Early Stages Of Lactation Research Articles

Quantification and prediction of enteric methane emissions from Chinese lactating Holstein dairy cows fed diets with different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios

Methane (CH4) emissions from ruminant production are a significant source of anthropogenic greenhouse gas production, but few studies have examined the enteric CH4 emissions of lactating dairy cows under different feeding regimes in China. This study aimed to investigate the influence of different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios on production performance, nutrient digestibility, and CH4 emissions for Holstein dairy cows at various stages of lactation. It evaluated the performance of CH4 prediction equations developed using local dietary and milk production variables compared to previously published prediction equations developed in other production regimes. For this purpose, 36 lactating cows were assigned to one of three treatments with differing dietary NDF/NFC ratios: low (NDF/NFC = 1.19), medium (NDF/NFC=1.54), and high (NDF/NFC=1.68). A modified acid-insoluble ash method was used to determine nutrient digestibility, while the sulfur hexafluoride technique was used to measure enteric CH4 emissions. The results showed that the dry matter (DM) intake of cows at the early, middle, and late stages of lactation decreased significantly (P<0.01) from 20.9 to 15.4 kg d−1, 15.3 to 11.6 kg d−1, and 16.4 to 15.0 kg d−1, respectively, as dietary NDF/NFC ratios increased. Across all three treatments, DM and gross energy (GE) digestibility values were the highest (P<0.05) for cows at the middle and late lactation stages. Daily CH4 emissions increased linearly (P<0.05), from 325.2 to 391.9 kg d−1, 261.0 to 399.8 kg d−1, and 241.8 to 390.6 kg d−1, respectively, as dietary NDF/NFC ratios increased during the early, middle, and late stages of lactation. CH4 emissions expressed per unit of metabolic body weight, DM intake, NDF intake, or fat-corrected milk yield increased with increasing dietary NDF/NFC ratios. In addition, CH4 emissions expressed per unit of GE intake increased significantly (P<0.05), from 4.87 to 8.12%, 5.16 to 9.25%, and 5.06 to 8.17% respectively, as dietary NDF/NFC ratios increased during the early, middle, and late lactation stages. The modelling results showed that the equation using DM intake as the single variable yielded a greater R2 than equations using other dietary or milk production variables. When data obtained from each lactation stage were combined, DM intake remained a better predictor of CH4 emissions (R2=0.786, P=0.026) than any other variables tested. Compared to the prediction equations developed herein, previously published equations had a greater root mean square prediction error, reflecting their inability to predict CH4 emissions for Chinese Holstein dairy cows accurately. The quantification of CH4 production by lactating dairy cows under Chinese production systems and the development of associated prediction equations will help establish regional or national CH4 inventories and improve mitigation approaches to dairy production.

Genetic analyses of blood β-hydroxybutyrate predicted from milk infrared spectra and its association with longevity and female reproductive traits in Holstein cattle

Ketosis is one of the most prevalent and complex metabolic disorders in high-producing dairy cows and usually detected through analyses of β-hydroxybutyrate (BHB) concentration in blood. Our main objectives were to evaluate genetic parameters for blood BHB predicted based on Fourier-transform mid-infrared spectra from 5 to 305 d in milk, and estimate the genetic relationships of blood BHB with 7 reproduction traits and 6 longevity traits in Holstein cattle. Predicted blood BHB records of 11,609 Holstein cows (after quality control) were collected from 2016 to 2019 and used to derive 4 traits based on parity number, including predicted blood BHB in all parities (BHBp), parity 1 (BHB1), parity 2 (BHB2), and parity 3+ (BHB3). Single- and multitrait repeatability models were used for estimating genetic parameters for the 4 BHB traits. Random regression test-day models implemented via Bayesian inference were used to evaluate the daily genetic feature of BHB variability. In addition, genetic correlations were calculated for the 4 BHB traits with reproduction and longevity traits. The heritability estimates of BHBp, BHB1, BHB2, and BHB3 ranged from 0.100 ± 0.026 (± standard error) to 0.131 ± 0.023. The BHB in parities 1 to 3+ were highly genetically correlated and ranged from 0.788 (BHB1 and BHB2) to 0.911 (BHB1 and BHB3). The daily heritability of BHBp ranged from 0.069 to 0.195, higher for the early and lower for the later lactation periods. A similar trend was observed for BHB1, BHB2, and BHB3. There are low direct genetic correlations between BHBp and selected reproductive performance and longevity traits, which ranged from -0.168 ± 0.019 (BHBp and production life) to 0.157 ± 0.019 (BHBp and age at first calving) for the early lactation stage (5 to 65 d). These direct genetic correlations indicate that cows with higher BHBp (greater likelihood of having ketosis) in blood usually have shorter production life (-0.168 ± 0.019). Cows with higher fertility and postpartum recovery, such as younger age at first calving (0.157 ± 0.019) and shorter interval from calving to first insemination in heifer (0.111 ± 0.006), usually have lower BHB concentration in the blood. Furthermore, the direct genetic correlations change across parity and lactation stage. In general, our results suggest that selection for lower predicted BHB in early lactation could be an efficient strategy for reducing the incidence of ketosis as well as indirectly improving reproductive and longevity performance in Holstein cattle.

