Fat-corrected Milk Research Articles

Fresh cassava root replacing cassava chip could enhance milk production of lactating dairy cows fed diets based on high sulfur-containing pellet

The experiment objective was to assess the shifting effect from cassava chip (CC) to fresh cassava root (FC) affected feed utilization, rumen metabolism, cyanide-using bacteria, and milk quality in lactating Thai Friesian dairy cows fed diets based on high sulfur-containing pellet (PS). Four lactating Thai Friesian dairy cows of 481.5 ± 31.3 kg BW (about 4 years old were allocated with four treatments in a 4 × 4 Latin square design. The four treatments were: replacement FC for CC at 0%, 60%, 80%, and 100% dry matter (DM), respectively. Feed intakes for four diets in terms of total dry matter intake (kg/day and % BW) was linearly correlated with levels of replacement of FC (p < 0.01). Digestibilities of crude protein (CP), DM, organic matter (OM), amylase-treated neutral detergent fiber (aNDF), and acid detergent fiber (ADF) did not change with increasing levels of FC in the diet (p > 0.05). Moreover, the total bacterial counts and cyanide population utilizing bacteria cubically increased with an increase of FC replacement (p < 0.01). The effect of CC substitution with FC in the PS diet was cubically increased on blood thiocyanate concentrations (p < 0.01). In addition, the propionate (C3) concentration at 0 and 4 h post-feeding changed significantly among treatments (p < 0.01), which were linearly improved with an increasing dose of replacement FC and were highest when FC was replaced at 100%. The yield of 3.5% fat-corrected milk was high in the treatment with the replacement of FC as compared to the control (p < 0.01). The yield of fat and milk fat percentages was high (p < 0.01) in the group with the replacement of FC as compared to feed with no diet replaced. The milk thiocyanate concentration was cubically enhanced when levels of FC replacement increased (p < 0.01) and was the highest when FC was replaced at 100%. As the amount of FC replacement was raised, the somatic cell count in the milk decreased linearly (p < 0.01). In conclusion, the replacement of FC at 100% in PS could enhance the feed intake, microbial populations, total volatile fatty acid (VFA), C3 concentration, milk yield, and milk quality.

Replacement of soybean meal with alternative protein sources in the concentrate supplement for lactating Holstein × Gyr cows in an intensive tropical pasture-based system: Effects on performance, milk composition, and diurnal ingestive behavior

The purpose of this study was to evaluate the effects of total replacement of soybean meal (SBM) with three alternative protein sources in the concentrate supplement on performance, feed efficiency, milk composition, and diurnal ingestive behavior of Holstein × Gyr cows under an intensive system of grazing on tropical pasture. Twelve cows with 512 ± 61 kg of BW (mean ± standard deviation), 20.4 ± 4.14 kg/d of milk yield, and 86 ± 40 days in milk were distributed in a triplicated 4 × 4 Latin square design. The treatments consisted of four concentrate supplements formulated with SBM (Control), cottonseed meal (CSM), peanut meal (PM), or sunflower meal (SFM). The animals were kept in intensive rotational grazing (n = 24 paddocks) on Tanzania grass (Panicum maximum syn. Megathyrsus maximus) pasture, with 1 day of occupation per paddock and a stocking rate of 4.3 AU/ha. The daily amount of concentrate supplement offered to the cows was 1 kg DM of concentrate per 3 kg of milk produced. Fat-corrected milk yield (FCM) for the SBM group (21.1 kg/d) was similar to that of the other groups (21.5 kg/d on average); however, milk fat content and milk urea nitrogen were lower in the SBM group (36 g/kg and 12.6 mg/dL) than in the PM group (38.4 g/kg and 14.2 mg/dL). The protein source did not affect the intakes of DM (17.14 kg/d on average) and forage (9.66 kg DM/d on average). However, cows fed CSM had a lower concentrate supplement intake compared to those fed PM (7.11 vs. 7.78 kg DM/d). The lowest and the highest ether extract intake levels were observed in cows fed with SBM (0.31 kg/d) and CSM (0.39 kg/d). No effect of the protein source was detected on the time spent on grazing, rumination, and idleness, with mean values of 4.73, 2.01, and 5.26 h within a 12 h observation period (06:00–18:00 h). Soybean meal can be replaced with CSM, PM, or SFM in the concentrate supplement without affecting the FCM, feed intake, feed efficiency, and diurnal ingestive behavior of lactating Holstein × Gyr cows in an intensive tropical grazing system. The replacement of SBM with PM is recommended since the latter promotes the best results in terms of milk fat content.

