this study are expected to provide references for the reutilization of contaminated biomass and optimizing the metal contained fermentation process.

Association analysis between FASN genotype and milk traits in Mediterranean buffalo and its expression among different buffalo tissues

Fatty acid synthase (FASN) is a multifunctional protein that catalyzes the synthesis of long-chain saturated fatty acid. In this study, we identified the single nucleotide polymorphisms (SNPs), and their association with milk traits in Mediterranean buffalo, and the expression of FASN gene in different tissues was measured. Nine SNPs (g.-1640G > A, g.-1099C > T, g.1095C > A, g.3221G > A, g.4762G > A, g.5299G > A, g.7164G > A, g.7272T > C, and g.8927T > C) were identified by DNA pooled sequencing and then genotyped. Seven identified SNPs except g.3221G > A and g.8927T > C were found significantly associated with both fat and protein percentage, and also the g.7164G > A and g.8927T > C had significant association with peak milk yield and protein percentage, respectively. One haplotype block was successfully constructed by linkage disequilibrium (LD) analysis and it showed a significant association with both fat percentage and protein percentage. Expression of FASN gene was found in almost all the buffalo tissues including mammary gland, heart, liver, spleen, lung, kidney, uterus, and ovary, and to be highest in lung and mammary gland. Our findings suggest that polymorphisms in the buffalo FASN gene are associated with milk production traits and can be used as a candidate gene for milk traits and marker-assisted selection in buffalo breeding program.

A COMPREHENSIVE REVIEW ON MILK YIELD, LACTATION EFFICIENCY, MILK COMPOSITION AND MASTITIS INCIDENCE AT DIFFERENT PARITY IN MURRAH BUFFALOES

Murrah buffaloes are the most important milch animal which has gained immense popularity due to its higher milk production capacity coupled with adaptation to wide ecological conditions and feed conversion efficiency. Milk yield, milk composition, lactation efficiency, and severity of mastitis varies with parity. The main objective of this article is to review the existing literature regarding the effect of parity on milk yield, lactation efficiency, milk composition, and mastitis in Murrah. Parity plays a crucial role in the productivity, profitability, and economic efficiency of Murrah buffaloes. Most of the researchers reported that parity has a significant effect on 305 MY, Total milk yield, milk composition while the non-significant effect on colostrums period, lactation length, and mastitis. Milk quantity and quality was superior in mid parity as compared to early and late parity. Days to reach peak milk yield, dry period, and mastitis incidence were reported minimum in mid parity. The milk of Murrah is mainly composed of water, lactose, fat, solid not fat, total solid, vitamins, minerals, casein, and protein. Milk constituents such as protein, casein, lactose were superior in mid parity except for milk fat and total solid due to reduced milk yield. However, the research paper regarding the effect of parity on most of these parameters is very scanty. So, further research should be conducted using a large sample size and wider agro-ecological zones to gain a better understanding and to obtain a more precise result.

Microstructure Evaluation, Quantitative Phase Analysis, Strengthening Mechanism and Influence of Hybrid Reinforcements (β-SiCp, Bi and Sb) on the Collective Mechanical Properties of the AZ91 Magnesium Matrix

