Effect Of Silage Research Articles

Effect of silages on concrete and process of its corrosion in the course of time

Abstract Silages are important juicy bulky feedstuff, that has irreplaceable role in nutrition of farm animals – cattle, pigs and horses. The silages are made of a fresh plant mass (e.g. corn, alfalfa, rape, clover or grass), that is in a chopped form in an exactly given way ensiled, i.e. in a tamped or pressed form without access of air subjected to a fermentation process. Within this process acid juices are created and enter into a construction of containers aimed for the ensilage process. These containers are mainly from a reinforced concrete. Influence of the silage on the concrete is a difficult process and it depends on several factors. From the point of view of durability/resistance to the silage effect, a concrete composition is a significant factor, the other factors are silage properties as well as time of a contact of the concrete with the silage. In this paper we describe findings on a state of 3 concrete compositions, which were repeatedly subjected to a corn silage for 3 years. In a 1-year interval, an effect of the silages on physico-mechanical properties of the concrete (e.g. strength, absorptivity, porosity) was observed. The highest resistance to effect of the silages in the course of time was proven for the concrete with a higher content of Portland cement.

Effect of carbohydrate type in silages and concentrates on feed intake, enteric methane, and milk yield from dairy cows

Dietary carbohydrate manipulation can be used to reduce enteric CH4 emission, but there is a lack of studies on the interaction of different types of carbohydrates that can affect feed intake and ruminal fermentation. Understanding this interaction is necessary to make the most out of CH4 mitigation feeding strategies using different dietary carbohydrates. The aim of this study was to test the effect on enteric CH4 emission, feed intake and milk production response when cows were fed either grass-clover (GCS) or corn silage (CS) as the sole forage source (55% of dry matter, DM), in combination with either barley (BAR) or dried beet pulp (DBP) as a concentrate (21.5% of DM). Twenty-four (half first and half second parity) cows were used in a crossover design with 2 periods of 21 d each, receiving 2 of 4 diets obtained from a 2 × 2 factorial arrangement of the experimental diet. Feed intake, CH4 emission metrics and milk production were recorded at the end of the experimental periods. The diets had NDF concentrations between 258 and 340 g/kg of DM, and starch concentrations between 340 and 7.45 g/kg of DM (CS-BAR and GCS-DBP, respectively). The effects of silage and concentrate on dry matter intake (DMI) were additive, with the highest feed intake in cows fed COR-BAR, followed by cows fed COR-DBP, GCS-BAR, and GCS-DBP (21.2, 19.9, 19.1, and 18.3 kg/d). Energy corrected milk (ECM) yield was not affected by silage source in first parity cows, but it was higher for cows fed CS than cows fed GCS in second parity. The effects of silage and concentrate on CH4 production (g/d), yield (g/kg of DMI) and intensity (g/kg of ECM) were not additive as cows fed GCS had similar responses regardless of the concentrate used, but cows fed CS had lower CH4 production, yield and intensity, when fed BAR instead of DBP. The lower CH4 production, yield and intensity in cows fed CS-BAR compared with other diets could be partially explained by the nonlinear relationship between ruminal VFA and carbohydrates (NDF and starch) concentration reported in literature, however, we observed a linear relationship between acetate:propionate ratio and CH4 yield, suggesting possible other effects. The effects of silage and concentrate on the ruminal VFA were additive in first parity cows, but not in second parity cows. The interaction between dietary CHO type and parity might indicate an effect of feed intake or the energy balance of the cow. Feeding cows silage and concentrate both rich in starch can result in the lowest enteric CH4 emission.

Dwarf and tall elephant grass silages: intake, nutrient digestibility, nitrogen balance, ruminal fermentation, and ingestive behavior in sheep.

