Lactation Milk Research Articles

Haplotype-based association study of production and reproduction traits in multigenerational Vrindavani population

Haplotype-based association analysis promises to reveal important information regarding the effect of genetic variants on economic traits of interest. The present study aimed to evaluate the haplotype structure of Vrindavani cattle and explore the association of haplotypes with (re)production traits of economic interest. Genotyping array data of medium density (Bovine50KSNP BeadChip) on 96 randomly selected Vrindavani cows was used in the present study. Genotypes were called in GenomeStudio program while quality control was undertaken in PLINK using standard thresholds. The phenotypic traits used in the present study included age at first calving, dry days, lactation length, peak yield, total lactation milk yield, inter-calving period and service period. The haplotype structure of Vrindavani population was assessed, using a sliding window of 20 SNP with a shift of 5 SNPs at a time, in terms of the size of haplotype blocks regarding their length (in Kb) and frequency in chromosome-wise fashion. Haplotype blocks were assessed for possible association with important production and reproduction traits across three lactation cycles in Vrindavani cattle population. The first ten principal components were included in the model for haplotype-based association analysis to correct for stratification effects of assessed individuals. Multiple haplotypes were found to be associated with age at first calving, total lactation milk yield, peak yield, dry days, inter-calving period and service period. Various candidate genes were found to overlap haplotypes that were significantly associated with age at first calving (CDH18, MARCHF11, MYO10, FBXL7), total lactation milk yield (TGF, PDE1A, and COL8A1), peak yield (PPARGC1A, RCAN1, KCNE1, SMIM34 and MRPS6), dry days (CPNE4, ACAD11 and MRAS), inter-calving period (ABCG5, ABCG8 and COX7A2L) and service period (FOXL2 and PIK3CB). The putative candidate genes overlapping the significantly associated haplotypes revealed important pathways affecting the production and reproduction performance of animals. The identified genes and pathways may serve as good candidate markers to select animals for improved production and reproduction performance in future generations.

Providing Lactation Care Following Stillbirth, Neonatal and Infant Death: Learning from Bereaved Parents

Objective: The study aimed to identify how, from the perspective of bereaved parents, hospital-based health professionals can better meet their lactation care needs. Methods: In-depth interviews were conducted with 17 mothers and 7 fathers bereaved by stillbirth, neonatal death, or older infant death. Participants were recruited from three large hospitals in Eastern Australia including two with human milk banks. Qualitative thematic data analysis identified bereaved parents' lactation experiences, needs, and how parents wanted lactation care to be provided. Results: Participants experienced lactation after infant death as hard and challenging, while at the same time they received limited lactation care. The negative impact of lactation, however, could be mediated by anticipatory guidance, assistance to make sense of lactation, support to make decisions from available lactation and breast milk management options, and support with breast care for as long as required. Bereaved parents explained lactation care was best provided by health professionals they had come to know and trust rather than by a particular professional role. Care should be provided with compassion, in a manner respectful of individual circumstances, inclusive of partners, and supplemented by quality written information. When bereaved parents felt supported to manage their lactation in a manner consistent with their unique needs, lactation for some could have a positive impact on grief. Conclusion: Bereaved parents have demonstrated that comprehensive lactation care is critical to their health and well-being. Such care should be more fully incorporated into hospital-based bereavement care policies and practices.

Genetic evaluation of Frieswal cattle for first lactation milk yield from smallholder dairy production systems in Kerala, India

The present investigation was undertaken to determine the genetic worth of Frieswal (62.5% HF × 37.5% Sahiwal) young bulls through progeny testing under field conditions in Kerala state, India. A total of 65 Frieswal bulls were evaluated based on 1037 first lactation records of their daughters calved over a period of 15 years from 1995 to 2010 were used for the study. The overall average breeding value for the first lactation 305-days milk yield was estimated as 2229.19±50.91 kg with a range of 2193.74±66.59 to 2280.62±66.59 kg. Out of 65 bulls inducted in 7 different sets, 33 bulls (50.7%) had breeding values higher than the herd average (2229.19 kg). The number of daughters per bull varied from 7 to 51 whereas the average number of daughters per bull was 16. The genetic superiority and percentage genetic superiority of the top 25 bulls (38.46%) over population ranged from 6.26 to 51.43 and 0.28 to 2.30, respectively. The least squares analysis of variance revealed that the year of calving had a significant effect on the first lactation milk yield of daughters. The increasing trend of first lactation milk yield over year / bull set observed in the present study indicates the successful implementation of large-scale progeny testing programme under field conditions.