Production, metabolism, and follicular dynamics in multiparous dairy cows fed diets providing different amounts of metabolizable protein prepartum and postpartum

Our objectives were (1) to determine whether increasing metabolizable protein (MP) supply above requirements in late-gestation cows would benefit health, milk production, and reproduction; (2) to determine whether an increased supply of MP postpartum affects production; and (3) to determine whether supply of MP prepartum interacts with MP supply postpartum. Pregnant nonlactating cows (n = 60) blocked by expected parturition date were assigned to 1 of 3 prepartum diets from 21 d prepartum to parturition: 12% crude protein (CP) soybean meal (SBM) supplement (LSB); 15% CP SBM supplement (HSB); and 15% CP SBM plus animal-marine protein supplement (HMP). Diets were formulated to supply an estimated 924, 988, and 1,111 g/d of MP, respectively, at 11.5 kg of dry matter intake (DMI). After parturition, cows received diets containing 18% CP, either from SBM (SB) or SBM plus animal-marine protein (AMP) supplements, that provided 2,056 (SB) or 2,293 g/d (AMP) of MP at 21 kg of DMI; thus, treatments were in a 3 × 2 factorial arrangement. Milk production and DMI were recorded for 63 d postpartum. Prepartum DMI was lower at wk -3 for cows fed LSB compared with those fed HSB or HMP. Postpartum DMI did not differ significantly between cows fed SB and those fed AMP (20.8 vs. 19.6 kg/d). Milk production did not differ due to prepartum diets or postpartum diets. Milk fat and protein percentages were not affected by prepartum or postpartum diets. Cows fed AMP postpartum tended to produce more milk fat, but 4% fat-corrected milk (FCM) did not differ from SB-supplemented cows (33.6 kg/d vs. 32.2 kg/d). Gross feed efficiency (FCM/DMI) was greater for cows fed AMP postpartum (1.82 vs. 1.68). Prepartum concentrations of urea N in plasma were lower for LSB than for HSB and HMP, and HSB was greater than HMP. Postpartum concentrations of nonesterified fatty acids and β-hydroxybutyrate were greater for cows fed AMP postpartum than for those fed SB. Postpartum urea N was higher for SB than for AMP (14.4 vs. 12.5 mg/dL). Concentration of total protein in plasma was greater postpartum for cows fed HSB or HMP prepartum than for those fed LSB, and was greater postpartum for cows fed AMP than for those fed SB. Hepatic concentrations of total lipids and triglyceride did not differ among treatments. Hepatic glycogen was greater postpartum for cows fed SB postpartum. Feeding HSB or HMP increased the number of follicles 6 to 9 mm in diameter compared with LSB. The size of the largest follicle was increased by HMP compared with HSB. In conclusion, increasing the amount of MP fed to cows during the last 21 d prepartum did not affect milk production or BCS but increased plasma total protein concentration. Follicular dynamics were improved by increasing the amount of MP prepartum. Feeding HMP prepartum improved follicular dynamics prepartum and increased milk fat yield in wk 1. Feeding AMP postpartum increased efficiency of FCM production and plasma total protein. We found few interactions between prepartum and postpartum MP supply.

Study of feed efficiency based on residual feed intake and 4% fat-corrected milk in Iranian lactating Holstein dairy cows

Study of feed efficiency based on residual feed intake and 4% fat-corrected milk in Iranian lactating Holstein dairy cows

Novel Process Methods for the Whole Cottonseed: Effect on the Digestibility, Productivity, Fat Profile, and Milk Gossypol Levels in Lactating Dairy Cows.

In this study, we aimed to determine the effect of mixed-process methods on the ruminal degradability of whole cottonseed (WCS) both in situ and in vitro, and the effect on the production performance of dairy cows. Eight WCS process methods were tested on the ruminal digestibility, including crush-alkali 1 (CA1), crush-alkali 2 (CA2), crush-alkali 3 (CA3), alkali 1-crush (A1C), alkali 2-crush (A2C), alkali 3-crush (A3C), crush-only (CO), and non-processed. Alkali 1, 2, and 3 indicate the supplementation of alkali to WCS at the dose of 4% on dry matter (DM) base as followed: 4% NaOH, 2% NaOH + 2% CaO, and 2% NaOH + 2% CaCl2 alkaline, respectively. Among all treatments, CA2 showed the highest WCS ruminal degradation in situ and the highest intestinal digestibility of WCS in vitro. Furthermore, an animal experiment was conducted for 60 days on 30 Holstein dairy cows, using a diet without WCS (CON group), a diet containing 8% non-processed WCS (NP group), and a diet containing 8% CA2-treated WCS (CA2 group). The results indicated that the dry matter intake, 4% fat-corrected milk production, milk protein, milk fat, and content of short-chain saturated fatty acid of milk in the CA2 group were significantly higher (P < 0.05) than CON group. Furthermore, DMI, the CLA was significantly greater (P < 0.05) in the CA2 group than the other groups. Additionally, the free gossypol concentration in serum or milk was under safety level in the three groups. Overall, crush and alkalization (NaOH: CaO = 1:1) treatment could improve the utilization of WCS in dairy farms.

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.

