Lactation Milk Research Articles

Behaviour of Cows with Johne’s Disease (Paratuberculosis)

Johne’s disease (JD) significantly reduces the welfare of cattle worldwide. As changes in lying and feeding behaviours are considered important tools for assessing health and early detection of diseases, the aim of this study was to compare lying and feeding behaviours of JD-positive (JD5) and JD-negative (JD0) cows around peak lactation. The cows were fitted with an accelerometer-based sensor to record step counts and lying behaviour. They were also fitted with a pressure-based halter from approximately 56 d post-partum to collect feeding and rumination data. Every 3 months, the cows were milk sampled to test for naturally occurring JD using an ELISA. JD5 cows [n = 14 (two positive results in any four consecutive ELISAs)] were matched to JD0 cows [n = 14 (consecutive negative ELISAs)] based on lactation stage, parity, age, and milk yield. Of the 28 cows, 9 JD5 and 9 JD0 cows provided sensor data for analysis. JD5 cows spent 1.7 h/d less lying compared to JD0 cows. No differences in time spent eating were found; however, JD5 cows spent 1.1 h/d longer ruminating and produced 80 more feed boluses/d than JD0 cows around week 8 of lactation. The reason JD5 and JD0 cows behave differently around peak lactation is unclear and therefore warrants further investigation focusing on behaviour, milk yield, and feed intake among cows with JD.

Genetic improvement of indigenous cattle breeds in Ethiopia: A systematic review of the Fogera cattle open nucleus breeding scheme

Fogera cattle are one of the valuable indigenous milk-type local breeds of Ethiopia, widely adapted to the area around Lake Tana in the Amhara region. The objective of this systematic review was to evaluate the performance of the Fogera cattle breed under an open nucleus breeding scheme. The review was done systematically by collecting published and unpublished data sources on the breed. The overall milk yield of the nucleus Fogera cattle herd was 2.26±0.794L/day. From the total herd, the top 10% and 25% of them produced daily milk yields of 3.31 and 2.87L, respectively, and some elite cows gave an average of 5.45±0.73L/day with a maximum yield of 8L/day. The predicted 305-day milk yield for the top 10% and 25% of the total herd was 883.64 and 772.83L, respectively. The average lactation milk yield and lactation length were reported to be 489±184L and 243±72.79 days, respectively. The respective heritability estimates for the aforementioned traits were 0.20±0.23 and 0.27±0.001. The birth and weaning weights (at 8 months of age) of village Fogera cattle born from community-based breeding programmes (CBBP) were 23.77±.21 and 85.89±1.07kg, respectively. The average weaning age for the CBBP herds was reduced to 8 months. The overall calf mortality in the nucleus herd was 3%. The CBBP demonstrated that it could act as a significant entry point for ensuring the conservation and restocking efforts of this breed as a country asset.

Genetic Evaluation of Monthly Test-Day Milk Yields of Jersey Crossbred Cattle Under Farmers' Production System in Tamil Nadu, India.

Tamil Nadu, a state in southern India, is bereft of any native dairy or dual-purpose cattle breeds, and the state depends chiefly on crossbred cattle for milk production. Jersey crossbred cattle account for 90% of the state's milk production. This genetic evaluation study aimed to assess milk production traits, including test-day milk yields (TDMYs), total lactation milk yield (TMY), and 305-day milk yield (305MY), in these cattle reared under farmers' conditions. Data on monthly TDMYs (TDMY1 to TDMY10) of Jersey crossbred cows (n = 75,627) reared by the farmers over 11 years (2012-2022) were collected for evaluation. The influence of non-genetic factors viz., location (agroclimatic zones), period and season of calving, and parity on TDMYs, TMY and 305MY were assessed, and the variance and covariance components for genetic parameters (heritability and genetic correlation) of the traits were estimated by the method of restricted maximum likelihood (REML) under a multivariate animal model and by a random regression model (RRM). The overall means of various TDMYs ranged from 4.98 (TDMY10) to 9.95 kg (TDMY2), and for TMY and 305MY, the means were 2480.33 and 2393.71 kg, respectively. The heritabilities estimated by the multivariate animal model for TDMYs were moderate and ranged from 0.26 ± 0.02 to 0.37 ± 0.02 and the estimates were less variable throughout lactation, while the estimates obtained by RRM were medium to high and ranged between 0.29 ± 0.01 and 0.67 ± 0.02 for milk yield on day 5 to 305 (DIM 5-DIM 305). The heritabilities estimated for TMY and 305MY were 0.43 ± 0.02 and 0.43 ± 0.02, respectively. The estimates of heritability for mid-lactation yields were comparatively less than those at the beginning and the end of lactation. The moderate to high estimates of heritabilities for TDMYs, TMY, and 305MY obtained in the present study offer ample scope for improving milk production through selective breeding. Genetic correlations between TDMYs estimated by the multivariate animal model were positive and high, with a range between 0.75 ± 0.03 and 0.99 ± 0.00. Considerably higher estimates (0.98-0.99) were observed between adjacent TDMYs showing strong genetic associations. By RRM, genetic correlations estimated between DIMs were positive (except for DIM 5 with DIM 125 to DIM 185 and DIM 125 with DIM 305), and the magnitude of genetic correlation decreased with an increase in the interval between the DIMs. The high genetic correlation observed between the TDMYs (in the early stage of lactation) and total lactation milk yield suggested that these test-day yields could be used favorably for the early selection of cows for milk production, which facilitates reduction in the generation interval and consequently increases the annual genetic gain for the milk production traits.