Histomorphological Changes in the Mammary Gland of Local Indian Goat during Lactation Cycle

Background: In developing countries goat rearing is the sustainable source of income for marginal farmers. The goat milk contains lower fat per cent (3.5%) as compared to cow (4.1%) and buffalo milk (7.4%), with smaller and homogenous fat globules. It is suitable for the persons with poor digestibility of cow milk and infants having mother milk intolerance. To improve the milk production it is important to understand the mammary gland pattern during the different phases of lactation. The present study aimed at analyzing these changes by histological and histochemical observations. The mammary gland is composed of parenchyma containing acini and stroma including the ductual system. These components change during the lactation cycle. Methods: The present study was conducted on 24 goats, eighteen in lactating stage where as six from nonlactating stage. The mammary glands were collected from local abattoir with known history of stage of lactation and divided into three groups as early lactation (2-4 weeks), mid lactation (5-6 weeks) and late lactation ( greater than 6 weeks). The histological and histochemical studies were performed during the different stages of lactation and in non lactating stage to observe the morphological and morphometrical changes along with the presence and absence of different components. Result: The lobules of the mammary gland were polygonal, triangular, oval or elongated in shape during early lactation stage. Approximately all the alveoli observed in early lactation were filled with variable quantity of eosinophilic substance and appeared foamy, due to presence of variable size of fat vacuoles. In mid lactation the lobules became highly irregular. The long and short diameter of lobules was 1041.69 µm and 563.93 µm, respectively. The intralobular stroma was inconspicuous hence alveolar wall appeared to touch each other. In late lactation lobules became shorter in size. The large alveoli showed folded and collapsed appearance. In nonlactating stage well defined alveoli, clusters of desquamated cells were seen and degenerated alveoli were also observed. These histomorphological changes in the secretory unit of the mammary gland reflect the lactation yield and milk composition during different stages of lactation.

Epidemiology with antibiogram profile of Staphylococcus aureus and Escherichia coli isolated from mastitic milk of dairy cows in Tangail District, Bangladesh

Objective: The purpose of this study is to find out the epidemiological phenomenon of mastitis in dairy cattle and identify the most common pathogens, Escherichia coli and Staphylococcus aureus, in clinical and subclinical mastitis in dairy cattle with their antibiotic profiles of several selected areas of Tangail District, Bangladesh. Materials and Methods: A total of 250 lactating cows were examined in the study area, 28 of which had clinical mastitis, determined by the physical characteristics of milk and udder. Meanwhile, 205 suspected lactating cows were tested for subclinical mastitis using the California Mastitis Test, and 54 were positive. Staphylococcus aureus and E. coli were isolated and identified by conventional techniques such as bacterial culture, Gram stain, and biochemical test. Antimicrobial susceptibility testing was performed by the disk diffusion method. Results: This study reported clinical and subclinical mastitis prevalence as 11.20% (28/250) and 26.34% (54/205), respectively. Out of 72 milk samples, 26 (36.11%) were positive for S. aureus, 15 (20.83%) for E. coli, 22 (30.56%) for mixed organisms, and 9 (12.5%) were unidentified organisms. This study also showed that Friesian cross-breeds cows, the cows with parity 1 to 3, early stage of lactation, and high-yielding dairy cows were significantly more susceptible to mastitis. Antibiogram studies revealed that 85.42% of S. aureus and 64.86% of E. coli were multiple drug resistant (MDR). The S. aureus was found to be highly sensitive to gentamicin (CN) (95.83%) and ciprofloxacin (CIP) (54.17%) and resistant to ceftriaxone (CRO) (75.0%) and oxacillin (68.75%). On the other hand, the E. coli was highly sensitive to CN (97.30%) and CIP (75.68%) and resistant to streptomycin, CRO, and oxacillin at 56.76%. Conclusion: The results of this study may help governments and livestock agencies to ensure that registered veterinarians only prescribe dairy cows and to make farmers aware of mastitis. This will help reduce MDR and prevent threats to human health from consuming milk. Therefore, the rational use of CN and CIP is recommended to effectively resolve most disease cases in dairy cattle.