Abomasal infusion of different exogenous emulsifiers alters fatty acid digestibility and milk fat yield of lactating dairy cows

We evaluated the effects of abomasal infusion of emulsifiers on fatty acid (FA) digestibility and milk production of lactating dairy cows. All emulsifiers examined were polysorbates, nonionic surfactants, consisting of a polyethoxylated sorbitan esterified with FA. The polysorbates tested in this study consisted of the same polyethoxylated sorbitan base but differed by the FA esterified to it. Eight rumen-cannulated multiparous cows (89 ± 13 d in milk) were assigned to a treatment sequence in 4 × 4 Latin squares with 18-d periods consisting of 7 d of washout and 11 d of infusion. Treatments were abomasal infusions of water only (CON) or 30 g/d of different emulsifiers as follows: polysorbate-C16:0 (T40), polysorbate-C18:0+C16:0 (T60), and polysorbate-C18:1 (T80). Emulsifiers were dissolved in water and delivered at 6-h intervals (total daily infusion was divided into 4 equal infusions per day). Cows were fed the same diet that contained (% diet dry matter) 32.1% neutral detergent fiber, 15.7% crude protein, 25.8% starch, and 3.32% FA (including 1.92% FA from a saturated FA supplement containing 34.2% C16:0 and 47.7% C18:0). The T80 treatment increased total FA digestibility compared with CON (5.40 percentage units) and T60 (3.90 percentage units) and tended to increase it compared with T40. Also, T40 tended to increase and T80 increased (4.80 percentage units) 16-carbon FA digestibility compared with CON. The T80 treatment increased 18-carbon FA digestibility compared with the other treatments. The T40 treatment tended to increase and T80 increased total FA absorption compared with CON (53 g/d) and T60 (52 g/d). Both T40 and T80 increased the absorption of 16-carbon FA compared with CON and T60. The T60 treatment did not differ from CON for any digestibility variable. Both T40 and T80 increased the yields of milk fat, 3.5% fat-corrected milk, and de novo, mixed, and preformed milk FA compared with CON. In conclusion, not all emulsifiers increased FA digestibility. Compared with CON, T80 increased the digestibility and absorption of total, 16-, and 18-carbon FA. The T40 treatment tended to increase and T80 increased total FA absorption and the yields of milk fat and 3.5% FCM compared with CON. Milk fat yield was increased by increases in de novo, mixed, and preformed milk FA. In our short-term infusion study, results suggest that the predominant FA present in the polysorbate affects its ability to improve FA digestibility. Overall, FA digestibility and absorption were improved the most when cows received the T80 treatment.

Effect of Heat Waves on Some Italian Brown Swiss Dairy Cows' Production Patterns

Climate change is impacting worldwide efficiency and welfare standards in livestock production systems. Considering the sensibility to heat stress reported for different milk production patterns in Italian Brown Swiss, this study aims to evaluate the effect of heat waves (HWs)of different lengths on some milk production traits (fat-corrected milk, energy-corrected milk, protein and fat yield, protein percentage, cheese production at 24 h, and cheese yield). A 10-year dataset (2009–2018), containing 202,776 test-day records from 23,296 Brown Swiss cows, was used. The dataset was merged both with the daily maximum temperature–humidity index (THI) recorded by weather stations and with the daily maximum THI threshold for each trait in Italian Brown Swiss cows. The study considered 4 different HWs according to their length: 2, 3, 4, and 5 consecutive days before the test-day over the weighted THI threshold. Milk production traits were determined as the difference in losses compared to those after only 1 day before the test-day over the weighted maximum THI. All traits showed to be affected by HWs. Particularly, protein percentage losses increased from −0.047% to −0.070% after 2 consecutive days over the daily THI threshold, reaching −0.10% to −0.14% after 5 days (p &amp;lt; 0.01), showing a worsening trend with the increasing length of HWs. First parity cows showed to be more sensitive to HWs than other parity classes, recording greater losses after shorter HWs, compared to multiparous cows, for protein yield and, consequently, for cheese production at 24 h. This suggests a less efficient metabolic response to heat stress and exposure time in primiparous, compared to multiparous cows, probably due to their incomplete growth process that overlaps milk production, making it more difficult for them to dissipate heat. Although actions to mitigate heat stress are always needed in livestock, this study points out that often time exposure to warm periods worsens milk production traits in Brown Swiss cows.

Acremonium terricola Culture's Dose-Response Effects on Lactational Performance, Antioxidant Capacity, and Ruminal Characteristics in Holstein Dairy Cows.