Gravitational melt-stir casting produced hybrid nano-reinforcements (β-SiCp) and micro-reinforcements (Bi and Sb) of AZ91 composites. SiCp-diffused discontinuous β-Mg17Al12 precipitation with a vital factor of SiC was exhibited at the grain boundary region, formulated Mg3Si throughout the composite and changed the present Mg0.97Zn0.03 phases. The creation of Mg2Si (cubic) and SiC (rhombohedral axes) enhanced the microhardness by 18.60% in a 0.5 wt.% SiCp/AZ91 matrix. The microhardness of 1 wt.% SiCp/AZ91 was slightly reduced after Mg0.97Zn0.03 (hexagonal) reduction. The best ultimate tensile value obtained was about 169.33 MPa (increased by 40.10%) in a 0.5 wt.% SiCp/AZ91 matrix. Microelements Bi and Sb developed Mg3Bi2, Mg3Sb2 and monoclinic C60 phases. The best peak yield strength of 82.75 MPa (increased by 19.85%) was obtained with the addition of 0.5 wt.% SiCp/1 wt.% Bi/0.4 wt.% Sb. The mismatch of the coefficient of thermal expansion of segregated particles and the AZ91 matrix, the shear transfer effect and the Orowan effect, combined with the quantitative value of phase existence, improved the compressive strengths of the composites with 0.5 wt.% β-SiCp, 1 wt.% β-SiCp and 0.5 wt.% SiCp/1 wt.% Bi/0.4 wt.% Sb by 2.68%, 6.23% and 8.38%, respectively. Notably, the Charpy impact strengths of 0.5 wt.% and 1 wt.% β-SiCp-added AZ91 composites were enhanced by 236% (2.89 J) and 192% (2.35 J), respectively. The addition of Bi and Sb with SiCp resulted in the formation of a massive phase of brittle Al6Mn. Al–Mn-based phases (developed huge voids and cavities) remarkably reduced impact values by 80% (0.98 J). The discussion covers the quantitative analyses of X-ray diffraction, optical microscopy and scanning electron microscopy results and fracture surfaces.

Performance Evaluation, Genetic Parameter and Genetic Trend Estimation of Production and Reproduction Traits of Sahiwal Cattle in Chhattisgarh

Background: Performance evaluation is necessary for formulation of suitable breeding plans for genetic improvement in a population. Therefore, this study aimed to assess the production, reproduction performances and estimate the genetic parameter and genetic trend on 649 lactation records of 238 Sahiwal cows at an organized farm in Chhattisgarh. Methods: The analysis was performed by using fixed model in LSML. Genetic trend for traits was estimated through linear regression of breeding values over the years.Result: Least-squares means for total lactation milk yield (TLMY), 305day or less milk yield (305DMY), lactation length (LL), dry period (DP) and peak yield (PY) were 1385.1±26.7 kg, 1331.4±23.6 kg, 291.0±3.7 days, 214.8±6.0 days, 7.5±0.1 kg, while for reproduction traits; age at first calving (AFC), service period (SP) and calving interval (CI), the means were 1522.8±19.1 days, 212.4±5.9 days and 498.3±6.0 days, respectively. All the traits were significantly influenced by period of calving/birth whereas season had significant effect only on PY. The highest heritability (0.29 ± 0.05) was estimated for 305DMY and lowest (0.11 ± 0.07) for SP in Sahiwal cows. Very high and positive genetic correlations was found among production traits. The first lactation 305DMY showed positive genetic trend, while LL, DP, SP and CI showed a negative genetic trend.

Associations between feed efficiency and aspects of lactation curves in primiparous Holstein dairy cattle

Genetic selection for improved feed efficiency in dairy cattle has received renewed attention over the last decade to address the needs of a growing global population. As milk yield is a critical component of feed efficiency metrics in dairy animals, our objective was to evaluate the associations between feed efficiency in primiparous Holstein cattle and parameters of a mathematical model describing individual lactation curves. The Dijkstra lactation curve model was fit to individual lactation records from 34 Holstein heifers with previously estimated measures of feed efficiency. We found that the optimal fit of the Dijkstra model was achieved using daily milk yield records up to 21 d in milk to capture the rise to peak milk yield and using monthly dairy herd improvement records for the remainder of lactation to accurately characterize lactation persistency. In the period of lactation before peak milk yield, improved feed efficiency was associated with a faster increase in daily milk yield over a shorter period of time at the expense of increased mobilization of body reserves; this serves to reinforce the concept that dairy cattle are primarily capital breeders versus income breeders. Feed efficiency in the period following peak lactation, as measured by gross feed efficiency, return over feed costs, and net energy efficiency of lactation, was positively associated with higher peak milk yield. The findings in early lactation suggest that estimates of feed efficiency could be improved by evaluating feed efficiency relative to conception, rather than parturition and lactation, to better account for the energy stored and released from body reserves in capital breeding.

