Pasture Neutral Detergent Fiber Research Articles

Comparison of milk and grass composition from grazing Irish dairy herds with and without milk fat depression

BackgroundThis study investigated the factors relating to pasture chemical and fatty acid (FA) composition that influence the milk fat percentage of spring calving, grazing dairy cows. The relationship between milk fat percentage and FA composition of the milk in these herds was also investigated.ResultsMilk protein percentage, milk casein percentage and cheddar cheese yield were increased in milk from HMF herds. Cows from LMF herds did not have negatively altered milk processability including rennet coagulation time (RCT), pH and ethanol stability. Crude protein, NDF, ADF, ether extract and total FA content of pasture was not different between LMF and HMF herds. Milk fat concentration of conjugated linoleic acid (CLA) t10, c12 was not different between HMF and LMF herds. Pre-grazing herbage mass and pasture content of crude protein, neutral detergent fibre (NDF) and total FA were similar between HMF and LMF herds. Pasture offered to LMF herds had a higher concentration of monounsaturated fatty acids (MUFA). A strong negative relationship (r = -0.40) was evident between milk fat percentage and pasture crude protein content for MMF herds (3.31–3.94% milk fat).ConclusionsThis research reports improved milk protein percentage, milk casein percentage and cheddar cheese yield from HMF herds compared to LMF herds. Milk processability was not impacted by low milk fat percentage. Pasture NDF and total fatty acid content was similar in HMF herds and LMF herds. Milk fat percentage had a strong negative association (r = -0.40) with pasture crude protein content in MMF herds (MF 3.31–3.94%). Correlation values between pasture chemical and FA composition and milk fat percentage in LMF herds and HMF herds were low, indicating that diet is not the only causative factor for variation in milk fat of grazing dairy cows. Comparison of milk fatty acid composition from herds with and without milk fat depression suggests that there may be other fatty acids apart from CLA t10, c12 that contribute to the inhibition of milk fat synthesis during milk fat depression in grazing herds.

Effects of Supplementation with Increasing Levels of Energy Concentrate on the Productive Response and Ruminal Digestion of Dairy Cows Grazing Lucerne Pasture

The aim of the study was to determine the effect of three levels of energy concentrate intake on dry matter (DM) and energy intake, milk yield and composition, rumen environment and pasture neutral detergent fiber (NDF) digestion. Twelve Holstein multiparous cows in early lactation (69.0 ± 5 days postpartum) producing 32.8 (±4.0) kg milk were assigned to three treatments at (kg/cow day) 3.5 (T3.5), 7.0 (T7.0) and 10.5 (T10.5) kg concentrate in a 3 × 3 Latin Square design. Parameters of ruminal environment and neutral detergent fiber (NDF) digestion were obtained using 3 additional rumen cannulated cows. Concentrate was composed (as fed) by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral premix including monensin and thoroughly consumed. Yields (kg/cow day-1) of milk, 4% fat corrected milk (4% FCM 4%) and energy corrected milk (ECM) resulted higher (p p -1 without effects on yield of milk fat. Concentrations (g/100 g) of milk fat (3.19), protein (2.97), total solids (11.75), non-fat solids (8.60) and casein (2.40) did not differ. Milk lactose content (g/100 g) was linearly increased (p p p p p < 0.05) in T3.5 due to the increase in acetate and butyrate while the acetate: Propionate ratio remained unchanged. Pasture NDF digestion was affected as concentrate intake increased. To increase milk protein yield and reduce concentrations of N-NH3 in rumen and milk, feeding an energy concentrate at 41% of total DM intake resulted an effective tool.

