Concentrate Dry Matter Intake Research Articles

Performance of West African Dwarf (WAD) bucks fed differently processed poultry droppings

A 56 day trial was carried out to evaluate the response of West African Dwarf (WAD) bucks fed processed poultry dropping. Nine (9) West African Dwarf (WAD) bucks were assigned to three treatment groups in a completely randomized design (CRD) experiment with 3 bucks per treatment. The diets contained poultry dropping at 0% (T1), 10% sun dried poultry dropping (SDPD, T2) and 10% toasted poultry dropping (TPD, T3). The parameters evaluated included: dry matter intake (DMI), changes in body weight, feed conversion ratio (FCR), heart girth (HGC), body length (BLC) and height at withers, hematological and biochemical indices, and carcass characteristics of the bucks. Proximate analyses of the sun-dried poultry dropping, toasted poultry dropping, the treatment diets and the forages (Panicum maximum and Centrocema spp.) were also carried out. Concentrate dry matter intakes were 184.65g, 150.05g and 183.62g while forage dry matter intakes were 494.04g, 569.70g and 555.66g for T1, T2, and T3 respectively. Concentrate dry matter intake was similar (P>0.05) in T1 and T3 groups, but significantly (P<0.05) higher than the T2 group. The T2 group consumed significantly higher (P<0.05) forage than the T1 and T3 groups. HGC and HWC were 5.67cm, 2.33cm and 4.67cm, and 5.00cm 4.67cm and 4.00cm respectively. T1 and T3 had higher HGC than T2 group, while the T2 group recorded higher HWC than the T1 and T3 groups. The hemoglobin (Hb) values varied significantly (p<0.05) among the treatment means, and they were, 12.30, 11.30 and 12.00g/dl respectively. PCV (%) and WBC(x103/mm3 varied significantly (p<0.05) and the values were 37.00, 34.00 and 36.00 (%), and 39.00, 56.07 and 42.50(x103/mm3 respectively. Neutrophil and lymphocyte were also influenced significantly, the values were, 15.00, 10, and 31.00%, and 83.00, 86.00, and 66.00% respectively. Only serum urea was affected among the biochemical components, and the values were 0.87, 0.90 and 0.97 mg/dl respectively. Dressing percentage were 34.62%, 37.75% and 42.60% for T1, T2 and T3 respectively; the T2 and T3 groups were similar (P>0.05) but T3 was higher than T1. The values for shoulder were 10.67%, 10, 74% and 8.05%; the full gut values were 47.20% 38.56% and 28.68% for T1, T2 and T3 respectively. Liver, kidney and heart were 2.90%, 2.22% and 1.93%; 0.55, 0.47% and 0.42%, and 0.72%, 0.57% and 0.58% for T1, T2 and T3 respectively. T1 showed significantly (P<0.05) higher relative weight values for liver and heart than the T3 group. Inclusion of processed poultry dropping up to 10% in the diets of WAD bucks did not affect their performance negatively. However simple sun drying is recommended based on the results of this study and it is also a cheaper and straight forward processing method for poultry dropping.

Concentrate supplementation of a diet based on medium-quality grass silage for 4 weeks prepartum: Effects on cow performance, health, metabolic status, and immune function