Allomilk: An Anthropogeny-Based Framework for Human Milk as a Climate Solution.

Climate change is an urgent threat to perinatal and infant health, with the greatest effects of climate change exposures being felt disproportionately by global majority communities who have been most harmed by systems of oppression. Human milk feeding is one recognized solution to bolster climate resilience. Yet, policies and practices to support human milk as a climate solution are inconsistent and under-prioritized, which is unsurprising given the lack of alignment between human history and current cultural context with regard to lactation and human milk access. This paper presents a new framework on lactation as a climate solution, which is unique in its incorporation of the critical history of cooperative breastfeeding in our species. Rooted in anthropogeny, or the study of human origins, and antiracist principles of lactation, the Allomilk Framework highlights five concepts of the ideal application of human milk as a climate solution, bridging ancient allonursing with present-day lactation and human milk access. These ideal applications-and the proposed development of measures to operationalize them-will advance the field through a shared understanding of the qualities that should be prioritized in the assessment of policies and practices at the intersection of climate resilience and human milk access. Application of the Allomilk Framework to assess and design future policies and practices will advance the field by increasing the potential for climate resilience and climate mitigation while working with-rather than against-the importance of cooperative breastfeeding in human history.

Milk production and viability of the various smallholder dairying models used in Zimbabwe.

An evaluation of milk yield, dairy products and viability of the smallholder dairy production models used in Zimbabwe was carried out. We used secondary data on 1167 smallholder dairy farmers. These were categorised into commercial dairying (119), Milk collection centre (MCC) bulking and processing (145), MCC bulking and delivering to processor (87), farm gate (468) and other (348) models. Data were analysed using SPSS version 25.0. The average daily milk yield per cows was highest in the Commercial dairying model (9.20 ± 0.4l) but was not significantly different from the MCC bulking and processing and MCC bulking and delivering to processor models. Average lactation milk yield per cow was highest (P < 0.05) in the commercial dairying model (2804.91 ± 133.9l) and was significantly different from the rest of the models. The processed milk products identified in the study were fermented milk, pasteurised milk and unspecified products but production volumes were very low in the respective models. There were no differences (P > 0.05) in gross margin across all the smallholder dairying models. The commercial dairying model surpassed all models on proportion of pure exotic dairy breeds, number of milking cows, milk yield. However, it was discovered that all models were underperforming but smallholder dairy farmers can be recommended to adopt the commercial dairying model if measures to improve milk yield per cow and reduce milk production costs are established.