Milk Yield and Composition and Pasture Ruminal Digestion in Grazing Dairy Cows Receiving Three Levels of Energy Concentrate Supplementation

The objective of the experiment was to determine the effect of feeding three levels (T3.5, T7.0 and T10.5) of energy concentrate (3.5, 7.0 and 10.5 kg cow-1 day-1) on total dry matter (DM) and energy intakes, milk yield and composition, nutritional value of milk and rumen pasture neutral detergent fiber (NDF) digestion in grazing dairy cows. Twenty-one multiparous Holstein cows in early lactation (70.2 ± 13 days postpartum) producing 37.1 (±4.7) kg of milk were assigned to a 3 treatments (7 cows/treatment) × 3 periods Latin square design. Parameters of ruminal environment and pasture NDF degradation were obtained using 3 additional cows of the same breed fitted with rumen cannulae. On a wet basis, concentrate was composed by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral nucleus with monensin. Pasture (Medicago sativa, sp) was used in a rotational grazing system with an herbage allowance of 30 kg DM cow-1 d-1. Yield (kg cow-1 d-1) of fat corrected milk (4% FCM) resulted higher (p p p p p p p p

Substitution of ryegrass pasture with a high fibre concentrate supplement to grazing Jersey cows to overcome winter roughage shortages

The low growth rate of ryegrass pasture in the southern Cape area of South Africa during the winter months results in a gap in the fodder flow plan. The objective of this study was to determine whether roughage shortages during the winter months could be overcome by the substitution of pasture with a high fibre concentrate (HFC). This was determined by feeding varying levels of the HFC to cows grazing ryegrass pasture. Treatments were: Low concentrate (LC), where each cow received 4kg concentrate and 10kg dry matter (DM) pasture per day; medium concentrate (MC), where each cow received 7kg concentrate and 7kg DM pasture per day; high concentrate (HC), where each cow received 10kg concentrate and 5kg DM pasture per day. Forty eight lactating Jersey cows were blocked according to days in milk, lactation number and 4% fat corrected milk yield, to determine the effect of treatments on production. Cows within blocks were randomly allocated to one of three treatments. Eight ruminally cannulated Jersey cows were randomly allocated to the LC and HC treatments in a cross-over design, to determine the effect of treatments on rumen health. The metabolisable energy (ME), crude protein (CP) and neutral detergent fibre (NDF) contents of the HFC was 10.9MJ/kg, 145g/kg and 231g/kg, respectively. Cows in the three treatments grazed separately, allowing for the restriction of pasture intake according to treatments specifications. The ruminally cannulated cows grazed with the production study cows, in their respective treatments, throughout the study. The mean daily milk yield was higher for treatment HC (18.1kg/d) than for treatment LC (16.2kg/d), while treatment MC (17.3kg/d) remained intermediate. The mean milk fat content was lower for treatment HC (45.9g/kg) compared to treatment MC (49.6g/kg) and treatment LC (49.2g/kg). Rumen activity of cows in the HC treatment was inhibited. Rumen pH of cows in the HC treatment spent a longer time below pH 5.8 (7.43h) compared to cows in the LC treatment (6.24h). Pasture NDF degradation coefficient after 30h of incubation and rumen acetate concentration was higher for the LC treatment (0.42 and 75.11mM/L) than for the HC treatment (0.39 and 64.96mM/L). It was concluded that restricting pasture intake and feeding higher levels of a HFC is a viable option to overcome pasture shortages during winter months.

Milk production and &lt;i&gt;in sacco&lt;/i&gt; disappearance of pasture NDF in grazing Jersey cows receiving a barley based concentrate