Productive and reproductive performance of Siri cattle under field condition in West Bengal

A study was undertaken with an objective to assess productive and reproductive performance of Siri cattle in West Bengal. The study was conducted among 80 farmers rearing either Siri-Pure or Siri-Graded cattle in the hilly region. Equal numbers of respondents either rearing Siri-Pure or Siri-Graded cattle were randomly selected from Darjeeling and Kalimpong districts for the study. The study on productive performance of Siri-Pure and Siri- Graded cattle shows that mean first lactation milk yield was 469.7 and 497.2 litres, daily milk yield was 3.2 and 3.7 litres, peak milk yield was 3.8 and 4.2 litres, total lactation milk yield was 864.1 and 1035.5 litres, lactation length was 273.4 and 284.8 days and dry period was 189.3 and 167.9 days. The t-test shows highly significant difference between Siri-Pure and Siri-Graded cattle in first lactation milk yield, daily milk yield, total lactation milk yield and lactation length in productive performance whereas age at first services, calving intervals and gestation period in reproductive performance. The reproductive performance of Siri-Pure and Siri-Graded cattle shows that mean age at first services was 38.47 and 31.65 months, gestation period was 285.2 and 279.1 days, heat interval was 27.8 and 28.2 days, number of services per conception was 1.3 and 1.3 times, and calving intervals recorded as 463.7 and 452.7 days respectively. The age at first service was significantly lower in large farmers and significantly higher calving interval in small farmers rearing Siri-Pure cattle. Daily milk yield, peak milk yield and total milk yield was significantly higher in large and medium farmers than small farmer rearing Siri-Pure cattle whereas total milk yield was significantly higher in large farmers than small and medium farmers rearing Siri-Graded cattle.

Effects of oxygen on soot formation in laminar co-flow flames of binary mixtures of ethane, DME, and oxygen

Soot volume fractions of binary mixtures of ethane, DME and oxygen were evaluated experimentally in a co-flow burner. Soot volume fractions were measured by diffuse-light line-of-sight attenuation technique. The carbon mass flow rate and the C/H ratio were kept constant for all mixtures, while oxygen was introduced into the fuel stream either as an additive or as intramolecular oxygen in DME or both. Visible flame heights were decreased with increasing oxygen in the fuel stream. Binary mixtures of ethane and DME did not show any synergistic effects on soot formation. The maximum soot volume fraction was decreased from 1.41 ppm in the neat ethane flame to 0.08 ppm in the neat DME flame. On the other hand, oxygen addition to either ethane or DME resulted in an increase in soot concentrations. The maximum soot volume fraction reached to 2.1 ppm and 0.29 ppm in ethane/oxygen and DME/oxygen mixtures, respectively. The peak soot yield initially decreased for all mixtures studied as oxygen was introduced into the fuel tube. A unique transition was observed in DME/oxygen mixtures at an equivalence ratio of 6.8. When more oxygen was added beyond this ratio, the effect of oxygen on soot formation was suddenly reversed, and the peak soot volume fraction and yield were significantly decreased. This sudden reversal was explained as a result of a transition into a more premixed mode of combustion, supported by the flame images as well as chemiluminescence measurements. A distinct two-zone flame structure, that is, an inner rich zone and an outer stoichiometric zone separated by a dark region, was observed for the neat DME flame and DME/oxygen mixture flames. It is argued that as oxygen becomes available from DME decomposition, it produces a premixed region, and the flame chemistry is significantly altered beyond a critical oxygen concentration. Current radially resolved soot volume fraction measurements suggest that the effects of oxygen on soot formation can be quite complex with nonmonotonic behaviour, sudden effect reversals and shifts in soot formation and oxidation zones.

Genetic Association of PPARGC1A Gene Single Nucleotide Polymorphism with Milk Production Traits in Italian Mediterranean Buffalo.

