Effect of level of meat-and-bone meal and pasture type on milk yield and composition of cows grazing tropical pastures

The effects of stocking rate and rate of nitrogen fertilizer application on milk yield from a Gatton panic (Panicum maximum cv. Gatton) pasture were studied over 3 years at Kairi Research Station on the Atherton Tablelands. Thirty-two Friesian cows were used in a 4x2 factorial experiment with treatments 2.0,2.5,3.0 and 3.5 cows/ha, each at 200 and 400 kg N/ha.year. Fat-corrected milk (FCM) yield per cow decreased (P<0.05) with increasing stocking rate according to the equation (� s.e.): Y=3476-276 ( � 111) X (P<0.05), where Y is FCM yield per cow (kg), and X is the stocking rate (cows/ha). FCM yield per hectare increased linearly (Pt0.01) with increasing stocking rate in each year and was represented by the following equations ( � s.e.) for nitrogen applications of 200 and 400 kg/ha.year, respectively: Y = 1584 + 1967 (� 289) X Y = 2366 + 1967 (�289) X (P<0.01), and where Y is FCM yield per hectare (kg) and X is the stocking rate (cows/ha). Milk yield per cow and per hectare were significantly increased by the higher rate of fertilizer application (P<0.01) in year 3, but not in years 1 and 2. Mean FCM yields per cow across years were 2574 and 2858 kg from 200 kg N and 400 kg N pastures respectively (P<0.05). The pasture parameters which were most closely correlated with milk yield were green dry matter (GDM) on offer or its components, namely green leaf and green stem. The relations between FCM yield per cow and green dry matter on offer per cow and per hectare were represented by the equations ( � s.e.): Y = 2211 +0.43 (� 0.12) X1 (P<0.01), And Y= 1656 + 0.35 (�0.08) X2 (P<0.01), where Y is FCM yield per cow (kg/lactation), X1 is GDM per cow (kg) and X2 is GDM per hectare (kg). For this environment, it is concluded that a stocking rate of 2.5 cows/ha with 400 kg N/ ha.year can be safely employed to maintain cows on a pure grass pasture from the opening rains in summer until the end of winter.

Lactation Responses to Sulfur-Containing Amino Acids from Feather Meal or Rumen-Protected Methionine

The present study was conducted to evaluate the effect of commercial exogenous fibrolytic enzyme (EFE) mixture added at 1.5 and 3.0 g (cellulase 4,000 microM glucose/g/h + xylanase 7,990 microM xylose/g/min; 50:50 w/w) per kilogram of dry matter (DM) of feed on nutrient digestibility, milk production, milk composition, and some blood constituents in lactating Murrah buffaloes. Eighteen buffaloes were allotted to three dietary treatments, on the basis of milk yield (8.48, 8.52, and 8.53 kg/day) and days in lactation (68.5, 80.33, and 82.00) for 90 days. The buffaloes were fed a total mixed ration (TMR) comprising of 45% chaffed wheat straw, 15% chopped green maize, and 40% concentrate on DM basis (control group), the same TMR plus EFE at 1.5 g/kg DM (T-1 group) and the same TMR plus EFE at 3.0 g/kg DM (T-2 group) supplemented through the concentrate mixture. There was no effect of fortifying EFE mixture on DM intake and crude protein intake (grams per day) whereas total digestible nutrients intake (kilogram per day) was higher by (P < 0.05) 12.53% in T-1 group over that of control, and there was no significant difference between T-2 and control groups. The average daily milk yield and 4% fat-corrected milk (FCM) yield was higher (P < 0.05) by 12.99% and 15.17% in T-1 group as over that of control, and there was no difference between T-2 and control groups. There was no (P > 0.05) difference in blood glucose and blood urea nitrogen concentration in different experimental groups. It is concluded that supplementation of cellulase and xylanase mixture at 1.5 g/kg of DM of TMR containing wheat straw (45%), green maize (15%), and concentrate (40%) on DM basis significantly increased (P < 0.05) the average daily milk yield and FCM yield in Murrah buffaloes due to improved dietary fiber digestion.