Some Yield and Growth Traits of Anatolian Buffaloes and the Effects of First Calving Age and Calving Interval on These Traits

Numerous in-depth studies have described the fertility traits, growth performance and milk yield traits of dairy animals, which are considered indicators of welfare, but there are limited studies examining these traits within the framework of cause-effect relationships, especially in buffaloes. The aim of this study was to determine the changes in some milk, growth and fertility traits of Anatolian buffaloes over the years in some dairy farms where the Buffalo Breeding Project in Public Conditions was implemented in Samsun province and, to investigate the effects of first calving age (FCA) and calving interval (CI) on milk and growth traits. The study was conducted in 27 buffalo farms (3295 buffalo cows and 3317 buffalo calves) located in Bafra district, the region with the highest buffalo population in Samsun province, Türkiye. The data was taken from records previously kept within the scope of the relevant project. The data such as growth characteristics [birth weight (BW), 6th and 12th-mo live weight (LW) values of calves born between 2013-2020] and lactation traits of cows [lactation milk yield (LMY) and lactation duration (LD)] and FCA and CI values were analyzed by analysis of variance. The effect of years on LMY of buffalo cows was found to be significant, and significant positive changes were determined from year to year. In addition, the BW, 6th-mo, and 12th-mo LW values of calves also varied from year to year. As the FCA value of buffaloes increased, the BW, 6th-mo, and 12th-mo LW values of calves and LMY of cows increased. Similarly, CI values affected the BW values of calves (P&lt;0.01), and LMY and LD values increased in parallel with the increase in CI values. Consequently, determining the lactation and growth traits of buffaloes could benefit developing herd management practices that would optimize these performance indicators.

Supplementation of isoacids to lactating dairy cows fed low or high forage diets: Effects on performance, digestibility, and milk fatty acid profile

Our objective was to determine the effects of isoacids (ISO) on the lactation performance, digestibility, and milk fatty acid (FA) profile of Holstein cows fed 2 forage NDF levels (FL). The study was 10-wk long (including 2-wk for covariate) utilizing a randomized complete block design. Sixty-four mid-lactating Holstein cows [662 ± 71 kg BW, 119 ± 51 DIM, 2 ± 0.9 parity] were blocked by parity, DIM, and prior milk yield (MY) for multiparous cows or genetic merit for primiparous cows, and randomly assigned to 1 of the 4 diets (n = 16). Diets were arranged as a 2 × 2 factorial, with 2 FL containing 21 (HF) and 17% forage NDF (LF) without (WIA) or with ISO supplementation (IA, 7.85 mmol/kg DM and 3.44 mmol/kg DM for isobutyrate and 2-methylbutyrate, respectively). Diets were balanced for similar NEL (1.58 Mcal/kg DM), CP (16.0%) and total NDF (27.2%). Feed intake and MY were recorded daily. Nutrient digestibility for each cow was determined using indigestible NDF as a marker, and fecal samples were collected at 8-time points (4 h intervals between samples). Individual cow milk samples composited over a 10-wk period were analyzed using gas chromatography for FA profile. The statistical model included FL, ISO, and FL × ISO as fixed effects and block as a random effect (lme4 in R). The ISO did not affect DMI (P = 0.13), while LF had greater DMI than HF diets (27.8 vs. 26.0 kg/d; P < 0.01). However, ISO increased MY (34.7 vs. 37.2 kg/d; P < 0.01) and ECM (41.9 vs. 39.0 kg/d; P < 0.01) by 7% in HF but not in the LF diet, suggesting FL × ISO interaction (P = 0.04). Interestingly, ISO increased ADG (0.4 kg/d) but decreased MUN by 9% only in LF diet as indicated by FL × ISO interaction (P < 0.01). Additionally, ISO increased DM, OM, NDF, and CP digestibility by 10-24% in HF (P < 0.01), but not in LF (FL × ISO; P > 0.05). As expected, ISO increased milk odd chain FA profiles in the IA groups irrespective of FL, e.g., the IA had greater C15:0 (1.87 vs. 1.54 g/100g FA; P = 0.03) and a tendency to be greater C17:0 levels (0.86 vs. 0.76 g/100g FA; P = 0.05) compared with WIA groups. Overall, ISO improved MY and nutrient digestibility in the HF whereas it increased ADG and decreased MUN in LF diet. Additionally, ISO increased milk odd chain FA (C15:0 and C17:0) regardless of FL.