The aim of the experiment was to determine the effect of feeding low (2.4 kg/d), medium (4.8 kg/d) and high (7.2 kg/d) levels of a barley-based concentrate on milk production and in sacco ruminal disappearance of dry matter (DM) and neutral detergent fibre (NDF) in Jersey cows grazing a Westerwold ryegrass pasture. Sixty Jersey cows in early- to mid lactation were randomly allocated to one of three treatments (n = 20). Milk production tended to increase when concentrate level was increased from 2.4 to 4.8 kg/day. Fat corrected milk yield, milk fat yield and milk fat percentage were not affected by treatment. Protein yield only increased when the concentrate level was increased from 2.4 to 4.8 kg/cow per day but there was no further increase when feeding the high level of concentrate. Live weight change and body condition score only increased when the concentrate was fed at 7.2 kg/cow per day. An additional 12 Jersey cows, fitted with ruminal cannulae, were randomly allocated to the High and Low concentrate treatments in a two-period crossover design. Rumen liquid samples were collected every four hours for the determination of rumen pH and volatile fatty acid (VFA) concentrations. Rumen pH was not affected by treatment while total VFA, acetate and isovalerate concentrations increased when the level of concentrate mixture was increased. Rumen NH3-N concentrations were not affected by treatment. The in situ nylon bag technique was used to determine DM and NDF degradation of the pasture. Pasture samples were incubated in the rumen for 0, 4, 8, 12, 20, 30, 48, 72 and 96 hours. Increasing the concentrate mixture did not affect in situ disappearance of pasture DM and NDF, or the rate of degradation. It was concluded that the supplementation of a barley based concentrate to pasture based Jersey cows does not improve animal response when fed at levels higher than 4.8 kg/cow per day. South African Journal of Animal Science Vol. 37 (2) 2007: pp. 81-89

Assessment of forage biomass and quality parameters of bermudagrass using proximal sensing of pasture canopy reflectance

AbstractAssessments of forage productivity and quality during the growing season can help livestock managers make decisions for adjusting stocking rate and managing pastures. Traditional laboratory methods of forage quality determination are usually time consuming and costly. Remote sensing may provide a rapid and inexpensive means of estimating forage biomass and quality variables. Canopy reflectance measurements were made, using a spectroradiometer, in five warm season grass pastures during the 2002 and 2003 growing seasons to develop and validate algorithms to predict above‐ground biomass, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) concentrations and CP availability (i.e. CP concentration × biomass yield) of the pastures. Forage biomass correlated (r2 = 0.36, P &lt; 0.0001) with a ratio of reflectance at 1145 and 1205 nm wavebands (R1145/R1205). Crude protein concentration and CP availability correlated linearly with R1695/R605 and R875/R735 (r2 = 0.61 and 0.47, P &lt; 0.0001), respectively. Although NDF and ADF correlated significantly (P &lt; 0.0001) with the reflectance ratios, the best reflectance ratios only explained 13–35% of ADF and NDF variations. Multiple regression (MAXR) models with a total of 10‐waveband entrances improved the relationships between forage quality and canopy reflectance values (r2 = 0.27 − 0.74, P &lt; 0.0001). Validation of developed equations indicated that forage biomass, CP concentration, and CP availability could be predicted using either the reflectances at 10 wavebands or the two‐band reflectance ratios. Pasture NDF could also be predicted using the 10‐band MAXR equation (r2 = 0.58). Our results suggest that biomass and major quality parameters of warm season grass pastures can be rapidly and nondestructively predicted using canopy reflectance data.

Development of Canopy Reflectance Algorithms for Real‐Time Prediction of Bermudagrass Pasture Biomass and Nutritive Values

Timely assessments of forage biomass production and nutritive values during the growing season are important for livestock managers to make decisions for adjusting stocking rate and pasture management. Remote sensing of canopy reflectance may provide a rapid and inexpensive means of estimating pasture nutritive values and biomass. The objective of this study was to determine the relationships between neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP) concentration, biomass, and CP availability of bermudagrass [Cynodon dactylon (L.) Pers.] pastures and canopy reflectance. An experiment was conducted in the 2002 and 2003 growing seasons using three bermudagrass pastures of ‘Midland’, ‘Ozarka’, and an experimental hybrid, 72x12–12. Pasture CP concentration, biomass and CP availability correlated linearly with the reflectance ratios of R605/R515, R915/R975, and R875/R725 (0.44 ≤ r2 ≤ 0.63) as well as with the first derivatives of reflectance with wavebands centered at 545, 935, and 755 nm (0.49 ≤ r2 ≤ 0.68). Linear equations between each forage variable and the ratios or derivatives of reflectance were developed on the basis of data pooled across years, plant genotypes, and sampling dates. Validation of developed equations indicated that the CP concentration, biomass, and CP availability could be predicted by either the ratios or derivatives of the reflectance. Pasture NDF and ADF had lower correlation with canopy reflectance than other measured variables. Our results suggest that two‐narrow‐waveband reflectance ratios or the first derivatives in visible and near‐infrared spectral regions can be used for real‐time and nondestructive prediction of forage productivity and CP content in bermudagrass pastures.