Prevalence and Associated Risk Factors of Bovine Mastitis on Dairy Cattle in Mogadishu Somalia

Mastitis is one of the main problems that lead to economic inefficiency in dairy farms. In Somalia, the shortage of milk and milk products has many causes, however examination of sub-clinical mastitis and their prevalence has not been adequately addressed and no comprehensive research has been led on their epidemiology. Therefore this study was launched to assess the prevalence of mastitis in Mogadishu as well as identify the risk factors that are associated with mastitis occurrence. The study was cross sectional and took place between March 2019 to February 2020, to determine the prevalence and associated risk factors of mastitis on dairy cattle at Mogadishu, Somalia. The study conducted multistage sampling by first purposely selecting three districts from the 17 districts that comprises Mogadishu province. The area selection was based on the availability of dairy farms. Farms were also randomly selected by first listing farms in a piece of paper and selecting it from the bowel, while systematic selection was conducted at animal level by selecting every four animals for sampling and screening. In this study the overall prevalence found was 44.5% and quarter wise the prevalence was 19%. The present study revealed that the presence of mastitis among different age groups of the examined cattle had statistically significant difference in their prevalence (p<0.05), with the highest prevalence found in cattle 7 years and above of age with prevalence of (51.4%) compared to cattle <7 years of age (25.49 %). The study also revealed a statistically significant association between mastitis and stage of lactation of the cattle with animals with early stage of lactation having the highest prevalence (58.86%) compared to the cattle late stage of lactation with the (12.61%). Study also presented a significant association between prevalence of mastitis and production system was (p<0.005) which is higher in intensive systems with the (47.45%) and lower semi-intensive systems (31.4%). Presence of mastitis and hygienic level was also compared and a significant association was found (p<0.05). According to the breed, a significant difference was not found between the prevalence of exotic and local cattle (p>0.05) although exotic were found to have a slightly higher prevalence (47.33%) compared to local cattle (43.1%). Therefore this study recommended that the regular screening for early detection should be done at least once a week for monitoring udder health status of dairy animals.

​Effect of Dietary Inclusion of Cumin Seed (Cuminum cyminum) on Voluntary Feed Intake, Milk Yield, Milk Quality and Udder Health of Dairy Cows

Background: Plants containing essential oils can be a cost-effective means of improving efficiency of milk production and optimizing milk composition of dairy cows. Cuminum cyminum (green cumin) belongs to the Apiaceae family and is a well-known herbal medicine in Iran. The medicinal properties of cumin may have beneficial effects on milk production. However, very few studies have been reported whereby cumin has been fed to ruminants. Therefore, the present study is design to investigate the effect of cumin supplementation on milk yield, milk quality and udder health of lactating dairy cows. Methods: Twelve multiparous lactating cows at early stage of lactation was selected and randomly allotted to two equal groups (n=6) on the basis of milk yield. In addition to normal routine feeds and fodders, cows in groups T1 was fed cumin seed @ 50 g/d/head for 90 days. Fortnightly body weight was determined on the basis of body measurement of animals. All feed samples was analysed for proximate composition, Ca and P. The daily milk yield (kg/d) of individual cows was recorded by weighing. Milk samples were collected after complete milking and thorough mixing for determination of milk composition. Udder health was monitored by MCMT (modified california mastitis test), measuring milk pH and SCC (somatic cell count) at fortnightly intervals. Result: The results indicated that overall mean body weight, average DMI was statistically (P greater than 0.05) similar in both the groups. The average milk yield (kg) of animals was statically non significant (P greater than 0.05) but numerically 20.64% higher milk yield was observed in cumin seed supplemented group than control group. There was no effect of cumin supplementation on chemical composition (Fat, TS, SNF, Lactose and Protein) of milk in dairy cows. Overall mean milk pH and somatic cell count (SCC) in both the groups was statically similar but numerically lower in treatment group. The overall mean (%) of MCMT positive animals was 14.29 and 9.52 in T0 (Control) and T1 (Treatment) groups, respectively. From the results it can be deduced that the cumin seed (Cuminum cyminum) supplementation improves milk yield by 20.64%. However, it has no effect on composition of milk in dairy cows. Supplementation improved the udder health and found no effect on dry matter intake (DMI) in dairy cows.

Alterations in the Hemato-biochemical, Endocrine, Somatic Cell Count and Milk Composition in Lactating Tarai Buffaloes during Different Lactation Stages