Strong associations between the FGF-2 gene and productivity traits of Holstein-Friesian dairy cattle

Sustainability in dairy cattle farms depends on the efficiency of milk yield and reproductive traits. Thus, this study aimed to investigate the effect of the FGF-2/Csp6I gene and major environmental factors on these traits in Holstein-Friesian cattle. A total of 212 whole blood samples were collected from the Vena coccygea of cattle and the data obtained from these samples were used in all statistical analyses. Then, the restriction fragment length polymorphism (RFLP) method (determination of genotypes) was conducted and programs including PopGene (allele and genotype frequencies), Minitab (association analyses) and MTDFREML (variance components and genetic parameters) were used. Alleles A (0.4269) and G (0.5731) as well as genotypes AA (0.174), AG (0.505) and GG (0.321) were found, indicating that the population is polymorphic and in Hardy-Weinberg equilibrium (P > 0.05). The effect of the Csp6I polymorphism of FGF-2 gene on peak milk yield (PMY) (P < 0.01); lactation milk yield (LMY), milking time (MT), 305-day and 200-day lactation milk yield (LMY305 and LMY200), average daily milk yield (ADMY) (P < 0.05); 100-day lactation milk yield (LMY100), age of using in first breeding (AUFB) and number of inseminations per conception (NIPC) (P < 0.10) were significant. The heritability of milk yield traits and the correlation between direct and maternal heritability for reproductive traits were high. Furthermore, the breeding value of PMY was higher for the AA genotype (0.745 ± 0.292) than for the AG genotype (−0.268 ± 0.171) (P < 0.05). As a result, the A allele and AA genotype for the FGF-2/Csp6I gene had an increasing effect on milk yield without compromising reproductive performance in Holstein-Friesian dairy cattle.

Principal component regression analysis to predict lifetime milk yield of Jaffarabadi buffaloes

The study aims to devise most appropriate prediction model for lifetime milk production of Jaffarabadi Buffalo, based on principal components formulated on initially expressed lactation records as predictors. Lactation milk yield, lactation period and peak milk yield records of first, second and third lactations of animals under study were used of 24 years (1987 to 2010). Principal components (PCs) were derived from data set using principal component regression analysis (PCRA), the principal components were used as predictors for predicting lifetime milk yield (LTMY). Multiple linear regression models were fitted to identify the best fitted model for prediction of lifetime milk yield with the first principal component to all principal component as a predictor. The equation LTMY = 7825.8768+2.8118 (PC1) - 13.7098 (PC2) - 599.0908 (PC3) + 3.0266 (PC4) - 8.8196 (PC5) - 257.9315 (PC6) + 2.6042 (PC7) explained 98.9% variation in the estimated values with adjusted R2= 59.09% variation in the estimated values. The curve estimation analysis showing the appropriateness of first seven principal components as predictor was the most appropriate model for lifetime milk yield. These prediction equations may be helpful in selection at an early stage of Jaffarabadi Buffalo based on early part lactation records.

Effect of automated health monitoring based on rumination, activity, and milk yield alerts versus visual observation on herd health monitoring and performance outcomes

A primary objective of this randomized trial was to compare the percentage of cows that underwent clinical examination and were diagnosed with clinical health disorders (CHD) with a health monitoring program that relied only on automated monitoring system alerts vs a program that relied only on visual observation of clinical signs of disease to select cows for clinical examination. Another objective was to compare the effects of these health monitoring programs on milk yield, the herd exit dynamics (i.e., cows sold and dead), and first service reproductive outcomes. Lactating Holstein cows (n = 1,204) enrolled in the experiment were fitted with a neck-attached sensor of an automated monitoring system (HR Tags; Merck & Co., Inc.) that generated health alerts based on rumination time and activity. Milk yield was monitored 3 times per day by automated milk meters (MM27BC, DeLaval). Cows were blocked by parity, close-up period diet, and stratified by previous lactation milk yield, and then were randomly assigned within block to different programs for monitoring health from 3 to 21 d in milk (DIM). Cows in the visual observation group (VO; n = 597) were selected for clinical examination exclusively based on visual observation of clinical signs of disease, whereas cows in the automated health monitoring group (AHM; n = 607) were selected for clinical examination based on health alerts consisting of the following: a Health Index Score < 86 arbitrary units, daily rumination < 250 min, or a reduction of > 20% in daily milk yield. Once selected for examination, the clinical exam was the same for both treatment groups. Binary data such as the occurrence of CHD, herd exit, and pregnancies per AI were analyzed with logistic regression. Daily and weekly milk yield were analyzed using ANOVA with repeated measurements. More cows underwent a clinical examination, more cows were diagnosed with at least one CHD, and more cows received treatment in the AHM than the VO treatment group. Cows in the AHM treatment had more accumulated milk than cows in the VO treatment from 2 to 21 DIM. Cows in the AHM treatment diagnosed with at least one CHD produced more milk from 3 to 18 and 20 to 21 DIM than cows diagnosed with a CHD in the VO treatment. Fewer cows left the herd up to 21 DIM for the AHM than the VO treatment. Pregnancies per AI at first service were greater for the VO than the AHM treatment at 30 d but not at 50 d after AI and no difference in pregnancy loss was detected. In conclusion, a health monitoring strategy that used automated health alerts increased the risk of undergoing clinical examination and having CHD diagnosed compared with a program that selected cows for clinical examination based exclusively on visual observation. Cows monitored with the program that relied on automated alerts also had greater milk yield in the first 21 DIM. Thus, monitoring cow health based on automated behavior and milk yield alerts might be a more effective alternative for health monitoring than exclusive use of visual observation of clinical signs of disease.