Type 2 abomasal ulceration in cattle and buffalo: energy and lipid metabolic status, clinico-biochemical parameters, treatment, and prognostic indicators

Twenty nine animals (22 cattle and 7 buffaloes) having type 2 abomasal ulcer (AU2) were studied in this prospective investigation, along with a control group (n = 20). Signalment, history, clinical signs, and laboratory alterations were determined. Blood, rumen fluid, abomasal fluid, and fecal samples were collected at the time of presentation. Depressed behavior, anorexia, dehydration, melena, sparse feces, and mushy rumen with substantially reduced or nonexistent motility, tachycardia, and tachypnea were common clinical findings. Colic was observed in 58% of animals. While the neutrophil count was significantly greater, the mean of lymphocytes, hemoglobin, erythrocyte count, and hematocrit were all lower (p < 0.05) than the corresponding control values. In comparison to the control values, the levels of BHBA, NEFA, lactate, bilirubin, BUN, creatinine, LDH, CK, GGT, ALP, and AST were significantly higher but levels of proteins, cholesterol, Na, K, Cl, and calcium were lower (p < 0.05). In comparison to the control values, the other hemato-biochemical parameters did not differ substantially (p < 0.05). The rumen and abomasal pH were within the reference range while rumen chloride concentration was increased in majority of animals. Higher percentage (p < 0.05) of non-survivors showed left shift and toxic alterations in neutrophils than the survivors. As compared to the survivors, the non-survivors had higher (p < 0.05) BHBA, triglycerides, total bilirubin, AST, ALP, LDH, and lactate, and lower (p < 0.05) fibrinogen and calcium. The response to medical treatment was fair, long time survival rate was good, and there was no recurrence. The follow-up period was 28months. After treatment, both the current and the subsequent lactation's milk production were unaffected.

A randomized study on the effect of extended voluntary waiting period in primiparous dairy cows on milk yield during first and second lactation

Extending the voluntary waiting period (VWP) for primiparous cows can have a positive impact on fertility without a negative impact on milk production per day in the calving interval (CInt). We investigated the effect of extended VWP during first lactation on milk yield (MY) during 2 consecutive lactations in primiparous cows. The study involved 16 commercial herds in southern Sweden. A total of 533 Holstein and Red dairy cattle (Swedish Red, Danish Red, Ayrshire) dairy cows were randomly assigned to a conventional 25 to 95 d VWP (n = 252) or extended 145 to 215 d VWP (n = 281). Data on calvings, inseminations, and test-day yields were retrieved from the Swedish Milk Recording System. Cows with VWP according to plan and completing 1 or 2 CInt with a second or third calving were included in the data analysis. Whole lactation and 305-d energy-corrected milk (ECM) yield were higher for the extended VWP group than the conventional VWP group in both the first lactation (12,307 vs. 9,587 and 9,653 vs. 9,127 kg ECM) and second lactation (12,817 vs. 11,986 and 11,957 vs. 11,304 kg ECM). We found no difference between the VWP groups in MY per day during the first CInt or during the first and second CInt combined, although MY per day during the second CInt was around 1.5 kg higher for cows with extended VWP than for cows with conventional VWP. Thus extended VWP for primiparous cows can be used as a management tool without compromising MY.

Patterns of Fourier-transform infrared estimated milk constituents in early lactation Holstein cows on a single New York State dairy