Acremonium terricola culture (ATC) has similar bioactive constituents to Cordyceps and is known for its nutrient and pharmacological value, indicating the potential of ATC as a new feed additive in dairy cow feeding. The primary aim of this experiment was to investigate the effects of increasing amounts of ATC in diets on milk performance, antioxidant capacity, and rumen fermentation, and the secondary aim was to evaluate the potential effects of high doses of ATC. A total of 60 multiparous Holstein cows (110 ± 21 days in milk; 2.53 ± 0.82 parity) were assigned into 15 blocks and randomly assigned to one of four groups: 0, 30, 60, or 300 g/d of ATC per cow for 97 days. Data were analyzed using repeated measures in the Mixed procedure. Dry-matter intake was not changed (p > 0.05), while energy-corrected milk and fat-corrected milk yields increased linearly and quadratically, and somatic cell count in milk decreased linearly and quadratically (p < 0.05). The lactation efficiency and the yields of milk fat and protein increased linearly (p < 0.05). On day 90, serum catalase level, total oxidative capacity, glutathione peroxidase, immunoglobulin A, and immunoglobulin M concentrations were significantly higher in the 60 and 300 g/d groups than in the 0 g/d group (p < 0.05). ATC addition showed linear effects on total volatile fatty acid (VFA), acetate, branched VFA concentrations, and rumen pH (p < 0.05). Supplementing 60 and 300 g/d ATC significantly affected the bacterial composition (p < 0.05). The relative abundance of Christensenellaceae_R–7_group and Lachnospiraceae_NK3A20_group were significantly increased by 60 g/d supplementation, and the relative abundance of Erysipelotrichaceae_UCG_002, Acetitomaculum, Olsenella, and Syntrophococcus were significantly increased by 300 g/d supplementation (p < 0.05). ATC was effective in enhancing rumen fermentation and reducing somatic cell count in milk, thereby improving milk yield. The optimized dose of ATC was 60 g/d for lactating cows, and there were no risks associated with high doses of ATC.

Effects of calcium ammonium nitrate fed to dairy cows on nutrient intake and digestibility, milk quality, microbial protein synthesis, and ruminal fermentation parameters

We evaluated the effects of supplemental calcium ammonium nitrate (CAN) fed to dairy cows on dry matter (DM) intake, nutrient digestibility, milk quality, microbial protein synthesis, and ruminal fermentation. Six multiparous Holstein cows at 106 ± 14.8 d in milk, with 551 ± 21.8 kg of body weight were used in a replicated 3 × 3 Latin square design. Experimental period lasted 21 d, with 14 d for an adaptation phase and 7 d for sampling and data collection. Cows were randomly assigned to receive the following treatments: URE, 12 g of urea/kg of DM as a control group; CAN15, 15 g of CAN/kg of DM; and CAN30, 30 g of CAN/kg of DM. Supplemental CAN reduced DM intake (URE 19.0 vs. CAN15 18.9 vs. CAN30 16.5 kg/d). No treatment effects were observed for apparent digestibility of DM, organic matter, crude protein, ether extract, and neutral detergent fiber; however, CAN supplementation linearly increased nonfiber carbohydrate digestibility. Milk yield was not affected by treatments (average = 23.1 kg/d), whereas energy-corrected milk (ECM) and 3.5% fat-corrected milk (FCM) decreased as the levels of CAN increased. Nitrate residue in milk increased linearly (URE 0.30 vs. CAN15 0.33 vs. CAN30 0.38 mg/L); however, treatments did not affect nitrite concentration (average: 0.042 mg/L). Milk fat concentration was decreased (URE 3.39 vs. CAN15 3.35 vs. CAN30 2.94%), and the proportion of saturated fatty acids was suppressed by CAN supplementation. No treatment effects were observed on the reducing power and thiobarbituric acid reactive substances of milk, whereas conjugated dienes increased linearly (URE 47.6 vs. CAN15 52.7 vs. CAN30 63.4 mmol/g of fat) with CAN supplementation. Treatments had no effect on microbial protein synthesis; however, molar proportion of ruminal acetate and acetate-to-propionate ratio increased with CAN supplementation. Based on the results observed, supplementing CAN at 30 g/kg of DM should not be recommended as an optimal dose because it lowered DM intake along with ECM and 3.5% FCM, although no major changes were observed on milk quality and ruminal fermentation.

Effect of dietary supplementation or cessation of magnesium-based alkalizers on milk fat output in dairy cows under milk fat depression conditions