The composition of early lactation milk in recipient dairy cows determines success in bovine embryo transfer.

To identify new criteria for selecting recipient dairy cows for embryo transfer (ET), we retrospectively examined the effects of the composition of early lactation milk on fertility risk in ET. This study investigated the association between milk fat (FAT), milk protein (PRO), and milk urea nitrogen (MUN) levels during early lactation, based on production records, and subsequent fertility risk in ET using contingency table analysis and multivariable logistic regression analysis, which included five confounding variables. The results showed that MUN levels during early lactation were negatively associated with fertility risk in ET, while FAT and PRO levels showed no clear association. A reduction in MUN levels during the peak lactation period suggests a deficiency in dry matter intake, an inadequate protein supply, and an imbalance in the ratio of proteins to fermentable carbohydrates in the rumen, which may have adversely impacted fertility risk in ET.Monitoring MUN levels is crucial for maintaining a proper protein balance. The results obtained in this study suggest that MUN levels in the early lactation phase obtained from production records can be used as a predictor of fertility in recipients to improve the fertility risk in ET. No special techniques or costs are required for using production records, making them easy to use in clinical practice. Our findings provide valuable insights for optimizing cost-effectiveness and fertility risk in ET and their clinical applications.

Whole-genome sequencing of bacteria accountable for lactational mastitis in humans combined with an examination of their antibiotic resistance profiles.

Lactational mastitis, a common condition affecting nursing mothers, is characterized by mammary gland inflammation during lactation. This inflammatory response typically occurs due to bacterial infection. The discomfort and pain associated with lactational mastitis can significantly impact a mother's ability to breastfeed comfortably and may lead to the cessation of breastfeeding altogether if left untreated. Antibiotics are commonly prescribed to target the bacteria causing the infection and alleviate symptoms, aiming to treat the infection. Nevertheless, a notable worry linked to antibiotic use is the emergence of antibiotic resistance, compounded by the possible persistence of antibiotics in milk. Additionally, lactational mastitis is characterized by its polymicrobial nature. In this study, bacteria were isolated from infected breast milk samples and whole-genome sequencing was performed on eleven isolates to accurately identify the bacteria and assess their antibiotic resistance profiles. Using Galaxy tools and the ResFinder database, we identified Bacillus paraanthracis, Bacillus altitudinis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Alcaligenes faecalis, and Bacillus licheniformis, along with antibiotic-resistant genes like fosB1, cat86, erm (D), blaZ, and mdf (A). ABRicate aided in antimicrobial resistance (AMR) gene analysis, and CARD visualized their distribution. Our study demonstrates that the severity of infection is directly proportional to an increase in somatic cell count (SCC). This research sheds light on microbial diversity in lactational mastitis milk and provides crucial insights into antibiotic-resistance genes. Utilizing bioinformatics tools, such as those employed in this study, can inform the design of effective treatment strategies for lactational mastitis infections.