Background: Tarai buffalo is indigenous buffalo breed of Uttarakhand state, dual purpose, well adapt to hot-humid climatic condition of Tarai area. This study aimed to evaluate the alterations in the hemato-biochemical, endocrine, milk somatic cell count and milk composition in lactating Tarai buffaloes. Methods: Thirty-six healthy Tarai buffaloes were selected from four different Gujjar farms and divided into four groups consisting nine buffaloes in each group as early (60±30 days), mid (120±30 days) and late (180±30 days) lactation stages and dry buffaloes. Both blood and milk samples were collected once from each lactation stage of selected animals. Hematological parameters and milk composition were evaluated by standard procedures and methods. Biochemical and endocrine parameters were evaluated using commercially available kits as per manufacturer’s protocol. Milk somatic cell count (SCC) was done by direct microscopic counts using Newman Lampert stain. Result: It observed significantly (p less than 0.05) higher TLC value but lower plasma glucose, cholesterol, calcium, phosphorus and urea levels during early lactation stage. Significantly (p less than 0.05) declined in plasma total protein during late lactation stage and triglyceride in dry cows. Plasma hormone significantly (p less than 0.05) higher in cortisol during early lactation while higher T4 and insulin in late lactation stages. Milk fat, urea and total solids were significantly (p less than 0.05) decreased during early lactation and again increased during late lactation while milk SCC significantly (p less than 0.05) higher during early and late lactation stages.

Random Regression Model for Genetic Evaluation and Early Selection in the Iranian Holstein Population.

Simple SummaryThe objective of this study was to use a model to predict breeding values for sires and cows at an early stage of the first lactation of cows and progeny groups in the Iranian Holstein population to support the early selection of sires. Our results show that we can select sires according to their daughters’ early lactation performance before they finish first lactation. Cross-validation results show that early selection accuracy can be high, and such an early selection can decrease the generation interval and lead to an increased genetic gain in the Iranian Holstein population.The objective of this study was to use a model to predict breeding values for sires and cows at an early stage of the first lactation of cows and progeny groups in the Iranian Holstein population to enable the early selection of sires. An additional objective was to estimate genetic and phenotypic parameters associated with this model. The accuracy of predicted breeding values was investigated using cross-validation based on sequential genetic evaluations emulating yearly evaluation runs. The data consisted of 2,166,925 test-day records from 456,712 cows calving between 1990 and 2015. (Co)-variance components and breeding values were estimated using a random regression test-day model and the average information (AI) restricted maximum likelihood method (REML). Legendre polynomial functions of order three were chosen to fit the additive genetic and permanent environmental effects, and a homogeneous residual variance was assumed throughout lactation. The lowest heritability of daily milk yield was estimated to be just under 0.14 in early lactation, and the highest heritability of daily milk yield was estimated to be 0.18 in mid-lactation. Cross-validation showed a highly positive correlation of predicted breeding values between consecutive yearly evaluations for both cows and sires. Correlation between predicted breeding values based only on records of early lactation (5–90 days) and records including late lactation (181–305 days) were 0.77–0.87 for cows and 0.81–0.94 for sires. These results show that we can select sires according to their daughters’ early lactation information before they finish the first lactation. This can be used to decrease generation interval and to increase genetic gain in the Iranian Holstein population.

Seasonal variations in the characteristics of milk fat and the whipping properties of cream

This study investigated the seasonal variations in the fatty acid composition and the melting behaviour of milk fat and the whipping properties of cream in New Zealand. Major changes in the fatty acid composition from early to mid-season were consistent with those reported during the early stage of lactation, whereas some of these changes reverted from mid-to late season. The milk fat globule size was largest in the early season while the solid fraction of milk fat was largest in the mid-season (P < 0.001), both of which were associated with the fatty acid composition. The whipping properties of cream were most desirable during the early season, with the shortest whipping time and the highest firmness of the whipped cream (P < 0.05). The fat globule size and protein content of the cream may have played the most important roles in affecting its whipping properties over the seasons.

Substitution Value of Cup Plant (Silphium perfoliatum L.) Silage in Dairy Cow Diet

Cup plant (Silphium perfoliatum L.) may serve as an alternative perennial forage crop in lowlands of the north central United States. Three feeding trials were conducted with Holstein cows (Bos taurus) at the early, mid, and late lactation stages to evaluate the impact of different cup plant silage substitution levels for alfalfa (Medicago sativa L.)-corn (Zea mays L.) silage mixture on milking cow performance. The concentrations of lignin and CP (crude protein) in the first cut and regrowth cup plant silage were lower than alfalfa silage. Substituting one-half of the silage reduced voluntary dry matter (DM) intake of early lactation stage cows by 11%. Although milk composition was not changed by the substitution, the 4% FCM (fat corrected milk) production was reduced by 7.5%. Another feeding trial tested substitution of one-third and two-thirds of the silage for mid-lactation cows. Increasing cup plant silage up to two-thirds of the forage portion in the diet reduced DM intakes and 4% FCM production by 21.8 and 8.7%, respectively. Milk composition did not change. Cow bodyweight was reduced as the substitution rate increased. Finally, a feeding trial with late-lactation cows indicated substitution of one-fourth of the silage performed equivalent in DM intake, milk composition, and milk production to those of cows fed a low forage diet (50% alfalfa-corn silage in diet), or a high forage diet (66% alfalfa-corn silage in diet). Based on the results of the three feeding trials, it is concluded that cup plant silage can substitute mixture of alfalfa-corn silage at up to 30% of the forage portion in diets without substantial negative impacts on the performance of dairy cows, especially during late lactation.