Cows undergo immense physiological stress to produce milk during early lactation. Monitoring early lactation milk through Fourier-transform infrared (FTIR) spectroscopy might offer an understanding of which cows transition successfully. Daily patterns of milk constituents in early lactation have yet to be reported continuously, and the study objective was to initially describe these patterns for cows of varying parity groups from 3 through 10 d postpartum, piloted on a single dairy. We enrolled 1,024 Holstein cows from a commercial dairy farm in Cayuga County, New York, in an observational study, with a total of 306 parity 1 cows, 274 parity 2 cows, and 444 parity ≥3 cows. Cows were sampled once daily, Monday through Friday, via proportional milk samplers, and milk was stored at 4°C until analysis using FTIR. Estimated constituents included anhydrous lactose, true protein, and fat (g/100 g of milk); relative % (rel%) of total fatty acids (FA) and concentration (g/100 g of milk) of de novo, mixed, and preformed FA; individual fatty acids C16:0, C18:0, and C18:1 cis-9 (g/100 g of milk); milk urea nitrogen (MUN; mg/100 g of milk); and milk acetone (mACE), milk β-hydroxybutyrate (mBHB), and milk-predicted blood nonesterified fatty acids (mpbNEFA) (all expressed in mmol/L). Differences between parity groups were assessed using repeated-measures ANOVA. Milk yield per milking differed over time between 3 and 10 DIM and averaged 8.7, 13.3, and 13.3 kg for parity 1, 2, and ≥3 cows, respectively. Parity differences were found for % anhydrous lactose, % fat, and preformed FA (g/100 g of milk). Parity differed across DIM for % true protein, de novo FA (rel% and g/100 g of milk), mixed FA (rel% and g/100 g of milk), preformed FA rel%, C16:0, C18:0, C18:1 cis-9, MUN, mACE, mBHB, and mpbNEFA. Parity 1 cows had less true protein and greater fat percentages than parity 2 and ≥3 cows (% true protein: 3.52, 3.76, 3.81; % fat: 5.55, 4.69, 4.95, for parity 1, 2, ≥3, respectively). De novo and mixed FA rel% were reduced and preformed FA rel% were increased in primiparous compared with parity 2 and ≥3 cows. The increase in preformed FA rel% in primiparous cows agreed with milk markers of energy deficit, such that mpbNEFA, mBHB, and mACE were greatest in parity 1 cows followed by parity ≥3 cows, with parity 2 cows having the lowest concentrations. When measuring milk constituents with FTIR, these results suggest it is critical to account for parity for the majority of estimated milk constituents. We acknowledge the limitation that this study was conducted on a single farm; however, if FTIR technology is to be used as a method of identifying cows maladapted to lactation, understanding variations in early lactation milk constituents is a crucial first step in the practical adoption of this technology.

Cellular proliferation and apoptosis in Staphylococcus aureus–infected heifer mammary glands experiencing rapid mammary gland growth

Intramammary infections in nonlactating mammary glands are common and can occur during periods of rapid mammary epithelial cell (MEC) accumulation, which may ultimately reduce total MEC numbers. Reduced MEC numbers, resulting from impaired MEC proliferation and increased cellular apoptosis, are expected to reduce future milk yields. The objective of this study was to measure the degree of cellular proliferation and apoptosis in the epithelial and stromal compartment of uninfected and Staphylococcus aureus-infected mammary glands hormonally induced to grow rapidly. Nonpregnant heifers (n = 8) between 11 and 14 mo of age were administered supraphysiological injections of estradiol and progesterone for 14 d. One mammary gland of each heifer was randomly selected and infused with Staph. aureus (CHALL) while another mammary gland was designated as an uninfected control on d 8 of injections. Mammary tissues were collected on the last day of hormonal injections from center and edge parenchymal regions and subject to proliferation assessment via Ki-67 staining and apoptotic assessment via terminal deoxynucleotidyl transferase dUTP nick-end labeling. Differences in cellular proliferation between CHALL and uninfected control quarters were not apparent, but proliferation of MEC was marginally greater in edge parenchyma than in center parenchyma. Coincidently, CHALL quarters experienced a greater percentage of apoptotic MEC and lower percentage of stromal cells undergoing apoptosis than uninfected control quarters. This study also provides the first insight into the mechanisms that allow the mammary fat pad to be replaced by expanding mammary epithelium as edge parenchyma contained a greater percentage of apoptotic stromal cells than center parenchyma. When taken together, these data suggest that Staph. aureus intramammary infection impairs mammary epithelial growth through reductions in MEC number and by preventing its expansion into the mammary fat pad. These factors during periods of rapid mammary growth are expected to impair first lactation milk yield.