PPARGC1A gene plays an important role in the activation of various important hormone receptors and transcriptional factors involved in the regulation of adaptive thermogenesis, gluconeogenesis, fiber-type switching in skeletal muscle, mitochondrial biogenesis, and adipogenesis, regulating the reproduction and proposed as a candidate gene for milk-related traits in cattle. This study identified polymorphisms in the PPARGC1A gene in Italian Mediterranean buffaloes and their associations to milk production and quality traits (lactation length, peak milk yield, fat and protein yield, and percentage). As a result, a total of seven SNPs (g.-78A>G, g.224651G>C, g.286986G>A, g.304050G>A, g.325647G>A, g.325817T>C, and g.325997G>A) were identified by DNA pooled sequencing. Analysis of productivity traits within the genotyped animals revealed that the g.286986G>A located at intron 4 was associated with milk production traits, but the g.325817T>C had no association with milk production. Polymorphisms in g.-78A>G was associated with peak milk yield and milk yield, while g.304050G>A and g.325997 G>A were associated with both milk yield and protein percentage. Our findings suggest that polymorphisms in the buffalo PPARGC1A gene are associated with milk production traits and can be used as a candidate gene for milk traits and marker-assisted selection in the buffalo breeding program.

Assessment the gas potential of coal-bearing mudstones from upper paleozoic in ordos basin via gold-tube pyrolysis

Previous natural gas explorations in Ordos Basin were conducted in areas with thick coal deposited. Recently, natural gas flow were discovered in southern basin where very thin coal seams were developed, implying the contribution from other source rocks, e.g. the coal measure mudstones. In order to thoroughly assess the quality and gas potential of coal measure mudstones, 58 mudstones from borehole were analyzed by Rock-Eval method and gold-tube pyrolysis was carried out on immature carbonaceous and dark mudstones with detailed geochemical characteristics of hydrocarbon products detected.The results indicated the mudstones were dominated by type III kerogen and assisted by type II kerogen and were fair to good source rocks. Pyrolysis data demonstrated the peak yield of C1-5 for carbonaceous mudstone was very close to that of coal, whereas the maximum C1-5 yield for dark mudstone accounted for 62.5% of that of carbonaceous mudstone, indicating the good gas potential of carbonaceous mudstone. The generated gaseous hydrocarbons were predominately derived from primary kerogen cracking.The computed activation energy of C1-5 for carbonaceous mudstone showed a more discrete distribution compared to dark mudstone. The modeled methane conversion for dark mudstone was higher than that of carbonaceous mudstone since entering main gas generation stage, which was consistent with the concentrated and lower activation energies for dark mudstone. Furthermore, the modeled gas in southern basin was much higher than that in central basin, due to the more severe thermal alteration that coal measures in southern basin had experienced.On the basis of the integrated analysis of methane generation and adsorption, the areas with thick carbonaceous mudstone deposited had fair exploration prospects and further gas explorations should pay more attention on.

Association between early postpartum rumination time and peak milk yield in dairy cows

Limited information is available on the relationship between rumination time (RT) in the early postpartum period and milk production later in lactation. Therefore, the objectives of this study were to (1) investigate the association of change in RT and average RT during the immediate postpartum period with peak milk yield (PMY) in dairy cows, and (2) determine the best model based on days in milk (DIM) to evaluate this association. Cows from 33 free-flow automatic milking system farms were included in this study, where retrospective milk production and RT data were collected for 12 mo. Cows were categorized by parity number into parity 1 (P1, n = 1,538), parity 2 (P2, n = 1,354), or parity ≥3 (P3+, n = 1,770). For each cow, PMY was identified as the highest daily milk yield up to 180 DIM for P1 and 120 DIM for P2 and P3+ cows. Five change in RT variables and 5 average RT variables were created corresponding to the first 2 to 6 DIM. Change in RT variables were the slope coefficients for change in RT/d related to DIM = 1 extracted from simple linear regressions, and average RT variables were the arithmetic mean RT. Five models analyzing PMY and corresponding variables calculated over the first 2 to 6 DIM had fixed effects of average RT, change in RT, parity, average RT × parity interaction, change in RT × parity interaction, and a random intercept for farm. Peak milk yield occurred at (median) 75, 44, and 46 DIM for P1, P2, and P3+, respectively. Overall PMY was (mean ± standard deviation) 54 ± 11 kg and it increased as parity increased. A positive association was found between change in RT and PMY, and average RT and PMY for P2 and P3+ cows in all 5 models corresponding to the first 2 to 6 DIM, indicating that greater average RT and quicker increase in RT after calving are associated with greater PMY for multiparous cows. Although the model including all 6 DIM had the greatest accuracy, results indicated that rumination data collected over the first 2 DIM may also provide adequate information for the association of average RT and change in RT with PMY in P2 and P3+ cows. For each 100 min/d increase in change in RT over the first 6 DIM, PMY increased by 4.3 (95% confidence interval: 2.2-6.3) and 4.8 (95% confidence interval: 3.2-6.5) kg for P2 and P3+ cows, respectively. Peak milk yield increased by 2.3 (95% CI: 1.7-2.8) and 2.2 (95% confidence interval: 1.7-2.6) kg for each 100 min increase in average RT over the first 6 DIM for P2 and P3+ cows, respectively. No association was observed between rumination behaviors and PMY for P1 cows. Results from this study indicate that the length of time for multiparous cows to achieve a stable RT in the early postpartum period combined with average RT during the same period may be useful in predicting their overall lactation milk production.