Brown midrib corn silage (BMRS) is used as an alternative to conventional corn silage (CS) to increase milk yield because of its higher neutral detergent fibre digestibility (NDFD) and DM intake (DMI). Forty Holstein dairy cows were used in a completely randomised design with a 2 × 2 factorial arrangement. Two groups of 13 cows in early lactation (EL) and 7 in late lactation (LL) were fed with a total mixed ration including brown midrib (BMR) or conventional corn silage (C), for a period of 42 days. The cows were milked twice a day, milk yield and DMI were recorded, and NDFD was estimated. Milk composition was measured twice a week and milk fatty acid profile was quantified on the final week of the experiment. In EL, BMR diet increased DMI, NDFD, milk and protein yield whereas milk fat content and yield were decreased. Concentrations of trans-10 C18:1 and trans-10, cis-12 C18:2 in milk were higher in BMR. In LL cows DMI was similar between BMR and C whereas milk and fat yields tended to be higher in C. Fat-corrected milk yield was greater in the C diet. The effect of the BMRS on DMI and milk yield depended on stage of lactation, justifying its use in early lactation. The lower milk fat concentration, observed when BMRS was included in the diets, could be explained in part by an increased concentration of trans-10 C18:1 and trans-10, cis-12 C18:2.

An economic evaluation was conducted to assess the impact of different feeding regimes on milk production and overall profitability in lactating Murrah buffaloes. The study involved eighteen buffaloes in their 1st to 2nd lactation stage at the buffalo farm of the Department of Livestock Production Management, College of Veterinary Sciences, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, India. Three dietary treatment groups (T1, T2, and T3) were established using a factorial completely randomized design. The control group (T1) received a diet comprising 30% wheat straw, 35% green fodder, and 35% concentrate mixture on a dry matter basis, following ICAR (2013) standards. Treatment groups T2 and T3 received similar diets, with varying proportions of crude protein and total digestible nutrients (CP and TDN) from green fodder replaced with concentrate mixture. Data collection included parameters such as feed intake, milk yield, milk fat percentage, and 6% fat-corrected milk (FCM) yield. Economic evaluation encompassed feed costs per kilogram of milk yield and 6% FCM yield per animal. Statistical analysis employed ANOVA, with the Duncan Multiple Range Test utilized for mean comparisons. Results indicated that buffaloes in treatment groups T2 and T3 exhibited higher dry matter intake, milk yield, and 6% FCM yield compared to the control group (T1). However, milk fat percentage remained consistent across all treatment groups. The economic analysis revealed that despite higher total feeding costs for T2 and T3, the feed cost per kilogram of milk yield and 6% FCM yield were lower in these treatment groups compared to the control group (T1). In conclusion, replacing 30% or 40% of CP and TDN of green fodder with a concentrate mixture in the diets of lactating Murrah buffaloes resulted in increased milk production and improved economic viability. These findings underscore the potential benefits of optimizing feeding regimes to enhance milk yield and profitability in dairy farming. Further research could explore other aspects of feeding strategies and their economic implications in the context of dairy production.

This study was conducted to determine the effects of heat treated-soybean meal, fish meal, meat meal, and an equal blend of fish and meat meal as rumen-ungradable protein (RUP) sources on productive performance, nutrient digestibility, N-utilization efficiency, and blood metabolites in high-producing Holstein dairy cows. Twelve lactating Holstein cows (DIM = 89 ± 11; mean ± SD) were used in a replicated 4 × 4 Latin square design receiving four diets formulated with amounts (DM basis): (1) 3.1% heat treated-soybean meal (T-SBM), (2) 2.5% fish meal (FM), (3) 3.0% meat and bone meal (MM), and (4) an equal blend of 1.4% FM plus 1.4% MM (FMM), as dietary RUP sources. The crude protein concentration was kept constant across the treatments (16.7% of DM). The duration of each experimental period was 21 d with 15 d devoted to dietary adaptation and 6 d to data collection. Dry matter intake (24.2 kg/d), actual milk (41.8 kg/d), 4% fat-corrected milk yield (35.6 kg/d), milk composition (Fat = 3.03%, Protein = 2.90%), and blood metabolites were not affected by treatments. Apparent N efficiency (29.5%) was similar across the diets. Based on our results, T-SBM, FM, MM, and mixed of FM and MM had a similar effect on productivity and N-utilization efficiency in lactating dairy cows. Based on the income over feed cost (IOFC), under our experimental conditions, use of the meat meal as a source of dietary RUP can be recommended as a feeding strategy for feed to lactating cows receiving high-concentrate diets.