Observational study on dry period length and its associations with milk production, culling risk, and fertility in Italian dairy farms

From an initial data set involving 84,189 lactations, this research evaluated the relationship between dry period length (DPL) and milk production, culling risk, and fertility. The data set included a total of 48,297 multiparous cow lactation records, with a calving event occurring in 2019 and 2020, belonging to 62 Italian herds with at least 150 cows. The DPL was classified into 5 categories (<40, 40-49, 50-60, 61-70, and >70 d) and these categories were used to establish the association between DPL and the outcome variables. All data obtained were assessed with simple and multiple linear regressions and Cox proportional hazard models. Cumulative milk production at 60 d in milk (DIM) was the highest in DPL categories of 61 to 70 d (2,480.29 kg/cow) and 50 to 60 d (2,474.39 kg/cow), and the lowest in <40 d (2,281.29 kg/cow). Similarly, DPL categories 61 to 70 d (10,830.94. kg/cow) and 50 to 60 d (10,817.48 kg/cow) had the highest 305-d milk production, whereas the <40 d (10,200.96 kg/cow) had the lowest one. The groups with a DPL of 40 to 49 d and >70 d had slightly, but significant, lower milk production both as cumulative 60 DIM and predicted 305-d milk production. Culling risk had a curvilinear behavior, with DPL <40 d and DPL >70 d showing significantly higher odds for culling during the first 60 DIM compared with DPL of 50 to 60 d [relative risk (RR): 1.53; RR: 1.46]. Within the same comparison, DPL of 61 to 70 d also had a slightly higher risk for culling (RR: 1.13). The DPL was associated also with fertility, with DPL of 40 to 49 d and 50 to 60 d having the greatest odds for pregnancy within the first 200 DIM. The DPL of <40, 61 to 70, and >70 d were negatively associated with fertility and showed pregnancy risks of 0.87, 0.95, and 0.94, respectively. This paper reinforces the importance of DPL as we demonstrated its association with milk production, culling, and fertility. Despite being attractive for high production dairy cows, very short dry periods are at the same time also associated with higher culling risk, lower milk production and fertility. Long DPL is detrimental, especially regarding culling and fertility. In summary, reducing variability in DPL and avoiding extremes by improving reproductive performance, maximizing late lactation milk production and making wise decisions on dry-off timing, may lead to better performances and lower early culling under Italian dairy conditions.

Medium chain fatty acid supplementation improves animal metabolic and immune status during the transition period: A study on dairy cattle.

The transition period is the stage of the high incidence of metabolic and infectious diseases in dairy cows. Improving transition dairy cows' health is crucial for the industry. This study aimed to determine the effects of dietary supplementation medium-chain fatty acids (MCFAs) on immune function, metabolic status, performance of transition dairy cows. Twenty multiparous Holstein cows randomly assigned to two treatments at 35 d before calving. 1) CON (fed the basal 2) MCFA treatment (basal diet was supplemented at an additional 20 g MCFAs mixture every day) until 70 d after calving. The results showed that the serum amyloid A myeloperoxidase concentrations in the blood of cows in MCFA treatment significantly decreased during the early lactation (from 1 d to 28 d after calving) 0.03, 0.04, respectively) compared with the CON, while the tumor necrosis factor concentration was significantly decreased at 56 d after calving (P = 0.02). In addition, the concentration of insulin in the pre-calving (from 21 d before calving to calving) blood of cows in MCFA treatment was significantly decreased (P = 0.04), and concentration of triglyceride also showed a downward trend at 28 d after calving 0.07). Meanwhile, MCFAs supplementation significantly decreased the concentrations of lithocholic acid, hyodeoxycholic acid, and hyocholic acid in the blood at 1 d calving (P = 0.02, < 0.01, < 0.01, respectively), and the level of hyocholic acid taurocholic acid concentrations (P < 0.01, = 0.01, respectively) decreased dramatically at 14 d after calving. However, compared with the CON, the pre-calving dry matter intake and the early lactation milk yield in MCFA treatment were significantly decreased (P = 0.05, 0.02, respectively). In conclusion, MCFAs supplementation transition diet could improve the immune function and metabolic status of dairy cows, and the health of transition cows might be beneficial from the endocrine status.

Reducing milking frequency from 3 to 2 times daily in early lactation: effects on milk production, health and body condition.