Because negative energy balance (EB) contributes to transition-period immune dysfunction in dairy cows, dietary management strategies should aim to minimize negative EB during this time. Prepartum diets that oversupply energy may exacerbate negative EB in early lactation, with detrimental effects on immune function. However, with lower body condition score (BCS) cows, it has been shown that offering concentrates in addition to a grass silage-based diet when confined during an 8-wk dry period resulted in increased neutrophil function in early lactation. The aim of this study was to examine if similar benefits occur when concentrate feeding was restricted to a 4-wk period prepartum. Twenty-six multiparous and 22 primiparous Holstein-Friesian cows were offered ad libitum access to medium-quality grass silage until 28 d before their predicted calving dates (actual mean of 32 d prepartum; standard deviation = 6.4). At this time multiparous cows had a mean BCS of 2.9 (standard deviation = 0.12) and primiparous cows a mean BCS of 3.0 (standard deviation = 0.14) on a 1 to 5 scale. Cows were then allocated in a balanced manner to 1 of 2 treatments (13 multiparous cows and 11 primiparous cows on each treatment): silage only (SO) or silage plus concentrates (S+C) until calving. Cows on SO were offered the same grass silage ad libitum. Cows on S+C were offered an ad libitum mixed ration of the same grass silage and additional concentrates in a 60:40 dry matter (DM) ratio, which provided a mean concentrate DM intake (DMI) of 4.5 kg/cow per d. After calving, all cows were offered a common mixed ration (grass silage and concentrates, 40:60 DM ratio) for 70 d postpartum. Offering concentrates in addition to grass silage during the 4 wk prepartum increased prepartum DMI (12.0 versus 10.1 kg/cow per d), EB (+40.0 versus +10.6 MJ/cow per d), and body weight (BW; 640 versus 628 kg), and tended to increase BCS (3.02 versus 2.97). However, postpartum DMI, milk yield, milk composition, BW change, BCS change, serum nonesterified fatty acid, and β-hydroxybutryrate concentrations, health, and corpus luteum measures were unaffected by treatment. The in vitro assays of neutrophil phagocytosis, neutrophil oxidative burst, and interferon gamma production, conducted on blood samples obtained at d 14 prepartum and d 3, 7, 14, and 21 postpartum, were unaffected by treatment. Primiparous cows had higher phagocytic fluorescence intensity at d 14 prepartum and d 3 and 7 postpartum; a higher percentage of neutrophils undergoing oxidative burst at d 3, 7, and 21 postpartum; and a higher oxidative burst fluorescence intensity at d 14 prepartum and d 7, 14, and 21 postpartum compared with multiparous cows. This suggests that neutrophil function of primiparous cows was less sensitive to the changes occurring during the transition period than that of multiparous cows. In conclusion, offering concentrates during the 4-wk period prepartum had no effect on postpartum DMI, milk yield, body tissue mobilization, EB, measures of neutrophil or lymphocyte function, health, or corpus luteum activity.

Effect of concentrate supplementation during the dry period on colostrum quality and effect of colostrum feeding regimen on passive transfer of immunity, calf health, and performance

The objectives were to evaluate the effect of (1) supplementing concentrates to multiparous Holstein cows during the dry period on colostral and milk immunoglobulin G (IgG) concentration; and (2) feeding calves colostrum at either 5 or 10% of their body weight (BW) on passive transfer of immunity, health, and performance. Holstein multiparous cows (n=37) were assigned to 1 of 2 nutritional treatments during an 8-wk dry period: (1) offered ad libitum grass silage only (GS) or (2) offered ad libitum access to the same grass silage plus concentrate [total mixed ration in a 75:25 dry matter (DM) ratio], providing a mean concentrate DM intake of 3.0kg/cow per day (GSC). Both treatment groups were offered identical levels of mineral and vitamin supplementation. Calves from these cows were weighed immediately after birth and fed either 5% (5BW) or 10% (10BW) of their BW in colostrum from their own dams within 2.5h of birth. Calves in the 10BW group received their second feed of colostrum from first-milking colostrum. Concentrate supplementation during the dry period had no effect on colostral IgG concentration, first-milking IgG yield, or fat, protein, and lactose contents. However, cows in GSC produced a greater mean milk yield over the first 8 milkings compared with cows in the GS group. Concentrate supplementation had no effect on calf BW or BW gain, serum IgG, or apparent efficiency of absorption (AEA) at 24h after birth. However, offspring from the GSC group had fewer cases of enteritis during the first 56d of life compared with offspring from the GS group. Calves in the 10BW group had greater mean serum IgG concentration for the first 3d following birth; however, at 24h after birth, we observed no treatment effect on AEA. The rate of enteritis was greater for calves in the 5BW treatment compared with 10BW. The colostrum-feeding regimen had no effect on BW gain or on the incidence of pneumonia among calf treatment groups. In conclusion, concentrate supplementation regimens offered during the dry period had a positive effect on colostrum yield, and offspring from the GSC group had a reduced rate of enteritis. Feeding 10% of BW of colostrum versus 5% of BW resulted in a greater serum IgG concentration for the first 3d postpartum, and 10BW calves had a reduced rate of enteritis. Overall, to achieve successful passive transfer, decrease the rate of enteritis, and increase efficiency in the dairy calf, we recommend that dairy calves be fed 10% of their BW in colostrum as soon as possible after birth.