We evaluated the effects of supplementing bacterial direct-fed microbial (DFM) on performance, apparent total-tract digestibility, rumen fermentation, and immune parameters of lactating dairy cows. One hundred fourteen multiparous Holstein cows (41 ± 7 DIM) were used in a randomized complete block design with an experiment comprising 14 d of a covariate (pre-experimental sample and data collection) and 91 d of an experimental period. Cows were blocked based on energy-corrected milk (ECM) yield during the covariate period and the following treatments were randomly assigned within each block: (1) control (CON), corn silage-based total mixed ration without DFM; (2) PRO-A, basal diet top-dressed with a mixture of Lactobacillus animalis and Propionibacterium freudenreichii at 3 × 109 cfu/d; and 3) PRO-B, basal diet top-dressed with a mixture of L. animalis, P. freudenreichii, Bacillus subtilis, and Bacillus licheniformis at 11.8 × 109 cfu/d. Milk yield, dry matter intake (DMI), and body weight were measured daily, while milk samples for component analysis were taken on 2 consecutive days of each week of data collection. Feces, urine, rumen, and blood samples were taken during the covariate period, wk 4, 7, 10, and 13 for estimation of digestibility, N-partitioning, rumen fermentation, plasma nutrient status and immune parameters. Treatments had no effect on DMI and milk yield. Fat-corrected milk (3.5% FCM) and milk fat yield were improved with PRO-B, while milk fat percent and feed efficiency (ECM/DMI) tended to increase with PRO-B compared with PRO-A and CON. Crude fat digestibility was greater with PRO-B compared with CON. Feeding CON and PRO-A resulted in higher total volatile fatty acid concentration relative to PRO-B. Percentage of neutrophils tended to be reduced with PRO-A compared with CON and PRO-B. The mean fluorescence intensity (MFI) of anti-CD44 antibody on granulocytes tended to be higher in PRO-B compared with CON. The MFI of anti-CD62L antibody on CD8+ T cells was lower in PRO-A than PRO-B, with PRO-A also showing a tendency to be lower than CON. This study indicates the potential of DFM to improve fat digestibility with consequential improvement in fat corrected milk yield, feed efficiency and milk fat yield by lactating dairy cows. The study findings also indicate that dietary supplementation with DFM may augment immune parameters or activation of immune cells, including granulocytes and T cells; however, the overall effects on immune parameters are inconclusive.

Short Communication: Effects of 2-Hydroxy-4-(Methylthio) Butanoic Acid Isopropyl Ester on Milk Production and Composition of Lactating Holstein Dairy Cows

When Should Lactating Dairy Cows Reach Positive Energy Balance?

The effect of systematic and continuous environmental factors on 4% fat corrected milk (FCM) yield in 2805 Simmental cows over whole and standard lactations was evaluated using the general linear model. The test systematic or fixed factors included the effect of farm or breeding area, calving season, year of birth, season of birth, lactation group and interactions between year of birth and season of birth, breeding area and calving season, and breeding area and lactation group. The continuous factor analysed was the effect of age at first conception. The effect of breeding area, lactation group and calving season on 4%FCM yield over whole and standard lactations was found to be very highly significant (P<0.001). The interactions of fixed i.e. systematic factors involved in the model, including those between year and season of birth, breeding area and calving season, and farm and lactation group had a very highly significant effect (P<0.001) on 4% FCM yield over both whole and standard lactations. The age at first conception, as a continuous factor, showed a very highly significant effect (P<0.001) on 4% FCM yield over both whole and standard lactations. The model used to correct the 4%FCM yield over whole and standard lactations for the effect of systematic factors was very highly significant (P<0.001). The variance of the model accounted for 15.93% and 21.55% of the total variance in 4% FCM yield over whole and standard lactations, respectively. The resulting coefficient of determination (R2) in 4% FCM yield was 0.159 over whole lactations and 0.216 over standard lactations.

The effect of applying 50 kg N ha-I in autumn and winter each year on milk yield of Friesian cows and dry matter yield and botanical composition of a green panic (Panicum maximum var, trichog1ume)- glycine (Glycine wightii cv. Tinaroo) pasture was measured over two years on the Atherton Tableland, north Queensland. Pastures were grazed at 1.3, 1.6, 1.9 and 2.5 cows ha-1. Milk yield and pasture yield were increased by nitrogen fertilization, particularly at the high stocking rates (P &lt; 0.05). Increases in milk yield from mid-autumn to spring almost totally accounted for increases in annual milk production. Nitrogen fertilizer did not decrease the yield of legume, but legume content of the pasture was reduced in the second year (P &lt; 0.01). Response by non-leguminous species to nitrogen increased (P &lt; 0.05) with stocking rate, a change associated with decreasing legume contents of the pastures. Average fat corrected milk (FCM) yield per cow from mid-autumn to spring was restricted by less than 1600 kg pasture D.M. on offer cow-I or 2500 kg D.M. ha-1. When compared at the same dry matter yields, FCM yield was always higher from nitrogen fertilized pastures than from pastures not recieving fertilizer nitrogen.