The objective of this study was to evaluate the exclusive supply of dwarf or tall elephant grass silages, harvested at 60days of growth, without wilting or the use of additives, on intake, apparent digestibility, nitrogen balance, rumen parameters, and ingestive behavior of sheep. Eight castrated male crossbred sheep (57.6 ± 5.25kg body weight), fistulated in the rumen, were distributed in two 4 × 4 Latin squares with four treatments and eight animals per treatment and four periods. The treatments consisted of four elephant grass genotype silages (Mott, Taiwan A-146 2.37, IRI-381, or Elephant B). There was no effect of silages (P > 0.05) on dry matter, neutral detergent fiber, and total digestible nutrient intake. The dwarf-sized elephant grass silages provided higher crude protein intake (P = 0.047) and N intake (P = 0.047), while the IRI-381 genotype silage provided higher non-fibrous carbohydrate intake compared to Mott (P = 0.042), without differing from Taiwan A-146 2.37 and Elephant B silages. There were no differences (P > 0.05) among the digestibility coefficients of the evaluated silages. It was observed that silages produced with Mott and IRI-381 genotypes caused a slight decrease in ruminal pH (P = 0.013), and the propionic acid concentration was higher in the rumen fluid of the animals fed with Mott silage (P = 0.021). Therefore, dwarf or tall elephant grass silages, produced with cut genotypes at 60days of growth and without the use of additives or wilting process, can be used in sheep feeding.

Enhanced silage pretreatment improving the biochemical methane potential of Miscanthus sinensis.

The choice of silage additives is an important factor for the storage of silage. One standard ensiling method and two enhanced ensiling methods (using natural silage, silage with mixed lactic acid bacteria, and silage with acetic acid, respectively) were carried out on Miscanthus sinensis. To determine the effects of these different methods, the biochemical methane potential (BMP) was determined. The results revealed that ensiling with acetic acid was the best method among the three ensiling methods. Acetic acid could quickly reduce the pH of the system to inhibit the growth of harmful bacteria. The rate of loss of dry matter was 0.92% when acetic acid was added, and the cumulative methane production was 149.6mL·g-1 volatile solids. From an analysis of correlations between the properties and BMP of silage, the contents of acetic acid and total volatile fatty acids were significantly correlated with the BMP. This study provides a theoretical basis for improving the BMP of M. sinensis and achieving better effects of silage.

High-digestible silages allow low concentrate supply without affecting milk production or methane emissions

In this study, we tested a response function comprising responses in milk to changes in organic matter digestibility of silages and concentrate supply. We studied the effect of changes in silage digestibility and concentrate supply on milk yield, feed intake, body weight, and methane production using 60 Norwegian Red cows. The experiment was a complete randomized block design comprising 3 periods. The pre-experimental period lasted 20 d and all the cows were fed a common silage for ad libitum intake and concentrate according to yield. Next, response period 1 lasted 17 d and the cows were divided into 2 treatments, where a low-digestible silage (LDS) was fed to half of the cows, and the other half were fed a high-digestible silage (HDS). Both groups were fed silage for ad libitum silage intake. Concentrate was optimized according to the yield and type of silage offered. In this period, the effect of silage was evaluated using a mixed model, including the results from pre-experimental period, with parity as a covariate and animal as a random effect. In response period 2, which lasted 20 d, the concentrate level was evaluated by dividing the silage digestibility treatments further into 3 subgroups. Concentrate was increased by 2 kg of dry matter (DM) per day, decreased by 2 kg of DM/d, or remained unchanged. In response period 1, silage treatments were optimized to obtain similar yields and resulted in a lower concentrate offer to HDS treatment. However, the HDS treatment showed a 3.0 kg of DM/d higher total feed intake due to a higher than expected silage intake. This resulted in 3.5 kg higher energy-corrected milk (ECM). Methane emissions were similar between silage treatments, but HDS showed lower methane per kilogram of DM due to its higher intake. The effect of concentrate supply level and interaction with silage digestibility was evaluated using mixed models, including the results for response period 1, with parity as a covariate and animal as a random effect. The reduction in concentrate offer by 2 kg/d in response period 2 was compensated for by increased 1.3 kg of DM/d of silage intake for HDS, resulting in similar intake (22.1 kg of DM/d and 21.7 kg of DM/d without and with concentrate reduction, respectively) and ECM yields (29.4 and 29 kg of ECM without and with concentrate reduction, respectively). However, concentrate offer reduction could not be compensated for by increased silage intake for LDS and resulted in lower milk yields (27.5 kg of ECM). Increased concentrate showed a higher marginal ECM response (kg of ECM per kg of additional concentrate intake) for LDS (1.8 vs. 3.3 kg of ECM for HDS and LDS, respectively). Thus, the drop in milk yields could be compensated for by increased concentrate offers if LDS are fed. Total methane production increased with increased concentrate intake, regardless of silage digestibility. Methane emissions per unit of milk were affected by total DM intake rather than by changes in silage digestibility and concentrate level. The results of this study are based on short-term periods and could show differences if study periods were longer; the results should be interpreted accordingly.