We aimed to evaluate the effects of dietary supplementation with magnesium oxide and calcium-magnesium dolomite on milk fat synthesis and milk fatty acid profile or persistency in milk fat synthesis after their cessation in dairy cows under milk fat depression conditions. Twenty-four multiparous dairy cows in early lactation (mean ± standard deviation; 112 ± 14 d in milk) were used in a randomized complete block design. Milk fat depression was induced in all cows for 10 d by feeding a diet containing 35.2% starch, 28.7% neutral detergent fiber, and 4.8% total fatty acid (dry matter). The experiment was conducted in 2 periods. During the Mg-supplementation period (d 1-20), cows were randomly assigned to (1) the milk fat depression diet used during the induction phase (control; n = 8), (2) the control diet plus 0.4% magnesium oxide (MG; n = 8), or (3) the control diet plus 0.8% calcium-magnesium dolomite (CMC; n = 8). Compared with the control group, feeding the magnesium-supplemented diets increased milk fat concentration and yield by 12% within 4 d. During the 20-d Mg-supplementation period, both the MG and CMC diets increased milk fat concentration and yield, as well as 3.5% fat-corrected milk and energy-corrected milk yield, without affecting dry matter intake, milk yield, and milk protein and lactose concentrations. In the Mg-cessation period (d 21-30), all cows received the control diet, which resulted in a greater milk fat concentration and yield in the cows that had already received the MG and CMC diets in the Mg-supplementation period. Whereas, milk fat concentration and yield remained high after discontinuation of the magnesium-containing alkalizer until d 27. The difference in milk fat synthesis was associated with lower trans-10 C18:1 (-22%) and higher trans-11 C18:1 (+12.5%) concentrations in milk during the Mg-supplementation period. Furthermore, it was evident that within 2 d of supplementation, the trans-10:trans-11 ratio was lower in MG and CMC cows compared with cows receiving the control. This suggested that the effect of magnesium-based alkalizers on milk fat synthesis was mediated via a shift in ruminal biohydrogenation of cis-9,cis-12 C18:2 in the rumen. In conclusion, abrupt addition of magnesium oxide and calcium-magnesium dolomite increased milk fat synthesis, which persisted for 7 d after cessation of magnesium-based alkalizers. A similar ability to recover milk fat synthesis and normal fatty acid biohydrogenation pathways was observed for magnesium oxide and calcium-magnesium dolomite.

Effect of prepartum dietary-cation anion difference on performance, blood mineral and metabolite concentrations in Holstein dairy cows

Dietary cation-anion difference (DCAD) initiates a compensatory metabolic acidosis, which improves calcium (Ca) absorption and mobilization before calving and minimizes clinical and subclinical hypocalcaemia after calving. The goal of this study was to evaluate how mineral concentrations, blood metabolites, parathyroid hormone (PTH), and productive performance were affected by prepartum dietary cation-anion difference (DCAD mEq [(Na + K – Cl + S)]/kg of dry matter (DM)) in postpartum dairy cows. Forty-eight multiparous Holstein cows ranging from 2 to 5 lactations with an average body weight of 685 ± 10 kg (mean ± SD) were allocated in a randomized block design with three prepartum diets differing in DCAD (0, –100, and –180 mEq/ kg DM). All cows were fed the same postpartum diet and kept on trial for 66 days. Cows fed –180 and –100 mEq DCAD had greater prepartum non-esterified fatty acid (NEFA) concentrations than cows fed 0 mEq DCAD. Cows fed –180 mEq DCAD had greater serum Ca concentrations than cows fed –100 and 0 mEq DCAD. PTH concentrations were greater in cows fed 0 mEq DCAD than in cows fed –100 or –180 mEq DCAD. Cows fed 0 mEq DCAD had higher milk protein and solid-not-fat (SNF) levels than cows fed –100 or –180 mEq DCAD. Treatment and interaction had no effect on milk yield, 3.5% fat-corrected milk (FCM), energy-corrected milk (ECM), milk fat, total solids (TS), lactose, milk urea nitrogen (MUN), magnesium (Mg), sodium (Na), chloride (Cl), potassium (K), beta hydroxybutyric acid (BHBA), and liver or kidney functions. We concluded that adding anionic salts to dairy cows’ diets (–100 and –180 mEq DCAD) improved postpartum Ca availability and reduced clinical and subclinical hypocalcaemia while having no effect on milk yield or fat-corrected milk.

Lactational performance of dairy cows in response to supplementing N-acetyl-l-methionine as source of rumen-protected methionine