Comparative study of first lactation performance of Norwegian Red crossbred cows with traditional breeds in New Zealand dairy systems

ABSTRACT Some New Zealand dairy farmers are using semen from Norwegian Red (NR) bulls to explore the performance of this breed under local grazing conditions. The objective of this study was to compare the first lactation performance of first cross NR cattle with traditional New Zealand breeds. Data were collected from six dairy farms in Southland, New Zealand, during 2022–2023 milk production seasons. Data were collected from 1178 first lactation cows including herd test of daily yields of milk, fat and protein and somatic cell counts, and persistency. Breeds included 386 NR cross (NRX), 231 Holstein Friesian (F), 84 Holstein Friesian cross (FX), 134 Holstein Friesian x Jersey (FJ) and 58 Jersey cross (JX) cows. Findings indicate F cows produced the greatest cumulative milk yield (3,744 kg), 138.6 kg more than NRX cows. There were no significant differences among the breed groups for milk yield and milk solids yield persistency and SCS (SCS = Log2 SCC). The total lactation milk yield of NRX cows was lower than that of the other breeds, excluding JX. These results pertain specifically to first lactation cows; therefore, it is necessary to undertake further analysis to evaluate the long-term productivity and longevity of NR breeds under New Zealand conditions.

Variation in bovine milk stability according to lactational stage and genetic group.

We address the hypothesis that at early and late lactation milk presents low ethanol stability due to high acidity and ionic calcium values. Our aim was to evaluate the functional traits of milk (milk ethanol stability: MES, acidity and ionic calcium: iCa) according to lactation stage in different genetic groups. Raw milk samples were collected from Jersey (n = 271), Holstein (n = 248) and Jersey × Holstein crossbred cows (n = 82), raised on five commercial farms located in the state of Paraná, Brazil. Milk composition, somatic cell count (SCC), milk urea nitrogen (MUN), MES, pH, acidity and iCa were determined. Days in milk (DIM) were categorized into four classes: 1-60, 61-150, 151-305 and over 305 DIM. Data were submitted to analysis of variance. Fixed and random effects were incorporated into the model, in a repeated measures in time arrangement using the mixed models methodology. Significant interactions between DIM class and genetic groups were detected. The comparison between each combination of genetic group and DIM class showed that at the beginning of lactation, Holsteins produced milk with higher MES than Jersey and crossbreds. At 105-305 DIM Holstein milk presented higher MES than Jersey, while beyond 305 DIM Holstein milk showed higher MES than crossbred cows. At the beginning of lactation acidity was higher in Holstein milk and crossbreds compared with Jersey, while acidity was lower in Holstein milk compared with Jersey and crossbreds in the other lactation stages. Ionic calcium was highest after lactation peak for Holstein, but did not vary between lactation stages for Jersey and crossbreds. Functional characteristics of bovine raw milk such as MES, iCa and acidity varied between lactation stages in a distinct manner according to genetic groups. Early and end lactation stages are challenging in terms of low stability, especially for Jersey and crossbreds.

Effect of Exogenous Melatonin on Performance and Mastitis in Dairy Cows.

Mastitis is an important factor affecting the health of cows that leads to elevated somatic cell counts in milk, which can seriously affect milk quality and result in huge economic losses for the livestock industry. Therefore, the aim of this trial was to investigate the effect of melatonin on performance and mastitis in dairy cows. Forty-eight Holstein cows with a similar body weight (470 ± 10 kg), parity (2.75 ± 1.23), number of lactation days (143 ± 43 days), BCS (3.0-3.5), milk yield (36.80 ± 4.18 kg), and somatic cell count (300,000-500,000 cells/mL) were selected and randomly divided into four groups: control (CON group), trial Ⅰ (T80 group), trial Ⅱ (T120 group), and trial Ⅲ (T160 group). Twelve cows in trial groups I, II, and III were pre-dispensed 80, 120, and 160 mg of melatonin in edible glutinous rice capsules along with the basal ration, respectively, while the control group was fed an empty glutinous rice capsule along with the ration. The trial period was 37 days, which included a 7-day adaptive phase followed by a 30-day experimental period. At the end of the trial period, feeding was ended and the cows were observed for 7 days. Milk samples were collected on days 0, 7, 14, 21, 28, and 37 to determine the somatic cell number and milk composition. Blood samples were collected on days 0, 15, 30, and 37 of the trial to determine the serum biochemical indicators, antioxidant and immune indicators, and the amount of melatonin in the blood. The results showed that the somatic cell counts of lactating cows in the CON group were lower than those in the T120 group on days 14 (p < 0.05) and 28 (p < 0.01) at 1 week after melatonin cessation. The milk protein percentage and milk fat percentage of cows in the T120 group were higher than those in the CON group (p < 0.01). The total protein and globulin content in the T120 group were higher than those in the CON group (p < 0.01). In terms of antioxidant capacity and immunity, the cows 1 week after melatonin cessation showed higher superoxide dismutase activity and interleukin-10 contents (p < 0.01) compared with the CON group and lower malondialdehyde and tumor necrosis factor-alpha contents (p < 0.01) compared with the T120 group. The melatonin content in the T120 group was increased relative to that in the other groups. In conclusion, exogenous melatonin can increase the content of milk components, reduce the somatic cell count, and improve the antioxidant capacity and immune responses to a certain extent. Under the experimental conditions, 120 mg/day melatonin is recommended for mid- to late-lactation cows.