Technological properties of cow milk with the addition in their diet of silage prepared with bio-preservative “GreenGrass 3×3”

The completeness of the provision of the body of highly productive cows with the necessary set of nutrients depends on the set of feeds included in their diet, as well as on their quality. The purpose of the research is to study the effect of silage with the biological preservative “GreenGrass 3×3” on the technological properties of milk from cows of Holstein and Ayrshire breeds. It is found that the morphological and biochemical composition of the blood in the animals of the experimental groups significantly improves approaching the optimal parameters. Feeding lactating cows with silage in feed mixture from lucerne prepared with bio-preservative increases the average daily milk yield by 20.5% in the Holstein breed and by 26.9% in the Ayrshire breed. The quality of milk is improved by the increase in the mass fat fraction by 0.10-0.13% respectively, the mass protein fraction - by 0.10-0.14%, including casein - by 0.14-0.19%. In the general structure of milk proteins, the mass fraction of casein increases, while the mass fraction of whey proteins, on the contrary, decreased by 2.0-2.2%. It is very important that the proportion of γ-caseins, which do not clot under the influence of rennet, decreased by 0.5-0.9% in the test samples. As a result, the duration of clotting by rennet decreased by 13.8-12.1% and the loss of dry matter with whey - by 1.3-2.1%, the yield of casein clot increased by 5-4% and its density increased by 0,37-0.22 g / cm2. All these aspects show the increase in the technological properties of milk in cows from the experimental groups.

Changes in the fatty acid composition of steer subcutaneous fat, including biohydrogenation products, are minimal when finished on combinations of corn and barley grains and silages

Corn production in Western Canada has increased with development of short-season varieties partially offsetting the use of barley as a silage and grain source. The current study evaluated effects of silage and cereal-grain source on subcutaneous fat (SCF) composition of finishing cattle. Steers (465 ± 28.0 kg) were assigned to 24 pens (12 steers per pen) in a 2 × 3 factorial design for an 89 d finishing study. Diets contained corn silage or barley silage at 8% [dry matter (DM)] combined either dry-rolled barley grain (BG; 86% of DM), corn grain (CG; 85% of DM), or an equal blend of BG and CG (85% of DM). Bone-in ribeyes were collected from four steers per pen, and subcutaneous fatty acids were analyzed by gas chromatography. Feeding dry-rolled CG increased dietary fat and 18:2n-6 concentrations, resulting in small increases in 18:2n-6, total n-6 fatty acids, and n-6/n-3 ratios in SCF (P < 0.05). There were no changes in proportions of major trans-18:1 isomers (t10-18:1 or t11-18:1), the main natural isomer of conjugated linoleic acid (cis9,t11–18:2), or n-3 fatty acids. Substitution of dry-rolled CG for BG in finisher diets can, therefore, be done without substantially altering the fatty acid composition of beef fat, including polyunsaturated fatty acid biohydrogenation products.

Effect of silage and soybean straw based Total Mixed Ration (TMR) on the growth performances of growing bull calves

This study was undertaken to know the effect of silage and soybean straw based Total Mixed Ration (TMR) on the growth performances of growing bull calves. 30 growing bull calves were divided into 5 treatment groups considering their initial body weight 111.30±6.67 to115.66±10.69 kg and age 24 to 26 months, respectively. Five types of TMR were prepared with different roughage and concentrate ratios (R: C) as T1=70:30, T2=60:40, T3=50:50, T4=40:60, T5=30:70. TMR intake, DM intake, CP intake of animals in T2 group was significantly (P<0.001) higher. Significantly higher (P<0.01) DM and CP digestibility were observed in T2. No significant differences observed for live weight gain. The ADG was slightly higher in T2 group (0.860 kg/day) but no significant differences were found among the treatments. Based on the results, it may be concluded that using a 60:40 (R: C) TMR can be formulated for fattening bulls for proper growth and maintenance.
 Bangladesh J. of Livestock Res. 21-25: 82-88, 2018