Calves Weaned and Backgrounded on Pasture Respond to Pasture Nutritive Value and Supplements

Preconditioning reduces stress, maintains health, and adds value to feeder calves. Calf response to pasture nutritive value and supplementation was studied on 17 farms in 2002, 8 farms in 2003, and 9 farms in 2004. Calves were weaned in late August and backgrounded on pasture to mid-October. Calves were fed a commercial concentrate (0.0 to 1.5% bodyweight [BW]), hay, and on some farms haylage, ground shelled corn (Zea mays L.), or soybean (Glycine max L.) hulls. Calf average daily gain (ADG) was evaluated across farms relative to animal, pasture, and supplement characteristics using multiple regressions. Commercial supplement intake, corn intake, and pasture total digestible nutrient (TDN) or pasture neutral detergent fiber (NDF) significantly influenced calf ADG. Based on regression coefficients, 4.4 lb of commercial supplement or 4.1 lb of corn were required to produce 1 lb of additional gain. Increasing pasture TDN or decreasing pasture NDF by 10 percentage units increased ADG 0.86 or 0.48 lb/day, respectively. Regressions were tested against 2004 data. Regression-estimated gains were not significantly different from measured ADG 67% of the time. Calf performance during backgrounding can be cost effective when management ensures adequate pasture quantity and nutritive value and supplements are used judiciously relative to their cost and the value of calf gain.

Effects of spring grazing on dryland perennial ryegrass/white clover dairy pastures. 1. Pasture accumulation rates, dry matter consumed yield, and nutritive characteristics

A 3-year experiment (September 1999–August 2002) was conducted in south-western Victoria to determine the impact of spring grazing on pasture accumulation rates, dry matter (DM) consumed yield (estimate of DM yield), and pasture nutritive characteristics [metabolisable energy (ME), crude protein (CP), neutral detergent fibre (NDF), and water-soluble carbohydrates (WSC)] of a perennial ryegrass (Lolium perenne L.)–white clover (Trifolium repens L.) pasture. Spring grazing treatments, applied annually from September to November, were based on ryegrass leaf development stage with high (HF), medium (MF), and low (LF) grazing frequency being 2-, 3-, and 4-leaf stage, respectively, and post-grazing height as the grazing intensity with high (HI), medium (MI), and low (LI) grazing intensity being 3, 5, and 8 cm, respectively. Five combinations were used: HFHI, LFHI, MFMI, HFLI, and LFLI. A sixth treatment, rapid grazing (RG), maintained pasture between 1500 and 1800 kg DM/ha by grazing weekly during spring, and a seventh and eighth treatment, simulating forage conservation for early-cut silage (lock-up for 6–7 weeks; SIL) and late-cut hay (lock-up for 11–12 weeks; HAY), were also included. For the remainder of the year, all plots were grazed at the perennial ryegrass 3-leaf stage of growth, or when pasture mass had reached 2800 kg DM/ha, and grazed to a residual height of 5 cm. On average, pasture accumulation rates ranged from &lt;5 (February–March) to 100–110 kg DM/ha.day (September–October). Overall, SIL resulted in a lower accumulation rate than all other treatments. High spring grazing frequency (including RG) treatments led to more grazing events than medium and low spring grazing frequency treatments. In Years 1, 2, and 3, DM consumed ranged from 9.7 (HAY) to 16.3 (RG), 4.2 (HAY) to 10.1 (HFHI), and 7.3 (SIL) to 10.9 t DM/ha.year (HAY), respectively. HAY resulted in a lower pasture ME content than SIL, HFHI, and LFHI spring grazing, and LFLI spring grazing resulted in a lower pasture ME content than all other treatments except HAY. HFHI grazing resulted in an increase in ME content over time, whereas the rate of increase in ME content over time was higher for LFLI spring grazing than for HAY, RG, and HFLI spring grazing. For all treatments, average pasture ME content ranged from 9.4 (January–February) to 11.4 MJ/kg DM (September). HAY resulted in a lower CP content than all treatments except LFLI grazing. RG resulted in no change in CP content over time. For all treatments, average pasture CP content ranged from a low of 11–14 (January–February) to a high of 24–28% DM (August–September). LFLI grazing resulted in a higher NDF content than HFHI, LFHI, MFMI, and HFLI grazing, while RG resulted in a lower NDF content than LFHI, MFMI, and HFLI. For all treatments, average pasture NDF content ranged from a low of 48–55 (August–September) to a high of 58–62% DM (January–February). All treatments resulted in an increase in pasture WSC content over time. The results demonstrate that frequent and intense grazing management (e.g. HFHI and RG) during spring is important in maintaining high pasture DM yields. Results also indicate positive pasture nutritive characteristic (ME, CP, and NDF) gains with more frequent spring grazing than with infrequent spring grazing. No treatment effect was observed for WSC content.