The objective of this experiment was to evaluate the effects of supplementing a rumen-protected source of Met, N-acetyl-l-methionine (NALM), on lactational performance and nitrogen metabolism in early- to mid-lactation dairy cows. Sixty multiparous Holstein dairy cows in early lactation (27 ± 4.3 d in milk, SD) were assigned to 4 treatments in a randomized complete block design. Cows were blocked by actual milk yield. Treatments were as follows: (1) no NALM (control); (2) 15 g/d of NALM (NALM15); (3) 30 g/d of NALM (NALM30); and (4) 45 g/d of NALM (NALM45). Diets were formulated using a Cornell Net Carbohydrate and Protein System (CNCPS) v.6.5 model software to meet or exceed nutritional requirements of lactating dairy cows producing 42 kg/d of milk and to undersupply metabolizable Met (control) or supply incremental amounts of NALM. The digestible Met (dMet) supply for control, NALM15, NALM30, and NALM45 were 54.7, 59.8, 64.7, and 72.2 g/d, respectively. The supply of dMet was 88, 94, 104, and 115% of dMet requirement for control, NALM15, NALM30, and NALM45, respectively. Milk yield data were collected, dry matter intake (DMI) was measured daily, and milk samples were collected twice per week for 22 wk. Blood, ruminal fluid, urine, and fecal samples were collected during the covariate period and during wk 4, 8, and 16. Data were analyzed using the GLIMMIX procedure of SAS (SAS Institute) using covariates in the model for all variables except body weight. Linear, quadratic, and cubic contrasts were also tested. Treatments did not affect DMI, milk yield, and milk component concentration and yield; however, feed efficiency expressed as milk yield per DMI and 3.5% fat-corrected milk per DMI were quadratically affected, with greater response observed for NALM15 and NALM30 compared with control. Acetate proportion linearly increased, whereas propionate proportion linearly decreased with NALM supplementation. Blood urea nitrogen linearly decreased with NALM supplementation. Total plasma essential AA concentrations were quadratically affected, as greater values were observed for control and NALM45 than other treatments. Plasma Met concentration was quadratically affected as lower levels were observed with NALM15, whereas Met concentrations increased with NALM45 compared with control. Nitrogen utilization efficiency and apparent total-tract nutrient digestibility were not affected by treatment. Supplementation of NALM at 15 or 30 g/head per day resulted in the greatest improvements in feed efficiency without affecting N metabolism of early- to mid-lactation dairy cows.

Productive responses of dairy goats fed on diets containing elephant grass (Pennisetum purpureum) associated or not with cactus (Opuntia stricta) cladodes, and extra-fat whole corn germ as a substitute for corn

This study evaluated the effects of partial replacement of elephant grass (Pennisetum purpureum) with cactus cladodes (Opuntia stricta (Haw.) Haw.), and the replacement of corn with extra-fat whole corn germ (EFWCG) on the intake and digestibility of nutrients, and milk yield and composition of dairy goats. Twelve Saanen goats with an average body weight of 54 ± 2.0 kg and with 45 days in lactation were distributed into three simultaneous 4 × 4 Latin squares according to milk yield and assigned to four dietary treatments in a 2 × 2 factorial arrangement corresponding to two roughage sources (elephant grass associated or not with cactus cladodes) and two energy sources (corn or EFWCG, at 9.5 % of diet dry matter (DM)). The diets with cactus cladodes provided greater intake (P ≤ 0.01) of organic matter (OM), crude protein (CP), ether extract (EE), non-fibrous carbohydrates (NFC), greater digestibility (P ≤ 0.04) of dry matter and OM, shorter feeding and rumination times (P ≤ 0.0003), and lower urea nitrogen content in milk (P ≤ 0.003). Diets containing EFWCG provided a higher intake (P ≤ 0.004) of EE, lower intake of NFC, and higher concentration of fat and total solids in milk (P ≤ 0.04). Both diets without cactus cladodes and diets without EFWCG provided greater digestibility (P ≤ 0.003) of neutral detergent fiber (NDF). The diets with cactus cladodes and EFWCG showed higher intake (P ≤ 0.04) of DM, NDF, and metabolizable energy, and total and fat-corrected milk yields (P ≤ 0.03). The grass and EFWCG diets showed higher digestibility (P ≤ 0.03) of CP and EE. Partial replacement of elephant grass with cactus cladodes and inclusion of EFWCG as a substitute for corn increased DM intake and energy intake, which was associated with an improved productive performance of dairy goats. Therefore, this diet could be an interesting option for dairy goats in semiarid regions where cactus is an essential fodder for ruminant production.

Performance of lactating cows fed sugarcane silage treated with microbial additives

Background: No studies have been conducted evaluating sugarcane silage associated with both Lactobacillus plantarum and Pediococcus pentosaceus for lactating dairy cows. Objective: To evaluate diets containing different roughages with and without microbial inoculants on intake, digestibility and milk yield of medium-producing cows. Methods: A total of 15 Holstein cows distributed into a randomized block design were used. Dietary treatments were: 1) a corn silage-based diet (CS), 2) a fresh sugarcane-based diet (SC), 3) a sugarcane silage ensiled without inoculant (SS), 4) sugarcane silage ensiled with Lactobacillus buchneri (SSLB), and 5) sugarcane silage ensiled with Lactobacillus plantarum and Pediococcus pentosaceus (SSLP). Results: Digestible organic matter intake (DOMI) was lower (p&lt;0.05) in cows fed SSLB (9.77 kg day-1) when compared with cows fed CS (13.29 kg day-1) and SSLP (12.42 kg day-1). Ensiling of sugarcane increased intake of neutral detergent fiber (NDF) compared to SC (mean of 6.00 kg day-1 versus 4.97 kg day-1; p&lt;0.05). Dry matter digestibility was greater (p&lt;0.05) in CS (77.80%) compared with diets based on sugarcane silage, whereas NDF digestibility was lower for treatments with sugarcane (p&lt;0.05). Milk yield was similar among CS (27.99 kg), SC (25.59 kg), and silages with additives (25.47 and 27.07 for SSLB and SSLP, respectively). Cows fed CS produced more fat-corrected milk (25.89 kg) than those fed sugarcane-based diets (p&lt;0.05). Conclusions: Fresh sugarcane or sugarcane silage with additives can be used as a roughage source for dairy cows producing up to 23.43 kg d-1 fat-corrected milk, considering the total diet is properly balanced.