ГЕМАТОЛОГИЧЕСКИЕ И БИОХИМИЧЕСКИЕ ПОКАЗАТЕЛИ ПРИ СКАРМЛИВАНИИ БЫЧКАМ СЕНАЖА, КОНСЕРВИРОВАННОГО СИЛОСТАНОМ И ЛАКСИЛОМ

The purpose of this research is to increase the meat productivity of bull-calves of black-motley breed at the expense of introduction in a diet of silage, canned luxilon and Cilostazol. Hematological, biochemical and other indicators are significantly influenced not only by the physiological state of the patient (age, pregnancy, productivity), but also by the conditions of feeding, maintenance, exploitation, and habitat. However, the picture of the blood retains its individual and specific features. Blood is one of the liquid media of the body, through which the bodies, tissues and cells are replenished with the necessary substances for life (vitamins, macro - and microelements, etc.), as well as the excretion of metabolic products. Changes in the morphological and biochemical composition of the blood – an indicator of the developing latent stages of the body's disease due to metabolic disorders. The article presents the results of studies on the effect of silage from alfalfa harvested preservatives elastan and laxil on hematological parameters of blood of calves of black-motley breed. It is established that hematological parameters of bull blood throughout the period of scientific and economic experience in all groups of experimental animals were within physiological norm and in its borders changed accordingly with metabolism in an organism and intensity of growth of animals. The content of red blood cells increases by 6.2 and 7.3%, hemoglobin-by 4.3 and 6.2%, total protein-by 2.8 and 5.7%, calcium – by 10.3 and 14.9%, phosphorus-by 3.1 and 4.9%. Overall hematological parameters in the course of the experiment in all groups of experimental calves were within the physiological norm, and its boundaries have been changed accordingly with the metabolism in the body and intensity of growth of animals.

Carcass characteristics of lambs fed diets containing silage of different genotypes of sorghum

Thirty-five feedlot lambs (without defined breed, aged between 5 and 7 months, with average live weight of 17.7±3.7 kg) were used in a completely randomized design to evaluate the effect of diets containing different genotypes of sorghum on morphometric measurements and qualitative characteristics of carcass and yields of primal cuts. The animals stayed in individual indoor pens for 42 days and slaughtered at an average weight of 26.24 kg. No significant differences were observed on morphometric measurements, hot (11.67 kg) and cold (11.39 kg) carcass weight, hot (44.46%) and cold (43.37%) carcass yields, biological yield and on cooling losses. There was also no significant effect of silages of different genotypes of sorghum on the weights and yields of retail cuts (neck, shoulder, rib, loin and leg) and on the subjective evaluation of carcasses. It is possible to finish sheep without defined breed feeding them diets based on silages of sorghum, resulting in carcasses with high yield and good conformation.

Effects of silage from maize crops differing in maturity at harvest, grass silage feed value and concentrate feed level on performance of finishing lambs