Social interactions of dairy cows and their association with milk yield and somatic cell count

The social environment experienced by livestock can have implications for their health, welfare, and subsequently, their productivity. Changes in the dairy industry have led to larger herd sizes and altered management of cows, which has impacted their social environment. Studies have shown that mixing of animals can lead to social instability of groups and expansion of herds can lead to high stocking densities resulting in social stress and negative effects on production. Yet few studies have assessed the putative impact of positive cow-cow interactions, such as proximity to preferred herd mates and engaging in grooming, on milk production and udder health. To address this, we used cattle proximity as a proxy for affiliative interactions between cows in three dairy herds in south-west England over one week study periods. We created proximity networks of dairy cows and measured cow-cow associations according to milk yield, somatic cell count (SCC; an indicator of mastitis), parity (number of lactations in the cow’s lifetime), and lactation stage (grouped by days in milk for current lactation). We then assessed associations between social factors and production and health measures (milk yield and SCC). In all three herds, cows interacted more with cows in the same parity, suggesting early social bonding may be evident later in life and that grouping animals in terms of parity might encourage affiliative interactions. Cows did not associate according to milk yield, SCC, or lactation stage. There was no significant association between milk production or SCC and the total time spent in social contact with other cows, the mean time spent with the four closest herd mates, or the number of closest herd mates of the same parity. We suggest that further research on positive social environments for dairy cattle is warranted in the interests of improving welfare and enabling a more robust assessment of the putative effects on production and health parameters

Genetic and Phenotypic Trends for Production and Reproduction Traits in Murrah Buffaloes.

The objective of the study was to estimate genetic and phenotypic trends for first lactation production and reproduction traits in Murrah buffaloes. The information of pedigree and targeted traits of 640 Murrah buffaloes was collected for the period from 1997 to 2020. The first lactation production traits included first lactation milk yield (FLMY), 305 days first lactation milk yield (305FLMY), first lactation length (FLL), first lactation peak yield (FPY) whereas reproduction traits included first service period (FSP), first calving interval (FCI) and first dry period (FDP). Genetic and phenotypic trends were estimated. Phenotypic trends for FLMY, 305FLMY, FLL and FPY exhibited as 36.96 ± 8.58 kg/year, 31.93 ± 8.34 kg/year, 1.47 ± 0.55 days/year and 0.12 ± 0.02 kg/year, respectively and respective genetic trends exhibited as 3.73 ± 1.67 kg/year, 1.94 ± 0.76 kg/year, -0.15 ± 0.07 days/year and 0.01 ± 0.01 kg/year, respectively. It was revealed that there were significant (p < 0.05) and positive phenotypic trends for all production traits while genetic trends were significant (p < 0.05) for FLMY and 305FLMY traits. The phenotypic trends of studied reproductive traits indicated that only FDP trait significantly (p < 0.01) decreased (1.87 days/year) over time. For FSP and FCI traits, nonsignificant (p > 0.05) genetic and phenotypic trends indicated no change over time. This study highlighted potential challenges in maintaining reproductive efficiency alongside productivity improvements in Murrah buffaloes.

Influence of non-genetic factors on milk production traits of Gangatiri cattle in Varanasi district of Uttar Pradesh

Research was carried out to examine the influence of non-genetic factors on the milk production characteristics of Gangatiri cows. The study was analyzed from 1254 Gangatiri cows across three tehsils (Pindra, Rajatalab, and Sadar) in Varanasi, Uttar Pradesh. The objective was to ascertain the effects of a number of variables on lactation duration, daily milk production, and lactation milk production including the area, calving season, farmer's economic background, parity, and age at first calving. The overall average means for lactation milk production, daily production of milk, and lactation period were discovered to be 794.6413 kg, 3.956 kg, and 203.8327 days, respectively. The comparison of different parameters indicated that non-genetic factors had a significant impact on milk production. These factors include the region where the survey was conducted, the calving season, the financial context of the farmer, parity or lactation, and first calving age. By analyzing the mean of these parameters, we could determine their impact on milk yield potentials. Given the influence of external variables and differences in the qualities under investigation, the study indicates that significant improvements in the population of Gangatiri cattle can be accomplished by improved management.