The objective of this experiment was to investigate the effect of reducing early lactation milking frequency on milk yield and persistency through lactation and early lactation fat mobilization, measured by body condition score (BCS) and BHB in milk. We hypothesized that milking cows twice per day in early lactation before milking them 3 times per day for the remaining lactation would cause less fat mobilization in early lactation, a lower peak milk yield but improved persistency throughout lactation compared with milking cows 3 times per day for the entire lactation. The experiment took place on 2 commercial dairy farms in Denmark. All cows calving in a period of nine months (n = 239) in their current first and later parities were randomly allocated at dry-off to 1 of 3 treatments based on expected calving date. The treatments were (1) cows milked 2 times per day for 1 week after calving, (2) cows milked 2 times per day for 4 weeks after calving and (3) cows milked 2 times per day for 7 weeks after calving. All cows were then milked 3 times per day for the remaining lactation. Milk yield peaked 3.3 and 3.6 d later and milk yield persistency improved with 18 and 19 g per day when cows were milked 2 times per day for 4 and 7 weeks, respectively, compared with milking 2 times per day for 1 week after calving. We found a significant highest milk BHB in treatment 2, but the underlying effect of milking cows 2 times per day for 4 weeks compared with 1 or 7 weeks was unclear. In conclusion, we did not confirm our hypothesis that milking cows 2 times per day compared to 3 times in early lactation would reduce fat mobilization and reduce peak yield. We did, however, find an improved milk yield persistency, which partially offset a numerical reduction in peak yield, and hence there was no significant effect of reducing early lactation milking frequency on total lactation (305 DIM) milk yield.

Determination of Direct and Indirect Effects on Milk Yield of Anatolian Buffaloes Using Path Analysis

This study aimed to determine the direct and indirect effects of the independent variables presented by the lactation lenght (LL), age of calving (CAGE), and daily milk yield (DMY) on the dependent variable of lactation milk yield (LMY) in Anatolian buffaloes. In this study, a total of 3761 LMY records of the 834 Anatolian buffaloes calving between 2012 and 2017 in Tokat province and around were used as the research material. In the study, the simple correlation coefficients between the dependent variable of LMY and independent variables were determined positive and significant (P&lt;0.001). The research specified the direct determination coefficients of the independent variables of the LL, CAGE, and DMY on the dependent variable of LMY as 0.378, 0.004, and 0.350, respectively. The path coefficients related to LL, CAGE, and DMY were determined as 0.615, 0.021, and 0.592, respectively. Since the DMY and LL examined in the study had a high direct impact on the lactation milk yield, therefore it could be suggested that using these data as criteria in breeding programs conducted in the herds evaluated in the study will increase the success in the selections applied.

Human Milk-Derived Levels of let-7g-5p May Serve as a Diagnostic and Prognostic Marker of Low Milk Supply in Breastfeeding Women.

Low milk supply (LMS) is associated with early breastfeeding cessation; however, the biological underpinnings in the mammary gland are not understood. MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally downregulate gene expression, and we hypothesized the profile of miRNAs secreted into milk reflects lactation performance. Longitudinal changes in milk miRNAs were measured using RNAseq in women with LMS (n = 47) and adequate milk supply (AMS; n = 123). Relationships between milk miRNAs, milk supply, breastfeeding outcomes, and infant weight gain were assessed, and interactions between milk miRNAs, maternal diet, smoking status, and BMI were determined. Women with LMS had lower milk volume (p = 0.003), were more likely to have ceased breast feeding by 24 wks (p = 0.0003) and had infants with a lower mean weight-for-length z-score (p = 0.013). Milk production was significantly associated with milk levels of miR-16-5p (R = -0.14, adj p = 0.044), miR-22-3p (R = 0.13, adj p = 0.044), and let-7g-5p (R = 0.12, adj p = 0.046). Early milk levels of let-7g-5p were significantly higher in mothers with LMS (adj p = 0.0025), displayed an interaction between lactation stage and milk supply (p < 0.001), and were negatively related to fruit intake (p = 0.015). Putative targets of let-7g-5p include genes important to hormone signaling, RNA regulation, ion transport, and the extracellular matrix, and down-regulation of two targets (PRLR and IGF2BP1/IMP1) was confirmed in mammary cells overexpressing let-7g-5p in vitro. Our data provide evidence that milk-derived miRNAs reflect lactation performance in women and warrant further investigation to assess their utility for predicting LMS risk and early breastfeeding cessation.