The effects of (i) medium and high feed value (MFV and HFV) maize silages and (ii) MFV and HFV grass silages, each in combination with a range of concentrate feed levels, on the performance of finishing lambs were evaluated using 280 Suffolk-X lambs (initial live weight 36.1 kg). The MFV and HFV maize silages represented crops with dry matter (DM) concentrations of 185 and 250 g/kg, respectively, at harvest, and had starch and metabolisable energy (ME) concentrations of 33 and 277 g/kg DM and 9.6 and 11.0 MJ/kg, respectively. HFV and MFV grass silages had DM and ME concentrations of 216 and 294 g/kg and 11.0 and 11.5 MJ/kg DM, respectively. A total of 13 treatments were involved. The four silages were offered ad libitum with daily concentrate supplements of 0.2, 0.5 or 0.8 kg per lamb. A final treatment consisted of concentrate offered ad libitum with 0.5 kg of the HFV grass silage daily. Increasing the feed value of grass silage increased (P < 0.001) forage intake, daily carcass and live weight gains, final live weight and carcass weight. Increasing maize silage feed value tended to increase (P = 0.07) daily carcass gain. Increasing concentrate feed level increased total food and ME intakes, and live weight and carcass gains. There was a significant interaction between silage feed value and the response to concentrate feed level. Relative to the HFV grass silage, the positive linear response to increasing concentrate feed level was greater with lambs offered the MFV grass silage for daily live weight gain (P < 0.001), daily carcass gain (P < 0.01) and final carcass weight (P < 0.01). Relative to the HFV maize silage, there was a greater response to increasing concentrate feed level from lambs offered the MFV maize silage in terms of daily carcass gain (P < 0.05) and daily live weight gain (P = 0.06). Forage type had no significant effect on the response to increased concentrate feed level. Relative to the MFV grass silage supplemented with 0.2 kg concentrate, the potential concentrate-sparing effect of the HFV grass silage, and the MFV and HFV maize silages was 0.41, 0.09 and 0.25 kg daily per lamb, respectively. It is concluded that increasing forage feed value increased forage intake and animal performance, and maize silage can replace MFV grass silage in the diet of finishing lambs as performance was equal to or better (depending on maturity of maize at harvest) than that for MFV grass silage.

Effect of Silage from Maize and Strip-Cropped Sorghum and Maize on Dairy Cow's Yield and Milk Composition

Effect of Silage from Maize and Strip-Cropped Sorghum and Maize on Dairy Cow's Yield and Milk CompositionIn an experiment conducted on 34 mid-lactation dairy cows of the Red-and-White and Black-and-White breed, in a random square design, the effect of maize or sorghum-maize silage present in partly mixed ration (PMR) on milk yield, milk composition and blood serum parameters was investigated. The PMR diet contained maize silage, which compared with PMR diet contained sorghum-maize silage made from strip-cropped plants. Both fodder plants were harvested with a 4-row precision chopper, which cut 2 rows of maize and 2 rows of sorghum, giving mixed maize/sorghum forage. The feeding experiment lasted 84 days and consisted of four sub-periods, each 21 days in length to record milk yield, feed and milk chemical composition, and blood parameters. In addition to PMR diets containing part of ration compound feedingstuffs, the cows received part of compound feedingstuffs given at feed stations to meet their nutritional requirement. The compound feedingstuffs in station were controlled by an electronic system related to actual cow's milk yield. Chemical composition of both silages and milk production efficiency were compared. The average dry matter intake in both groups was 18.80 vs 20.4±1.95 kg/day, but compound feedingstuff intake from station was 3.61 vs 4.56 (P&gt;0.01). Milk yield was 21.8 and 20.5±0.51 kg/day, respectively (P&gt;0.01). The amount of standardized fat and protein content of milk (FPCM) was 21.0 and 20.2 kg/g ±0.48 kg/day (P≥0.01). No significant differences were found in the fat, protein, casein, lactose, urea, total solids and solids not fat percentage of milk or in milk traits (acidity, renneting time, density) among groups (P≥0.01). Feeding cows PMR ration with maize silage significantly elevated total cholesterol (P&lt;0.05), but decreased urea levels in blood plasma (P&lt;0.01). It is concluded that strip cropping of sorghum and maize could be an alternative to maize grown as a pure stand in maize high-risk areas for dairy cows in mid-lactation.

Effect of silage from ryegrass intercropped with winter or common vetch for grazing dairy cows in small-scale dairy systems in Mexico