Genetic principal components for reproductive and productive traits in Holstein cows reared under tropical conditions.

The objective of this study was to compare the standard multi-trait model and five reduced-rank models fitted to the first principal components and genetic parameter estimates in order to determine the most appropriate method to model the covariance structure of reproductive and productive traits in Brazilian Holstein cows. Individual records of the following traits from 5217 cows were analyzed: 305-day milk yield (MY305), peak yield, milk yield per day of calving interval, days from calving to first estrus, days from calving to last service (CLS), calving interval (CI), and gestation length. Schwarz's Bayesian information criterion was used to compare the different models. The results indicated that four principal components were necessary to model the genetic (co)variance structure, reducing the number of parameters to be estimated. Analysis of genetic and phenotypic correlations showed that milk production-related traits were strongly correlated with each other (ranging from 0.74 to 0.99), while the correlation of these traits with the reproductive traits was weak (ranging from - 0.14 to 0.27). Heritability estimates for the traits ranged from 0.03 to 0.18. The reproductive traits CLS and CI and the production trait MY305 should be included as selection criteria in dairy cattle breeding programs because they are correlated with the first two principal components, retaining 91% of the genetic variability of the data.

Sub-acute ruminal acidosis: Understanding the pathophysiology and management with exogenous buffers

Sub-acute ruminal acidosis (SARA) is an economically important clinical condition and contributes to loss of farm returns, second only to mastitis. It is more prominent in cows in their early and mid-lactation, having peak milk yield and considerably high dry matter intake. SARA detection in a dairy farm is difficult as it does not present any pathognomonic symptoms, and the manifestation of clinical signs is delayed. SARA's characteristic feature is the occurrence of daily fluctuations of pH when the pH drops to the range of 5.2 to 6 for a considerable period due to the accumulation of volatile fatty acids in the rumen. Grain-based diets, which have higher proportions of non-structural carbohydrates, high-quality fermentable forages like legumes, and lack of physically adequate dietary fibre (peNDF), are the significant causes of SARA. SARA consequences include the inflammation of rumen mucosa and several other organs and long-term health and economic losses like reduced feed intake reduced fibre degradability, drop in milk yield and milk fat, damage to the gastrointestinal tract, laminitis, liver dysfunctions, and lameness. SARA can be prevented and treated by the right combination and judicious use of exogenous dietary buffers like sodium bicarbonate, magnesium oxide, and direct-fed microbial like yeast. This review aims to provide a gist of the recent literature available on the pathophysiological aspects, indicators, detection techniques, prevalence, and preventive measures for SARA, including the mechanism of action and utility of the commonly used dietary buffers and direct-fed microbials.