A Comparative Study of Productive and Reproductive Performance between Mpwapwa Breed Cattle and Their Crosses

Mpwapwa cattle, a Tanzanian composite dual-purpose breed which was established in 1960s is suitable for medium to low input production systems, but is faced with limited country-wide distribution. The aim of this study was to assess the productive and reproductive performances of Mpwapwa cattle breed and its crosses reared at Tanzania Livestock Research Institute (TALIRI). Retrospective data on age at first calving (AFC), calving interval (CI), pregnancy percentage (PP), lactation length (LL), average milk yield per day (AMYD) and total lactation milk yield (TLMY) obtained from 295 cows with the total of 885 lactations during five consecutive years (2015-2019) were analyzed. Overall mean of AFC, CI, PP, LL, AMYD and TLMY were 38.5±5.9 months, 19.92±5.64 months, 29.1%±14.4%, 237.72±71.20 days, 2.65±1.12 liters and 667.18±397.11 liters, respectively. The results of AFC, CI, LL and TLMY showed significance difference (p &lt; 0.05) between Mpwapwa breed cattle and its crosses except for PP which did not show significance difference (p &gt; 0.05). The results shows that reproductive and productive performance of Mpwapwa breed cattle and its crossbred cows was lower compared to the breeding goal of this breed. Therefore, it is recommended to investigate factors required to improve reproductive and productive performances to meet the intended objectives of establishing Mpwapwa Breed

Dynamics of changes in milk productivity of brown Swiss cows of local breeding in the conditions of Armenia

Relevance. In the Republic of Armenia, the leading branch of animal husbandry is cattle breeding. More than 95 % of the milk and 60% of the meat are obtained from cattle breeding. In order to further develop cattle breeding in the republic within the framework of various state and commercial programs, since 2007, Holstein, Brown Swiss, Simmental and Jersey heifers have been imported from European countries. In this regard, the study of adaptive and productive qualities of not only imported, but also received from them animals of the first generation is relevant. Methods. Experimental studies were carried out on the number of dairy cows in the leading livestock farm of OOO “Agroholding “Armenia”” near the city of Spitaka. The processing of the research results was carried out using the method of variation statistics. The article substantiates the age-related changes in the indicators of milk productivity of the daughters of the Brown Swiss breed of the first generation, obtained from mothers imported from Germany, at I; II and III lactation (2016–2021). The farm has a system of keeping cows year-round stall, with loose-box method of keeping. Cows are fed and milked twice a day. The study determined the milk yield, the fat and protein content in milk (monthly control milking), the live weight of cows (by weighing), the lactation coefficient and milk yield repeatability coefficients. Results. According to the results of the research, Brown Swiss cows obtained from imported mother cows had sufficiently high indicators of milk productivity and live weight, which naturally increased with age. In cows, milk yield from I to III lactation was 6845; 7630 and 8450 kg, respectively, the fat and protein content in milk was 4.08; 4.03; 4.0 % and 3.2; 3.16; 3.12 %, live weight was 550; 595 and 630 kg, and the milk coefficient was 12.4; 12.8 and 13.4.

Study of effect of various genetic and non-genetic factors on milk yield in Frieswal cattle

The present study was carried out on data of 3,425 Frieswal cattle (Holstein Friesian × Sahiwal cattle) maintained at Military Farm, Pimpri, Pune, Maharashtra. Total 9,094 lactation records were collected from 3,425 cows born to 239 sires. The data were analyzed using SAS software. The collected data were normalized and utilized for studying effect of genetic and non-genetic factors on milk yield. The PROC GLM procedures of SAS were used to quantify the effect of non-genetic factors on milk yield. The non-genetic factors considered for the present study were period of calving, season of calving and parity whereas, the covariate considered was age at first calving (AFC). The estimated overall least squares mean of lactation milk yield was observed as 3188.65±10.93 kg in Frieswal cattle. The effect of period of calving, and parity was highly significant on lactation milk yield while the season of calving had significantly affected the milk yield. The age of first calving as a covariate had highly significant effect on milk yield. Amongst the genetic factors, the effect of sire was considered and found to be highly significant on lactation milk yield.