The objective was to determine the effect of including silages of annual ryegrass (Lolium multiflorum) intercropped with winter vetch (Vicia villosa) (ARG-VV) or with common vetch (Vicia sativa) (ARG-VS) compared with maize silage (MS) on milk yield and milk composition of dairy cows grazing cultivated perennial ryegrass-white clover pastures with supplemented concentrate during the dry season. Six Holstein dairy cows with a mean yield of 19.0 kg/cow/day at the beginning of the experiment were randomly assigned to a 3 × 3 repeated Latin square. Treatments were: 8 h/day intensive grazing, 3.6 kg of dry matter (DM) per cow per day of concentrate plus MS, and ARG-VV or ARG-VS ad libitum at a stocking rate of 3.0 cows/ha for three experimental periods of 3 weeks each. Milk yield (MY) and milk composition, live weight and body condition score as well as silage and concentrate intakes were recorded during the third week of each experimental period, and pasture intake was estimated indirectly from utilised metabolisable energy. Economic analysis was obtained by preparing partial budgets. There were no statistical differences (P > 0.10) in MY, milk fat or protein content nor for live weight, but there was significant difference (P < 0.10) in body condition score. There were non-statistical differences in silage DM intake (P < 0.11); however, significant differences (P < 0.10) were obtained for estimated grazed herbage intake whilst no differences for total DM intake. Slightly higher economic returns (10%) were obtained with ARG-VS over MS, and this was 7% higher than ARG-VV. It is concluded that ARG-VS could be an option for complementing grazing for small-scale dairy production systems in the dry season as it is comparable to MS in animal performance and slightly better in economic terms.

The Effect of Silage and Concentrate Type on Intake Behavior, Rumen Function, and Milk Production in Dairy Cows in Early and Late Lactation

The objective of this experiment was to evaluate the effect of feeding total mixed rations (TMR) that differ in structural and nonstructural carbohydrates to dairy cows in early and late lactation on short-term feed intake, dry matter intake (DMI), rumen fermentation variables, and milk yield. A 5×5 Latin square experiment with 15 dairy cows was repeated during early and late lactation. The 5 treatments were a TMR with (all on dry matter basis) 55% roughage (a 50:50 mixture of corn silage and grass silage) and 45% concentrate (a 50:50 mixture of concentrate rich in structural carbohydrates and concentrate rich in nonstructural carbohydrates; treatment CON), a TMR with the concentrate mixture and 55% grass silage (RGS) or 55% corn silage (RCS), and a TMR with the roughage mixture and 45% of the concentrate rich in structural carbohydrates (CSC) or the concentrate rich in nonstructural carbohydrates (CNS). Meal criteria, determined using the Gaussian-Gaussian-Weibull method per animal per treatment, showed an interaction between lactation stage and treatment. Feed intake behavior variables were therefore calculated with meal criteria per treatment-lactation stage combination. Differences in feed intake behavior were more pronounced between treatments differing in roughage composition than between treatments differing in concentrate composition, probably related to larger differences in chemical composition and particle size between corn silage and grass silage than between the 2 concentrates. The number of meals was similar between treatments, but eating time was greater in RGS (227 min/d) and lesser in RCS (177 min/d) than the other treatments. Intake rate increased when the amount of grass silage decreased, whereas meal duration decreased simultaneously. These effects were in line with a decreased DMI of the RGS diet vs. the other treatments, probably related to the high neutral detergent fiber (NDF) content. However, this effect was not found in CSC, although NDF content of the TMR, fractional clearance rate of NDF, and fractional degradation rate of NDF was similar between CSC and RGS. Rumen fluid pH was lesser, and molar proportions of acetic acid and of propionic acid were lesser and greater, respectively, in RCS compared with all other diets. Milk production did not differ between treatments. There was no effect of type of concentrate on milk composition, but diet RCS resulted in a lesser milk fat content and greater milk protein content than diet RGS. Lactation stage did affect short-term feed intake behavior and DMI, although different grass silages were fed during early and late lactation. The results indicate that short-term feed intake behavior is related to DMI and therefore may be a helpful tool in optimizing DMI and milk production in high-production dairy cows.

Mammary cell turnover and expression of lipogenic genes in response to silage induced CLA and diet energy density in lactating cows

The objective of this experiment was to investigate possible effects of silage induced differences in milk conjugated linoleic acids (CLA) and diet energy density on cell turnover and production capacity in the mammary gland. Cows were given high levels of canola fat and fed either grass or maize silage at either a high or a low diet energy density. Mammary biopsies were obtained and evaluated for cell turnover and gene expression. Diet energy density did not affect CLA concentration in milk fat and cell turnover. Feeding maize silage increased milk fat concentrations of cis9, trans11-CLA and trans10, cis12-CLA compared to grass silage. Cell proliferation tended to be greater in cows fed with maize compared to grass silage, indicating no negative effects of CLA on cell number. Feeding high energy density diets and maize silage diets tended to lower abundances of mammary lipogenic gene mRNAs presumable due to the effect of trans10, cis12-CLA.