Effects of long daily photoperiod and bovine somatotropin (Trobest) on milk yield in cows.

The experiment was designed to assess the effect of supplemental feeding of 40 g/day rumen-protected choline (33.5% w/w) in the total mixed ration of lactating cows on nutrient intake, lactation, reproduction, feed efficiency, and feed cost during 294 days of the lactation. The study was conducted at Livestock Research Station, Anand during 2018 to 2021. A total of sixteen cows were randomly distributed into two groups of eight each based on descending order of previous standard lactation yield and lactation numbers. An intake and milk yield were calculated for 1-21 biweekly periods. The milk composition was assessed four times during lactation. The body condition score (BCS) on a 1-5 point scale with an increment of 0.25 points was measured at -21, -14, -7, 0, 7, 14, 21, 35, 49, 63, 91, and 119 days of calving. The supplemental feeding of rumen-protected choline (RPC) in T2 group resulted in lower nutrient intake, lesser insemination to conceive, and service period with higher 4% fat corrected milk (FCM) yield in dairy cows. The body condition score and milk yield persistency were higher along with improved feed efficiency and feed economics in the T2 group as compared to the T1 group. The daily feeding of 40 g RPC during -21 to 120 days of calving resulted in significantly lower nutrient intake with improved 4% FCM yield, reproductive performance, feed efficiency, and feed economics in dairy cows.

1. Two experiments were carried out with lactating Friesian cows with a potential for high milk production. Within 3 d after calving they were fitted with a catheter to allow infusions to be given into the abomasum. During each experiment the milk yields and intake of the cows were such that they were calculated to be in negative energy balance.2. In the first experiment three cows were infused daily with 10 l, the infusate being water, a suspension providing 300 g casein, or a solution providing 300 g glucose. The cows were offered a diet of barley straw, rolled barley and ureaad lib.during the first 60 d, after which they were fed to a calculated yield of 7 kg fat-corrected milk (FCM) less than their previous yield to ensure a negative energy balance. Infusion of casein increased yield by up to 3 kg FCM in comparison with glucose or water infusion. It also increased the concentration of crude protein in milk by approximately 13%. There was no consistent effect on milk fat concentration.3. In the second experiment four cows were used in a trial of Latin-Square design. The basal ration was sufficient for a yield of 10 kg FCM/d. Four levels of casein and glucose infused into the abomasum daily were (g) 0, 750; 250, 500; 500, 250; 750, 0. The yields of FCM (kg/d) were 18.9, 22.7, 25.2 and 26.1, the concentration of protein (g/kg) was 25.2, 28.4, 29.6 and 31.5 and the concentration of milk fat (g/kg) was 48.2, 49.8, 51.0 and 54.8 for the four treatments respectively. In each instance the increases in values obtained with increasing level of casein infusion were significant. Infusion of casein was calculated to increase the extent of net energy deficit from 20.5 to 41.0 MJ/d. The possible protein limitations for cows in negative energy balance were discussed.

Twenty lactating cows were used over two growing seasons to compare three complete feeds containing corn silage, alfalfa grass silage or ground hay, with long hay as the control. The roughage to concentrate ratio was 6:4 in experiment 1, and 4:6 in experiment 2. There were no significant (P &lt; 0.05) differences m dry matter and total digestible nutrient (TDN) intake among roughage sources except for corn silage in experiment 1. The molar percentage of acetic, butyric, valeric, isobutyric and isovaleric and the molar proportion of acetic to propionic were not affected (P &lt; 0.05) by different sources of roughage. In experiment 1, TDN, dry matter, crude protein and nitrogen-free extract (NFE) digestibility was lower (P &lt; 0.05) for the corn silage diet. However, in experiment 2 there were no significant differences (P &lt; 0.05) in TDN, dry matter, crude protein and NFE digestibility among the experimental treatments. Blood glucose and urea concentrations were not affected by roughage sources. The mean daily (experiment 1) milk yields of cows fed long and ground hay mixtures were greater (P &lt; 0.05) than those of cows fed the alfalfa grass silage mixture; however, the mean daily fat-corrected milk (FCM) yield was not affected (P &lt; 0.05) by the source of roughage (experiment 1). The mean daily milk yield and FCM yield were not affected significantly (P &lt; 0.05) by roughage source (experiment 2). The percentage of milk fat, and solids-not-fat, were not influenced (P &lt; 0.05) by roughage source (experiments 1 and 2). Roughage source appeared to have little effect on molar ratios of fatty acids found in the milk fat.