Impact of Dry Sugar Beet Pulp on Milk Production, Digestibility Traits, and Blood Constituents of Dairy Holstein Cows.

Simple SummaryThere are many agriculture by-products in the agriculture sector, and many of them have high socio-economic value. There is a growing interest in recycling agro-industrial by-products for feeding ruminants. Sugar beets are used to produce sugar and result in sugar beet pulp by-products, which can be used as feed for livestock, either as dried flakes or as compressed pellets. In this study, the effect of partial replacement of yellow corn grains (YCG) with dry sugar beet pulp (DSBP) at levels of 25 and 50% was evaluated with respect to the milk production and health condition of dairy Holstein cows. Partial replacement of YCG with DSBP in the rations of dairy cows led to significant improvements in the digestion, rumen activity, plasma biochemical parameters, milk yield, milk composition, feed use, and milk yield. Furthermore, the reduction in feed cost and the increase in milk yield improved with increasing DSBP in the ration. Thus, replacing feed ingredients with DSBP is recommended for feeding dairy Holstein cows with low-cost feeds without reducing their health status and production.Thirty multiparous lactating Holstein cows with an average live body weight of 642 ± 21 kg and an average daily milk yield of 30.46 ± 0.59 kg were used in this study. Cows with parities of 2 and 4 were used following their peak period, and were divided into three groups, with ten cows in each group. The control group was fed yellow corn grain rations (YCG), while for the 2nd and 3rd groups, 25 and 50% of YCG was replaced with dry sugar beet pulp (DSBP), denoted as DSBP25 and DSBP50, respectively. The contents of dry matter, organic matter, ether extract, nitrogen-free extract, and fiber carbohydrate in the experimental rations tended to decrease; however, crude protein, crude fiber, ash, and fiber fractions tended to increase in the DSBP25 and DSBP50 groups. Only crude fiber digestibility increased (p < 0.05) in the DSBP rations. Rumen pH value and concentration of ammonia nitrogen (NH3-N) decreased, while the concentration of total volatile fatty acids (TVFAs) increased in the DSBP25 and DSBP50 groups. The concentrations of total protein and globulin in blood plasma were higher (p < 0.05) in DSBP25 and DSBP50 than in YCG. However, plasma albumin concentration, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) activities were lower (p < 0.05) in DSBP50 than in YCG. Milk yield and yield of 4% fat-corrected milk (4% FCM) were higher (p < 0.05) in DSBP25 and DSBP50 than in YCG. Fat, protein, solids not fat (SNF), and total solids (TS) contents in milk increased significantly (p < 0.05) for feeding rations containing DSBP. Feed cost was reduced, but the output of milk yield increased with DSBP. In conclusion, introducing DSBP into the rations of Holstein dairy cows led to significant improvements in their productive performance.

Daytime Grazing in Mountainous Areas Increases Unsaturated Fatty Acids and Decreases Cortisol in the Milk of Holstein Dairy Cows.

Simple SummaryThe effects of grazing dairy cows in mountainous areas for 12 and 24 h compared with keeping the cows under confined settings were evaluated by examining the overall levels of fatty acids and cortisol in milk as an indicator of stress. Our findings revealed favorable changes in cows grazing for 12 h, with significantly improved milk fatty acid profile and decreased milk cortisol content. Additionally, we found no significant changes in the milk yield of 12 h grazed cows compared to the control group of confined cows, while milk fat and protein showed higher values in 12 h grazed cows. Grazing for 24 h caused a significant decrease in the milk yield compared to the two other groups. Overall, grazing for 12 h in a mountainous area is suggested to be beneficial for animal welfare, with positive improvements in milk fatty acids and lessening of stress levels without adverse effects on milk yield.The effects of grazing lactating cows in mountainous areas for 12 and 24 h compared with the confined indoor system were evaluated by examining the overall milk fatty acid and cortisol. Twenty-one dairy cows were allocated to three treatment groups: (1) control (confined management system in a free-stall barn; TMR based), (2) grazing for 12 h (12 hG; TMR plus grazing pasture), and (3) grazing for 24 h (24 hG; pasture-based feeding system). Dry matter intake was higher in the control and 12 hG groups than in the 24 hG group. The yields of total milk and the 3.5% fat-corrected milk were the lowest in the 24 hG group. Milk fat was the highest in the 24 hG group and higher in 12 hG compared with the control group. Milk protein and lactose levels were the highest in the 12 hG group. The highest somatic cell count was observed in the 24 hG group. The saturated fatty acid levels were higher in the control group compared with the 12 hG and 24 hG groups. There was no difference in overall mono-unsaturated fatty acids between 12 hG and 24 hG groups. Poly-unsaturated fatty acids were higher in the 12 hG group compared with the control and 24 hG groups. There was no difference in omega-6 (ω-6) fatty acids among the groups, and omega-3 fatty acids were higher in the 12 hG group than in the control group. Milk cortisol was the highest in the 24 hG group and higher in the control group compared with the 12 hG group. Taken together, grazing for 12 h is advisable for farms that have access to mountainous areas to improve the milk fatty acid profile and decrease the stress levels in high-yielding Holstein lactating cows.