Evaluation of production performance of Binjharpuri cattle of Odisha

Binjharpuri, a dual purpose indigenous breed of Odisha is commonly reared for its various advantages, viz. optimum milk production in low input management system, excellent draft ability in hot humid climate condition and heat resistance ability. In the present study, attempt was made to evaluate production performance along with influence of non- genetic effects such as location, lactation order and season of calving on production traits of binjharpuri cattle. The overall average least square means along with standard error for lactation milk yield, average daily milk yield, peak yield, lactation length and dry period were found to be 974.490±6.788 kg, 3.557±0.023 kg, 4.633±0.021 kg, 274.444±1.249 days and 121.913±0.611 days, respectively. Location had highly significant effect on lactation milk yield, average daily milk yield, lactation length and dry period, whereas non-significant effect on peak yield. Lactation order too had highly significant effect on the traits considered under study. Season of calving had highly significant effect on lactation milk yield, average daily milk yield; significant effect on lactation length whereas non-significant effect on peak yield and dry period. Significant influence of non-genetic factors and significant variations in traits under study is suggestive that remarkable improvement in the Binjharpuri cattle populace can be targeted through better management and by nurturing effective breeding strategies.

PHENOTYPIC TRENDS FOR MILK YIELD IN NILI RAVI BUFFALOES REGISTERED UNDER BULL MOTHER SCHEME AND AT LIVESTOCK EXPERIMENT STATION BAHADURNAGAR- OKARA

Efficient breeding plans depend upon the availability of reliable and accurate data.To evaluate the productive and reproductive performance of the Nili-Ravi buffalo, registered under thebull mother scheme, was evaluated from 1980-2020. General Linear Model is used to study the effectof phenotypic characters on milk yield i.e., year of calving, age at first calving, and dam’s parity onproductive traits under consideration. The lactation records of all parity are used for the analysis. Thedata on pedigrees, breeding, and performance records through analysis of variance procedure showsstatistically significant (P &lt; 0.05) differences for the effect of 305 days milk yield and lactation length.The Least Squares Mean for lactation milk yield, age at first calving and lactation length are 2108.62 ±12.80 liters, 1574.49 ± 8.1 and 295.50 ± 1.47 days, respectively. The inclusive results depict thatbuffaloes calve in the winter season have the highest and most significant total milk yield. The data setcould be used as a phenotype for genome-wide association studies as a reference population.

Modelling of the first lactation milk yield of Frieswal cows using different mathematical functions

A study was conducted to find the most appropriate mathematical model that describes the first lactation milk yield of Frieswal cattle. Data on 42,368 individual first lactation test day yields of 1,072 Frieswal cows calved during 2005 to 2014 in Ambala and Meerut Military dairy farms were utilized for the study. The first test day milk yield was recorded on 6thday after calving while the subsequent records were collected at seven days interval and so the average 43 test day yields were taken for fitting the lactation curve models. Five different mathematical models, viz. Exponential decline function (EDF), Parabolic exponential function (PEF), Inverse polynomial function (IPF), Gamma function (GF) and Mixed log function (MLF) were fitted.The accuracy of fitting (R2 value) the models revealed that the MLF (96.14) was more appropriate followed by IPF (95.57), GF (93.85), PEF (83.68) and EDF (69.09). The RMSE estimate of MLF was lowest (0.3483) as expected while the EDF had the highest RMSE value of 0.9858.The AIC criterion was lowest for IPF (5.7175) and highest for GF (8.0212). The BIC values of five functions ranged between –83.6262 for MLF to 3.1809 for EDF. All the DW estimates were positive and ranged between 0.3656 for EDF to 0.7106 for GF indicating positive autocorrelation between the residuals. Based on the results obtained in the present study, it may be inferred that the first lactation yield was explained accurately by the mixed log function (MLF) in Frieswal cattle. As the inverse polynomial (IPF) and gamma function (GF) also had satisfactory results, these two functions can also be used for fitting the lactation curve models in Frieswal cattle. On the other hand, exponential decline function and parabolic exponential functions least explain the first lactation curve in Frieswal cattle.