Postpartum cows showed high oocyte triacylglycerols concurrently with high plasma free fatty acids

Impaired oocyte quality is one of the main causes of low fertility in modern high-yielding dairy cows. One of the potential factors of the impaired oocyte quality is the effects of free fatty acids (FFA). In fact, high FFA supplementation to culture media exacerbated oocyte developmental competence in vitro. Meanwhile, artificially induced high blood FFA levels in heifers did not affect the lipid composition of oocytes in vivo; however, the oocyte lipid profile of postpartum cows has not yet been investigated. Therefore, the profile of lipids involved in energy metabolism, including FFA and triacylglycerols (TAG), and their relationship between plasma and oocytes were compared among cows at different lactation stages. Heifers were used as a control group that was not affected by lactation. Plasma and oocytes were collected from heifers (n = 4) and 14 Holstein cows categorized to the early lactation stage: 25–47 days in milk (DIM) (n = 6), peak lactation stage: 61–65 DIM (n = 4), and middle lactation stage: 160–202 DIM (n = 4). The FFA and TAG profiles of plasma and oocytes were examined by liquid chromatography mass spectrometry. Plasma FFA positively correlated with oocyte TAG (P < 0.05). Plasma FFA and oocyte TAG were significantly higher in cows in the early lactation stage than in heifers (P < 0.05), while the peak and middle lactation stage groups had intermediate levels. The proportion of oleic acid in plasma increased concurrently with elevations in total FFA, while the compositions of oocyte FFA and TAG fatty acyls were constant regardless of plasma FFA concentration or oocyte TAG content. The present results suggest that high postpartum plasma FFA concentrations affect the quantity of oocyte TAG. Taken together with the adverse effects of high FFA concentrations on oocyte developmental competence in vitro, oocyte quality in postpartum cows may be impaired due to high circulating FFA concentrations. These results provide a more detailed understanding of the effects of postpartum high circulating FFA concentrations on the low fertility of cows.

Prevalence and Risk Factors of Clinical Mastitis in Holstein Cows under Subtropical Egyptian Conditions

The current study was built on 1015 dairy records of Holstein Friesian cows, aimed to determine the prevalence and risk factors of clinical mastitis (CM). Logistic regression models were conducted to determine the risk factors associated with the onset of CM. The average age at 1st calving was 1.98 years in mastitic cows, and 2.01 years in healthy onest. DMY was shown to be somewhat lower in mastitic cows than in healthy (31.9 and 32.3 kg, respectively). Older dairy cows >5 years had a higher incidence of mastitis (53.56%). The prevalence of CM was higher in multiparous cows, either 2nd parity (48.24%) or ≥ 3rd parity (47.23%). Regarding the calving season, cows that calved in winter showed a lower percentage of CM (38.36%). Pregnant cows were found to have a greater incidence of CM than non-pregnant cows (59.35% and 32.89%, respectively). Concerning the history of the previous mastitis, cows that were infected previously showed a higher prevalence of CM (51.66%). The greatest percentage of CM was observed in cows in the early and mid stages of lactation (44.59% and 52.69%, respectively). The final multivariate logistic regression model revealed that age at 1st calving had a significant positive correlation with the incidence of CM (β=1.19, P-value= 0.003). Older cows >5 years ( (OR=1.79), cows calved during the summer season (OR=1.84), Pregnant cows (OR=7.27), cows with a history of previous mastitis (OR=1.81), and lactating cows at early lactation stage (1-90 days) were significant risk factors associated with an increased incidence of CM.

Evaluation of Milk Production and Milk Composition at Different Stages of Saanen Dairy Goats

Milk is an important elements due to its high nutritious and balanced in human diet. In Asian, goat milk is the most consumed because of the unique taste, more nutritious than cow milk. However, milk production and composition values differ at every stage of lactation in goats. Thus, determining the highest milk production and producing the best quality goat milk is essential to satisfy the local market demands. The objective of the present study is to determine the milk yield and milk composition at different lactation stages and to evaluate the lactation curves in Saanen goats. The lactation stages can be categorized into three, early (less than 80 days), mid (80 – 140 days) and late (over 140 days) days in milk (DIM). In total, 90 milk samples were collected from 15 goats representing early (n=5), mid (n=5), and late (n=5) stages of lactation. The Saanen goats were raised under the same conditions, and milking was done early in the morning (9.00am).The milk yield from Saanen goats were collected and measured weekly at each stage of lactation. Milk samples were analyzed for fat, protein, solid non-fat, and lactose. Current result illustrated, there were significant different (p ˂ 0.05) among three stages of lactation in milk yield, solid non-fat, fat, protein and lactose. In terms of food regulation, the Saanen goats almost fully met the standard requirements for milk production and composition. In addition, this study also observes the lactation curves in Saanen goats and analyse the curve shapes and patterns. The average milk yields from three different stages develops a concave downward curve. The results indicated that mid yield increased from early to mid- lactation and decreased thereafter until the end of lactation.