Factors Affecting Pasture Intake and Total Dry Matter Intake in Grazing Dairy Cows

We investigated the most relevant variables for estimating pasture intake and total dry matter (DM) intake in grazing dairy cows using 27 previously published studies. Variables compared were pasture allowance, days in milk, amount of forage, amount of concentrate and total supplementation, pasture allowance and supplementation interaction, fat-corrected milk, body weight (BW), metabolic BW, daily change in BW, percentage of legumes in pasture, neutral detergent fiber (NDF) contents of pasture, and NDF in pasture selected. The variables were selected using stepwise regression analysis for total DM intake and pasture DM intake. Variables selected in the total DM intake regression equation (R2 = 0.95) were pasture allowance, total supplementation, interaction of pasture allowance and supplementation, fat-corrected milk, BW, daily change in BW, percentage of legumes and pasture NDF content. Pasture DM intake regression equation (R2 = 0.90) was similar to total DM intake equation, but supplementation coefficient was negative, showing substitution effect in supplementing grazing cows.The intake of NDF as a percentage of BW was higher than 1.3% when considering NDF content of the pasture allowance. Low pasture allowance groups had values higher than 1.3%.

Effect of rate and time of nitrogen application from autumn to midwinter on perennial ryegrass - white clover dairy pastures in western Victoria. 2. Pasture nutritive value