Effect of prolactin concentration during the dry period on the subsequent milk production of dairy cows

Shortening the dry period has a negative impact on milk production of the following lactation. One possible explanation is that a period of low prolactin (PRL) concentration is necessary to restore mammary gland milk production capacity. Therefore, the objective of this study was to determine the effect of lowering blood PRL level on subsequent lactation milk production. In this experiment, quinagolide was used to inhibit PRL secretion during the dry period. Thirty Holstein cows were randomly assigned one of 3 dry period managements: a conventional (60 d) dry period (CD) and 2 short (35 d) dry period treatments (SD). Short dry period cows received either water (SDwater) or quinagolide (2 mg, SDquin) injections twice daily from dry-off until 14 d before calving. Cows were followed during the first 20 wks of the subsequent lactation. When CD cows were dry but SD cows were lactating, concentration of PRL was lower in the CD cows than in the SD cows. During the injection period, PRL of SDquin cows was lower than that of the other treatments and was greater in the blood of SDwater than in that of CD cows. After the injection period until calving, no difference in PRL concentration was observed between treatments. After calving, PRL concentration of the SDquin cows was greater than those of CD and SDwater cows. During the first 20 wks of lactation, energy corrected milk (ECM) was lower in SDwater cows than in CD and SDquin cows. The ECM of the latter groups were not different. During the same period, mammary expression of genes related to milk synthesis, pro-apoptotic genes, as well as the expression of the short and long isoforms of the PRLR genes were not affected; however, the expression of SOCS3 gene tended to be lower for the SDquin than the SDwater cows. Lowering the PRL level during short dry period restored milk production to the level normally observed after a conventional dry period, which suggests that higher PRL levels during short dry period are the cause of the lower milk production after a short dry period. Ultimately, strategies to lower blood PRL level may help the adoption of short dry period.

Essential oils and capsaicin in the diet of Jersey cows at early lactation and their positive impact on anti-inflammatory, antioxidant and immunological responses.

The objective of this work was to determine whether the addition of phytogenic compounds based on essential oils (carvacrol, eugenol, cinnamaldehyde) and resinous pepper oil (capsaicin) to the diet of Jersey cows at the beginning of lactation affects anti-inflammatory, antioxidant and immunomodulatory responses, as well as whether there are effects of EO on blood metabolites, ruminal fermentation, digestibility and milk production and composition. Six primiparous cows (370.00 ± 17kg body weight (BW); 13.02kg dry matter intake (DMI); 21 days of lactation and average milk production of 20 ± 2L per day) were allocated to crossed experimental design (2 × 2) with two experimental periods of 28 days and two treatments. Blood, milk and rumen fluid were collected and, at the end of each period, feed and feces samples were collected to evaluate the apparent digestibility of nutrients. The groups were control (CLT) without supplementation and treated (BEO) with the addition of 150mg/kg of dry matter of the phytogenic to the concentrated portion of the diet. Cows in the BEO group had lower numbers of leukocytes (P ≤ 0.05) and lymphocytes (P ≤ 0.02), but total protein and globulin levels were higher on days 21 and 28 (P ≤ 0.01). In the BEO group, the levels of immunoglobulin A, immunoglobulin heavy chain and transferrin were higher (P ≤ 0.05). The levels of ceruloplasmin, haptoglobin and C-reactive protein were lower in the BEO group (P ≤ 0.05). Lipid peroxidation levels and protein carbonyl content were lower in the BEO group. The total antioxidant capacity (P ≤ 0.09) and the activity of glutathione S-transferase (P ≤ 0.03) and glutathione peroxidase (P ≤ 0.05) were higher in the BEO group. Cows in the BEO group had lower pH (P ≤ 0.05), acetic acid concentrations (P ≤ 0.01) and higher protozoa counts (P ≤ 0.01). Our results suggest that phytogenic supplementation has positive effects on the health of Jersey cows in early lactation, characterized by immunostimulant, antioxidant and anti-inflammatory effects.