A data-driven prediction of lifetime resilience of dairy cows using commercial sensor data collected during first lactation

Reliable prediction of lifetime resilience early in life can contribute to improved management decisions of dairy farmers. Several studies have shown that time series sensor data can be used to predict lifetime resilience rankings. However, such predictions generally require the translation of sensor data into biologically meaningful sensor features, which involve proper feature definitions and a lot of preprocessing. The objective of this study was to investigate the hypothesis that data-driven random forest algorithms can equal or improve the prediction of lifetime resilience scores compared with ordinal logistic regression, and that these algorithms require considerably less effort for data preprocessing. We studied this by developing prediction models that forecast lifetime resilience of a cow early in her productive life using sensor data from the first lactation. We used an existing data set from a Dutch experimental herd, with data of culled cows for which birth dates, insemination dates, calving dates, culling dates, and health treatments were available to calculate lifetime resilience scores. Moreover, 4 types of first-lactation sensor data, converted to daily aggregated values, were available: milk yield, body weight, activity, and rumination. For each sensor, 14 sensor features were calculated, of which part were based on absolute daily values and part on relative to herd average values. First, we predicted lifetime resilience rank with stepwise logistic regression using sensor features as predictors and a P-value of <0.2 as the cut-off. Next, we applied a random forest with the 6 features that remained in the final logistic regression model. We then applied a random forest with all sensor features, and finally applied a random forest with daily aggregated values as features. All models were validated with stratified 10-fold cross-validation with 90% of the records in the training set and 10% in the validation set. Model performances expressed in percentage of correctly classified cows (accuracy) and percentage of cows being critically misclassified (i.e., high as low and vice versa) ± standard deviation were 45.1 ± 8.1% and 10.8% with the ordinal logistic regression model, 45.7 ± 8.4% and 16.0% with the random forest using the same 6 features as the logistic regression model, 48.4 ± 6.7% and 10.0% for the random forest with all sensor features, and 50.5 ± 6.3% and 8.4% for the random forest with daily sensor values. This random forest also revealed that data collected in early and late stages of first lactation seem to be of particular importance in the prediction compared with that in mid lactation. Accuracies of the models were not significantly different, but the percentage of critically misclassified cows was significantly higher for the second model than for the other models. We concluded that a data-driven random forest algorithm with daily aggregated sensor data as input can be used for the prediction of lifetime resilience classification with an overall accuracy of ~50%, and provides at least as good prediction as models with sensor features as input.

Detection of Subclinical Ketosis in Urine of Cattle and Buffaloes

Background: Subclinical ketosis (SCK) in dairy cows is a common metabolic disorder and a strong determinant of the health and performance of cows throughout lactation. Considerable amount of milk loss takes place with SCK incidence in dairy animals. Greater benefits are to be gained by monitoring the cows for SCK. The current study was aimed to find out incidence of SCK by urine test strip (Keto-Diastix). Methods: The present investigation was carried out on crossbred and Sahiwal cows and Murrah buffaloes (n=180) of the institute herd and rural dairy farms (n=97) around Karnal. The urine samples were tested for subclinical ketosis (SCK) 5-60 days postpartum from August 2019 to March 2020. Meteriological data on wet and dry bulb temperature and ambient temperature was collected and THI was calculated. Data of SCK incidence was classified based on stages of early lactation (5-20, 21-40 and 41-60d), parity (I, II, III and above), seasons (hot-humid, autumn, winter and spring) and milk production level ( less than 10kg, 10-20 kg and greater than 20 kg/d). Milk yield and environment variables were recorded during the experiment. Urine ketone and glucose level was detected by keto-Diastix to find out incidence of SCK. Result: Mean level of ketone bodies in urine was higher (P less than 0.01) in high yielding cows as compared to the medium yielders; however it did not vary in buffaloes. Ketone bodies in urine were high (P less than 0.01) in crossbred cows than that of buffaloes and Sahiwal cows. Urine glucose level did not vary among cows and buffaloes. It is concluded that high producing crossbred cows are more vulnerable to SCK between 41-60d of lactation and in III parity and above due to peak milk production. Sahiwal cows and buffaloes suffer less from SCK probably due to medium level of milk production. Factors like high milk yield, higher parity and hot-humid stress makes the animal more vulnerable to SCK. The screening of urine samples of animals at monthly intervals may be practiced by the farmers to monitor the incidence of SCK.