Genotyping of the κ - casein gene by PCR - RFLP (AcuI digestion) and its relationship to milk yield traits in Anatolian buffaloes, Murrah buffaloes, and their crosses

The aim of this study was to investigate the polymorphism of the κ - casein gene (kappa casein, CSN3) in buffaloes and determine its effects on milk yield traits. Data were obtained from 2016 to 2019 from all animals in the ongoing Anatolian Buffalo Breeding Project. Genomic DNA was collected from a total of 209 buffaloes of different ages and sexes, namely 31 Murrah, 46 Anatolian buffaloes, and 132 of their crosses (Murrah × Anatolian). Genotyping of CSN3 gene by polymerase chain reaction-restriction fragment length polymorphism (PCR - RFLP) technique with restriction enzyme (AcuI) revealed three genotypes: AA (0.689), AB (0.282), and BB (0.028), and the frequencies of A and B alleles were 0.83 and 0.17, respectively. A total of 113 milk yield data and 74 milk component analyses of dairy buffaloes were used to compare CSN3 genotypes for milk yield traits. Statistical analysis showed that there was a significant difference in lactation milk yield between CSN3 genotypes: BB, 1560.3 ± 326.7 kg, AB, 1278.1 ± 111.3 kg, and AA, 1060.9 ± 85.6 kg (p < 0.05). However, the mean values of lactation length and milk components were not significant between genotypes (p > 0.05). These results suggest that these variations (135$^{ThrACC / IleATC}$ /136$^{ThrACC / ThrACT}$) in the buffalo CSN3 gene may be used as genetic markers in dairy buffalo breeding programs.

The effect of antibiotic versus no treatment at dry-off on udder health and milk yield in subsequent lactation: A retrospective analysis of Austrian health recording data from dairy herds.

Bovine mastitis is the most commonly diagnosed disease of dairy cows worldwide and causes extensive economic losses to milk producers. Intramammary infection status before dry-off plays a decisive role with respect to udder health and milk yield in the subsequent lactation. The aim of this study was to compare the effect of antibiotic dry cow therapy (DCT) versus no treatment at dry-off on milk yield, somatic cell count (SCC), inflammation of the mammary gland (IMG), and the incidence of clinical mastitis in the subsequent lactation. Dairy herd data from 251 Austrian dairy farms were recorded over an observation period of 12 mo and subsequently analyzed. The data set included 5,018 dairy cows: 2,078 were treated with antibiotics (abDCT group) and 2,940 were not treated (noDCT group) at dry-off. The abDCT group was subdivided, based on the antimicrobial active substances used for drying off, into 4 different groups (penicillins, cloxacillin, cephalosporins, and rifaximin). Based on bacteriological culture results, infections were grouped into those caused by major, minor, and other pathogens. Additionally, the IMG was defined via SCC from milk recording data using a cutoff of 200,000 cells/mL before drying off and after calving. The incidence of clinical mastitis cases within 30 and 90 d in milk was calculated using veterinary diagnosis data. To investigate the effect of different dry cow therapies on the following parameters: milk yield, SCC, and diagnosed clinical mastitis cases, different linear mixed models were constructed. Overall, the abDCT group was determined to have a significantly higher milk yield over 305 d in milk in the subsequent lactation (increase of 6.18%), compared with the noDCT group (increase of 4.29%). Both groups (abDCT and noDCT) demonstrated a decrease in the first SCC after calving compared with the SCC before dry-off, although the treated cows had a significantly higher reduction. Regarding the different antibiotic groups, with exception of the rifaximin treated cows, all antibiotic groups showed a significant difference from not treated cows with respect to SCC. Additionally, we were able to demonstrate that cows with IMG before dry-off had a 2.073 times higher chance of an increased SCC (>200,000 cells/mL) after calving. With respect to the veterinary diagnosis data, neither the IMG before drying off nor the type of DCT had a significant influence on the probability of developing clinical mastitis within 30 or 90 d in milk. Only a small number of treatments was accompanied with a bacteriological examination before drying off. However, the existing data in this study indicates that the intramammary infection status before dry-off in combination with different dry cow treatments influences udder health and milk yield after calving. Nevertheless, further studies with larger data sets of bacteriological examinations are necessary to enable a more in-depth investigation into the effects of different antibiotic substances used for DCT.