Field experiments were carried out at 2 sites to study the effects of time and rate of nitrogen (N) application from autumn to midwinter on the nutritive value of perennial ryegrass–white clover dairy pastures in western Victoria. Nitrogen (0, 15, 25, 30, 45, and 60 kg/ha) was applied in mid-April, early May, mid-May, early June, and mid-June during 1996 onto a pasture which had been grazed and topped to a uniform height of 5 cm prior to imposition of treatments. Pasture samples to a height of 5 cm were collected when perennial ryegrass in the 45 kg N/ha treatment reached the 3-leaf stage of development. Samples were analysed for metabolisable energy (ME), crude protein (CP), neutral detergent fibre (NDF), and water-soluble carbohydrates (WSC). Increasing rates of N gave rise to a curvilinear (Site 1) and linear (Site 2) increase in pasture ME and CP content. The actual response of 0.007 MJ/kg DM. kg N at 45 kg N/ha was the same at both sites, regardless of N application time, and corresponded to an increase of 0.32 MJ/kg DM. At Site 1 the actual increase in CP content at 45 kg N/ha (0.067% per kg N applied) was the same for all application times and corresponded to an increase in CP content of 3%. For Site 2, the increase ranged from 0.040% (mid-April) to 0.098% (mid-May) per kg N, corresponding to a pasture CP content increase of 1.8 to 4.4% at 45 kg N/ha, respectively. The application of N gave rise to a curvilinear (Site 1) and linear (Site 2) decrease in pasture NDF. For Site 1 at 45 kg N/ha, the actual decrease ranged from –0.04% (early May) to –0.10% (mid-May) per kg N, corresponding to a pasture NDF content decrease of 1.69 to 4.61%, respectively. At Site 2, the actual decrease in NDF content (–0.04% per kg N applied) was the same for all application times and corresponded to a decrease of 1.58% at 45 kg N/ha. Apart from some exceptions, increasing rates of applied N gave rise to a linear (Sites 1 and 2) decrease in pasture WSC content. For Site 1, the change in pasture WSC content ranged from 0.007% (early May) to –0.032% (mid-June application) per kg N, corresponding to a change in pasture WSC content of 0.32 to –1.44% at 45 kg N/ha, respectively. At Site 2, the change in WSC content ranged from 0.0004% (mid-April) to –0.076% (mid-May) per kg N, corresponding to a change in pasture WSC content of 0.02 to –3.42% at 45 kg N/ha, respectively. In this study, N application had a positive effect on the nutritive value of dairy pastures in the autumn to midwinter, in western Victoria. This is particularly important for the provision of quality feed during this period as the majority of dairy herds in the region are calving at this time. Thus, the provision of an increased quantity of higher quality feed may lead to a reduction in the requirement for purchased feeds.

Spring and autumn nitrogen fertiliser effects, with and without phosphorus, potassium and sulphur, on dairy pastures: Pasture nutritive value and mineral content

Experiments were conducted at three sites to examine effects of applying different nitrogen (N) fertilisers at 45 kg N ha−1, with and without phosphorus (P), potassium (K) and sulphur (S) on dairy pasture nutritive value and mineral content in autumn and spring. Pasture nutritive value was assessed by measures of crude protein (CP), metabolisable energy (ME), water‐soluble carbohydrates (WSC) and neutral detergent fibre (NDF). Pasture mineral content was assessed by estimates of the major minerals phosphorus (P), potassium (K), sulphur (S), sodium (Na), calcium (Ca), and magnesium (Mg), and trace minerals manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn). Apart from some exceptions, applications of N, with and without additional P, K and S generally increased pasture CP and ME content in autumn and CP content in spring. Again with some exceptions, pasture WSC content was unaffected by fertiliser application in autumn, but was decreased by some treatments (containing N and N with P, K and S) in spring. Fertiliser treatments generally had no effect on pasture NDF content at Sites 1 and 3 during autumn and spring. At Site 2, some treatments (containing N and N with P, K and S) reduced pasture NDF content in autumn while during spring some treatments (containing N and N with P, K and S) increased pasture NDF content. Different N fertilisers applied at the same rate, with and without additional P, K and S, generally produced the same effect on pasture nutritive value. The application of P, K and S in the absence of N generally had no effect on pasture nutritive value. Apart from some exceptions, pasture P content was increased by fertiliser treatments including P, K and S, but N on its own did not influence pasture P content. Pasture K content was generally not influenced by treatment. At Site 1 during autumn and spring, and at Site 3 during spring, treatments containing P, K and S increased pasture S content while applications of N had no effect. At Site 2 during autumn, P, K and S increased pasture S content relative N only, while during spring pasture S content was generally increased by all treatments. At Site 3 during autumn, applications of N decreased pasture S content while P, K and S increased pasture S content relative to no fertiliser. Pasture Na and Ca content were generally not influenced by treatment. Pasture Mg content was not influenced by treatment at Sites 2 and 3. At Site 1 during autumn and spring, however, some treatments (containing N and N with P, K and S) increased pasture Mg content. Fertiliser treatments produced no consistent patterns or differences with respect to trace minerals (Mn, Fe, Cu and Zn).