Associations of udder biometry with subclinical mastitis in Gir crossbred cows

The investigation was undertaken on 110 Gir crossbred cows of different order of lactation and stage of lactation maintained at Research Cum Development Project on Cattle, MPKV, Rahuri. The overall least squares means of udder length, udder width, udder depth and udder circumference were 65.23 ± 1.45, 63.24 ± 1.45, 19.03 ± 0.51 and 86.49 ± 1.50 cm respectively. The least squares analysis of variance showed significant (P&lt;0.05) effect due to order of lactation on udder length in crossbred cows. Also, order of lactation had significant (P&lt;0.01) effect on udder width and udder circumference. However, stage of lactation exerted non-significant influence on all udder measurement traits. In crossbred cows udder length had positive and significant (P&lt;0.01) correlation with udder width, udder circumference and udder depth. The correlation of udder width with udder circumference and udder depth was positive and highly significant (P&lt;0.01). There was positive and significant (P&lt;0.01) correlation of udder circumference with udder depth. The frequencies of trough, round, goaty and pendulous type udder in crossbred cows were 63.64%, 8.18%, 11.82% and 16.36% respectively. Among 110 cows 48 (43.64%) cows were found positive for subclinical mastitis. The higher occurrence of subclinical mastitis was observed in cows having pendulous udder (66.66%) followed by goaty (53.84 %), round (44.44 %) and trough (35.71 %) shape udder. Maximum number of positive subclinical mastitis cases were found in larger udder length (&gt;75 cm), udder width (&gt;75 cm), udder depth (&gt;25 cm) and udder circumference (&gt;95 cm). Highest occurrence (78.26%) of subclinical mastitis was found in cows of sixth and above lactation. Maximum occurrence of subclinical mastitis was noted in cows which were in late (46.15%) stage of lactation followed by early (40%) and mid (37%) stage of lactation. The traits udder shape, udder length and udder depth had positive and significant association with incidence of subclinical mastitis in crossbred cows.

Effect of bypass fatty acid and Tinospora cordifolia supplementation on production performance and milk fatty acid profiling in Murrah buffaloes (Bubalus bubalis).

Buffaloes contribute about 49% of total milk production and are considered as major milk-producing animals in India. During the early stage of lactation, mostly high producing animals suffer from negative energy balance (NEB) due to imbalance between the needs and availability of energy, and this NEB has a negative impact on production and health of buffaloes. Taking this into consideration, a study was conducted at National Dairy Research Institute, Karnal on 20 freshly calved healthy Murrah buffaloes (Bubalus bubalis). Buffaloes were grouped depending on their previous milk yield, body weight, and parity as T0 (control), T1 (fatty acids), T2 (Tinospora), and T3 (mix) groups having five animals each. Supplementation of 150g of bypass fatty acids in T1 group, 150g of Tinospora powder in T2 group, and combination of 150 of bypass fatty acid and 150g of Tinospora powder in T3 group over and above the standard feeding schedule was done for a duration of 90days whereas standard feeding schedule was followed in T0 group. A significant (P < 0.05) increase in average daily milk yield was observed in T1 (10.06 ± 0.56kg/d/h), T2 (10.30 ± 0.53kg/d/h), and T3 (10.11 ± 0.48kg/d/h) in comparison to control group (8.05 ± 0.38kg/d/h). Significantly (P < 0.05) higher milk fat percent and total solids were also recorded in treatment groups over the control group. Other milk constituents (SNF, protein, lactose, ash) and milk properties (pH, conductivity, freezing point, density) remained unaffected by the supplementations. The somatic cell count values were significantly (P < 0.05) decreased in T2 and T3 with the advancement in the lactation in comparison to T0 and T1. Supplementation also leads to significantly (P < 0.05) higher MUFA and PUFA contents in milk of treatment group buffaloes in comparison to control group. The study outcomes state that combination of bypass fatty acids and Tinospora cordifolia supplementation improves milk production and its composition in lactating Murrah buffaloes.

Expression profile of different classes of proteases in milk derived somatic cells across different lactation stages of indigenous cows (Bos indicus) and riverine buffaloes (Bubalus bubalis)

Proteases play a significant role in milk and its products by affecting flavor, texture and longevity. The expression of endogenous proteases varies across different stages of lactation. The study was conducted to understand the transcriptional pattern of different classes of protease-pathways associated genes (CTSB, CTSD, CTSH, CTSL, CTSK, CTSS, CTSZ, PLAU, PLAT) and potential protease inhibitors (SERPIN E2 and SERPIN F2) in 40 milk somatic cells (MSC) samples isolated during early, peak, mid and late lactation stages of Sahiwal cows and Murrah buffaloes – the two most important dairy breeds of India. In Sahiwal cows, except CTSK and PLAU, the expression of other proteases class was not affected significantly (p > 0.05) across lactation stages. However, in Murrah buffaloes, the expression of different proteases increased as the lactation progressed. Most of the proteases showed lower expression during early and peak lactation stages while their expression tends to increase during mid to late lactation stages. The overall trend was somewhat similar in both the dairy species albeit the level of expression was higher in buffalo MSC as compared to cow MSC. The study has provided valuable information on expression kinetics of different proteases in milk somatic cells of two major dairy breeds of India.