Extruded urea-corn product can partially replace true protein sources in the diet for lactating Jersey cows

Non-protein nitrogen is a source of ammonia for rumen microorganisms to produce microbial protein, provided energy and required carbon skeletons are available. Extrusion of urea with corn plus Sulphur results in a slower ammonia release product (starea), which, associated with the energy source, would allow an increase in rumen microbial protein synthesis and could improve the efficiency of nitrogen utilization. Thus, the objective of this study was to evaluate the effect of replacement of true soybean meal protein by non-protein nitrogen source of extruded urea-corn-sulphur product (starea) on nutrient intake and apparent digestibility, lactation performance and blood parameters of lactating cows. Twenty Jersey cows in the middle third of lactation (initial milk yield = 11.98 ± 0.75 kg/day, and initial body weight = 409.10 ± 17.13 kg) were assigned according to milk yield to five treatments by randomized complete block design. The diet consisted of concentrate, corn silage and Tifton-grass. The concentrates were formulated so that the animals consumed 1.013 kg/day of crude protein from the concentrate, replacing soybean meal with starea at 0, 125, 250, 375 and 500 g/kg. Increasing starea in concentrate reduced daily dry matter intake (P = 0.003) without affecting milk yield and 4% fat-corrected milk yield. Total apparent digestibility of organic matter was improved by replacing soybean meal with starea (P = 0.022) and there was a tendency for improvement in dry matter digestibility. The components fat, protein, lactose and total milk solids were not changed by replacing soybean meal with starea. Milk urea nitrogen concentrations (P = 0.046) and plasma urea nitrogen before (P = 0.049) and after feeding (P = 0.001) increased linearly with the replacement of soybean meal by starea, but did not exceed the recommended levels. These results demonstrate that replacing soybean meal with starea can reduce dry matter intake, without altering TDN intake, because there was increasing linearly on organic matter digestibility, indicating starea effects in improving fiber degradation, without affecting milk production, milk components and blood parameters. Therefore, replacement of soybean meal with starea can be practiced up to 500 g/kg in concentrate for mid-lactation Jersey cow diets.

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.

Increasing doses of carbohydrases: Effects on rumen fermentation, nutrient digestibility, and performance of mid-lactation cows

The objective of this study was to evaluate the effects of exogenous enzymes on nutrient intake and digestibility, rumen fermentation, and productivity of mid-lactating cows. Experiment 1 was designed to test increasing doses [0, 0.5, 1.0, or 1.5 g/kg of dry matter (DM)] of a combination of 2 enzyme products with xylanase and β-glucanase activities (Ronozyme Wx and Ronozyme VP, respectively; DSM Nutritional Products) on rumen fermentation and total apparent digestibility. Enzyme combinations had a ratio of endo-1,3(4)-β-glucanase to endo-1,4-β-xylanase of 8:2 (wt/wt). For experiment 1, 8 rumen cannulated lactating cows were used into a double 4 × 4 Latin square design experiment with 14 d of diet adaptation and 7 d of sampling. Despite no differences in feed intake, carbohydrases linearly increased neutral detergent fiber digestibility. Treatments marginally affected rumen fermentation, where a linear trend for lower rumen pH and a linear trend for greater isobutyrate concentration were observed with increasing enzyme dose. A trend for lower rumen NH3-N concentration was observed for cows receiving carbohydrases in comparison with control group. When comparing all enzyme treatments against control group, cows fed enzymes tended to produce more 3.5% fat-corrected milk (FCM), produced more milk fat, and had greater blood glucose concentration. Experiment 2 evaluated 3 doses (0, 0.5, or 0.75 g/kg of DM) of the same combination of enzyme products on performance of cows (n = 36) in a complete randomized block (n = 12) design. Cows received treatments for 9 wk. No interaction effects between treatments and time were observed for all variables assessed in this study. In agreement with experiment 1, no differences were detected for feed intake, but cows fed the enzyme products tended to produce more 3.5% FCM and milk fat compared with control. In addition, cows fed enzymes exhibited greater efficiency of FCM production (FCM ÷ DM intake) compared with control. No differences were detected for intake and productivity when comparing the 2 doses of carbohydrases. In summary, the enzyme products tested in this study may improve feed efficiency due to greater milk fat concentration.