Risk factors associated with testing positive for tuberculosis in high-yielding Holstein cows

Tuberculosis remains a significant infectious disease of farm animals and humans worldwide. The objective of this study was to assess various risk factors associated with testing positive for bovine tuberculosis (bTB) in high-yielding Holstein cows in an intensive dry-lot dairy operation. In a retrospective observational study, 9312 records from Holstein cows from a large dairy herd in northern Mexico were used. The incidence rate of lactating cows reactor to bTB was 7.3 cases/100 cow years (95% CI = 6.7-7.9%). Multiple logistic regression models indicated that cows with total milk yield during the first lactation >10,200 kg were 1.3 times (95% confidence intervals (CI) for odds ratio (OR) = 1.2-1.6) more likely to be detected as bTB reactors than cows with total milk yield <10,200 kg (8.2 vs. 6.4%; P < 0.01). The risk of being reactor to bTB increased with x̅ total milk yield/lactation >11,500 kg (OR=2.7, 95% CI = 2.3-3.3; 10.4 vs. 4.2%) compared with cows with x̅ total milk yield/lactation <11,500 kg. Cows with >10,200 kg 305-day milk yield in the last lactation was associated (P < 0.01) with 1.3 times higher odds (95% CI for OR = 1.1-1.5) of being classed as reactors than cows with <10,200 kg. Cows with peak milk yield >48 kg were 1.9 times (95% CI for OR = 1.6-2.2) more likely to be reactor to bTB than cows with peak milk yield <48 kg (9.2 vs. 5.1%; P < 0.01). Cows with either puerperal metritis (OR = 0.07, 95% CI = 0.5-0.9) or carrying twins (OR = 0.05, 95% CI = 0.01-0.19) had a protective role for being reactor to bTB. This study showed that increased milk production was associated with a higher risk of becoming positive to tuberculin skin test in high-yielding Holstein cows.

Derivates variation of phenylalanine as a model disinfection by-product precursor during long term chlorination and chloramination

Dissolved nitrogenous organic matter in water can contain precursors of disinfection by-products (DBPs), especially nitrogenous DBPs (N-DBPs). Amino acids are ubiquitous as dissolved nitrogenous organic matter in source water and can pass through drinking water treatment processes to react with disinfectants in finished water and in the distribution system. Phenylalanine (Phe) was selected as a model amino acid precursor to investigate its derived DBPs and their variations during a chlorination regime that simulated water distribution with residue chlorine. The 7-day DBPs formation potential (DBPsFP) test with chlorine revealed chlorination by-products of phenylalanine including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and halonitromethanes (HNMs), but not trichloronitromethane (TCNM) which was a significant N-DBP detected during the first 48 h of chlorine contact. The formation of most carbonaceous DBPs (C-DBPs) increased with chlorination time; however N-DBPs and non-chlorinated byproducts of phenylacetonitrile and phenylacetaldehyde reached their highest concentration after 2 h of reaction, and then gradually decreased until below detection after 7 days. The chlorination influencing factors indicated that light enhanced the peak yield of DBPs; the pH value showed different influences associated with corresponding DBPs; and the presence of bromide ions (Br−) generated a variety of bromine-containing DBPs. The DBPsFP test with chloramine reduced C-DBPs generation to about 1/3 of the level observed for chlorine disinfection and caused an increase in dichloroacetonitrile. Surveillance of DBPs during drinking water distribution to consumers should consider the varying contact times with disinfectants to accurately profile the types and concentrations of C-DBPs and N-DBPs present in drinking water.

Factors Affecting Lactation Length and Peak Milk Yield in Gir Cattle

The production records of 228 Gir cows with 680 lactations sired by 52 bulls, maintained at Cattle Breeding Farm, Junagadh, were studied for 24 years (1987-2010). The data were analyzed to study the effect of period of calving, season of calving and parity as fixed effect on the production traits, viz., lactation length and peak milk yield. The least squares means of lactation length and peak milk yield in Gir cows were found to be 328.27 ± 12.99 days and 12.31 ± 0.51 kg, respectively. The variance analysis revealed that the period of calving and parity had a highly significant (p less than 0.01) influence on average lactation length and peak milk yield in Gir cows. Effect of season of calving was non- significant on these traits, indicating breed characteristic to adopt with tropical environment. There was precise decreasing trend in the lactation length due to parity or sequence of calving, indicating decrease of lactation length as the age advances, whereas peak milk yield increased gradually till 5th parity and then declined with advancing age/parity till 11th lactation. Lactation length ranged from 408.78 to 268.93 days in 1st to 12th parity, while peak milk yield in 1st, 5th and 10th lactation was 9.48, 13.65 11.17 kg, respectively.