Effect of Different Watering Regimes in Summer Season on Water Intake, Feed Intake, and Milk Production of Marecha She-camel (Camelus dromedarius).

Simple SummaryCamel livestock is a significant sector of agriculture in Pakistan. Punjab Marecha is the camel breed more diffuse for their production characteristics. In fact, this camel breed is well adapted to the desert ecosystem, tolerating elevated temperatures and dehydration. This study aimed to evaluate the effect of water deprivation on milk production performance in Marecha camels during the summer. Twelve she-camels in the early lactation stage were included. After seven days, camels were divided into three groups: Group 1 (G1) having access to water once a day, Group 2 (G2) having access once every 4 days, and Group 3 (G3) having access once every 6 days. Milk production and daily dry matter were decreased in camels deprived of water for 6 days. The results of the current study suggest that the camel is a productive animal even when subjected to water deprivation; however, its feed intake and milk production are decreased.Twelve lactating healthy Marecha she-camels in the early lactation stage during the summer at Camel Breeding and Research Station Rakh-Mahni (Pakistan) were included. All animals were fed with Medicago sativa and Cicer arientinum ad libitum and divided into three groups in relation to the access to water, after a period of seven days of adaptation to experimental conditions. Group 1 (G1) was considered as control having access to water once every day; Group 2 (G2) had access once every 4 days, while Group 3 (G3) had access once every 6 days. The duration of the study was 60 days with an adaptation period to experimental conditions of 7 days before the onset of the study. Dry matter intake (DMI) was calculated on a dry matter basis. On average the ambient temperature and relative humidity during the trial were 39–41 °C and 55–63%, respectively. The DMI, water intake, milk production, and body weight changes were affected (p < 0.001) during various watering regimes. The mean values of water intake were found to be 82.94 ± 1.34 L higher in G3 than G1 and G2.

The hidden cost of disease: I. Impact of the first incidence of mastitis on production and economic indicators of primiparous dairy cows

Mastitis is a highly prevalent disease, which negatively affects cow performance, profitability, welfare, and longevity. The objectives of this study were (1) to quantify the impact of the first instance of mastitis, at different stages of lactation, on production and economic performance, and (2) to further quantify the impact of the first instance of mastitis when only cows that remain in the herd for at least 100 d in milk (DIM) and those that remain for 305 DIM are included in the analysis. A retrospective longitudinal study was conducted using data from existing animal health record files and Dairy Herd Improvement records. After editing based on selected inclusion criteria and completeness of health records, data consisted of records from first-lactation Holstein cows, from 120 herds, that calved for the first time between 2003 and 2014, inclusive. Mastitic cows were assigned to 1 of 4 groups based on when in the lactation the first event of mastitis occurred: transition (1-21 DIM), early lactation (22-100 DIM), mid lactation (101-200 DIM), or late lactation (201+ DIM). Mid-lactation and late-lactation mastitic cows were also stratified by cumulative milk yield before the mastitis event. Healthy cows (i.e., no recorded mastitis event) were randomly assigned for each lactation stage, with mid-lactation healthy and late-lactation healthy cows similarly stratified. Production performance (cumulative milk, fat, and protein yield) and economic performance [milk value, margin over feed cost (MOFC), and gross profit] were analyzed using a mixed model with herd as a random effect. Significant losses in cumulative milk yield (-382 to -989 kg) and correspondingly lower fat and protein yields were found in mastitic cows, with transition and late-lactation mastitic cows having the highest losses. Drops in production translated to significant reductions in cumulative milk value (-Can$287 to -Can$591; -US$228 to -US$470), MOFC (-Can$243 to -Can$540; -US$193 to -US$429), and gross profit (-Can$649 to -Can$908; -US$516 to -US$722) for mastitic cows at all stages. Differences between mastitic and healthy cows in the early lactation and transition stages remained for all variables in the 100-DIM analysis, but, aside from gross profit, were nonsignificant in the 305-DIM analysis. Gross profit accounted for all costs associated with mastitis and thus continued to be lower for mastitic cows at all stages, even in the 305-DIM analysis in which culled cows were omitted (-Can$485 to -Can$979; -US$386 to -US$779). The research reflects the performance implications of mastitis, providing more information upon which the producer can make informed culling decisions and maximize both herd profitability and cow longevity.