The effect of silage and hay of regrowth timothy on the cellulolytic bacterial population in the rumen of reindeer

The effect of silage and hay of regrowth timothy on the cellulolytic bacterial population in the rumen of reindeer

The effect of silage and hay of regrowth timothy on the cellulolytic bacterial population in the rumen of reindeer

The effect of silage and hay of regrowth timothy on the cellulolytic bacterial population in the rumen of reindeer

Effect of silage:Concentrate ratio on feed intake, growth rate and subsequent milk yield of early calving heifers

The influence of silage:concentrate ratio (energy concentration) on voluntary feed intake, growth rate, feed utilization, reproduction and subsequent milk yield in early calving dairy heifers was examined. Forty-eight heifers of the breed Black and White were divided into four groups fed clover—grass silage and concentrates ad libitum in the ratios 100:0, 75:25, 50:50 and 25:75 of Scandinavian feed units (Sc.f.u.). Below 200 kg liveweight the daily intake of dry matter increased with increasing level of concentrates. Above 200 kg there were no significant differences in dry matter intake. As a consequence of the energy concentration of the rations (70, 78, 89 and 96 Sc.f.u. per 100 kg dry matter), the intake of net energy increased with the amount of concentrates, and consequently the daily gain increased. The increase in daily gain with concentrate level decreased with increasing liveweight. Puberty always occurred at the same liveweight, whereas age at first oestrus decreased with increasing content of concentrates in the ration offered ad libitum. This was reflected in a lowering of the age at first calving from 23.9 to 20.2 months. There was no significant difference in average milk yield in the first lactation. The milk yield was relatively low in all groups, and possible explanations for this depression are discussed.

A DAIRY RECORDS STUDY OF THE EFFECTS OF FEEDING LEVELS ON MILK YIELD AND COMPOSITION

A total of 139,720 Holstein and 17,259 Ayrshire 305-day lactation records from the Dairy Herd Analysis Service were studied to estimate linear and quadratic effects of net energy intakes from silage, hay, pasture and meal and effects of silage:hay ratio, roughage:meal ratio and energy concentration on milk yield and composition. Effects of correcting for feeding levels on estimates of herd and cow variance components were studied also. Linear effects of increased net energy intakes from silage, hay, pasture and meal on milk, fat and protein yields were positive (P &lt;.01) for both breeds. For Holsteins, all quadratic effects on milk yield were also positive (P &lt;.01). Quadratic effects of each roughage source on fat and protein yield were negative, but meal had a positive quadratic effect (P &lt;.01). Quadratic effects were inconsistent for the Ayrshires. Both linear and quadratic effects of feeding levels on fat and protein percent were inconsistent for the two breeds. For both breeds, greater silage:hay ratios and energy concentrations increased yields, and greater roughage:meal ratios decreased yields and fat percent (P &lt;.01). Correcting records for net energy intake reduced estimates of herd, cow and error variance components. Repeatability estimates of yield traits were also reduced, but percentage trait repeatabilities were not altered.

The effect of silage made from grass at different stages of maturity on the yield and composition of milk

SummaryIn cross-over experiments it has been established that milk yield increased and the fat solids-not-fat (SNF) contents of the milk decreased when cows were given approximately 15 lb dry matter/day of early-cut silage compared with the values obtained by giving the same amount of silage made from herbage cut at a later stage of maturity.Increasing the proportion of concentrates to silage in the cow's diet so that the milk yield remained unchanged increased the SNF content of the milk but had no effect on the fat content.Supplementing early-cut silage with 5 lb hay/day increased the fat content of the milk, but had no effect on either milk yield or the SNF content of the milk.Compared with a silage to which molasses had been added, untreated silage decreased milk yield, and increased the fat content without affecting the SNF content of the milk.