Prepartum concentrate supplementation of a diet based on medium-quality grass silage: Effects on performance, health, fertility, metabolic function, and immune function of low body condition score cows

When cows with a “higher” body condition score (BCS) are oversupplied with energy during the dry period, postpartum energy balance is normally reduced, which can have a detrimental effect on immune competence and increase the infectious disease risk. However, within grassland-based systems higher yielding cows frequently have a low BCS at drying off. The effects on performance, health, and metabolic and immune functions of providing additional energy to cows with low BCS during the dry period is less certain. To address this uncertainty, 53 multiparous Holstein-Friesian cows (mean BCS of 2.5; 1–5 scale) were allocated to 1 of 2 treatments at dry-off: silage only or silage plus concentrates. Cows on the silage-only treatment were offered ad libitum access to medium-quality grass silage. Cows on the silage-plus-concentrate treatment were offered ad libitum access to a mixed ration comprising the same grass silage plus concentrates [in a 75:25 dry matter (DM) ratio], which provided a mean concentrate DM intake of 3.0kg/cow per day. Postpartum, cows were offered a common mixed ration comprising grass silage and concentrates (in a 40:60 DM ratio) for a 70-d period. Offering concentrates during the dry period increased DM intake, tended to increase energy balance, and increased body weight (BW) and BCS gain prepartum. Offering concentrates during the dry period increased BW and BCS loss postpartum and tended to increase milk fat percentage and serum nonesterified fatty acid concentration, but it did not affect postpartum DM intake, energy balance, and milk yield. Although the percentage of phagocytosis-positive neutrophils did not differ, neutrophils from cows on the silage-plus-concentrate treatment had higher phagocytic fluorescence intensity at 1 and 2 wk postpartum and higher phagocytic index at 1 wk postpartum. Serum haptoglobin concentrations and IFN-γ production by pokeweed mitogen stimulated whole blood culture were unaffected by treatment, although haptoglobin concentrations increased and IFN-γ production decreased peripartum. Offering concentrates during the dry period increased the incidence of lameness postpartum, although other health and fertility parameters were unaffected. In conclusion, supplementing low BCS cows with concentrates during the dry period had no effect on performance and fertility and resulted in a higher neutrophil phagocytic index at 1 wk postpartum and an increased incidence of lameness compared with offering cows a grass silage–only diet prepartum.

Growth performance, carcass and non-carcass characteristics of Mubende and Mubende×Boer crossbred goats under different feeding regimes

A surge in the demand for goats׳ meat both locally and internationally has prompted many goat farmers in Uganda to venture into commercial goat production. However, goat production is highly challenged by breed characteristics and extreme fluctuations in feed quantity and quality. This study evaluated the effects of supplementing grazing Mubende goats and their crossbreds (Mubende×Boer) with concentrates on growth, carcass and non-carcass characteristics. A 2×3 factorial treatment arrangement was used to randomly allocate 96 pure Mubende and Mubende×Boer castrates (mean±SE; 31.3±2.2kg initial weight) aged between 9 and 15 months, to three feeding regimes. The feeding regimes included (i) sole grazing (SGZ) as control, (ii) control+concentrate containing molasses (MCM) and (iii) control+concentrate without molasses (MCC). Concentrate dry matter intake was higher (P<0.001) in the crossbreds regardless of concentrate type, however, inclusion of molasses resulted in lower concentrate intake. The Mubende goats were more efficient in utilising concentrate with molasses while the crossbreds utilised concentrate without molasses more efficiently. Average daily gain (ADG) was higher (P<0.001) in the crossbreds and in the supplemented groups. Slaughter weight, empty body weight and hot carcass weight were also higher (P<0.001) in the crossbreds than the pure Mubende. Supplementation reduced gut fill (P<0.001) and increased (P<0.001) hot carcass weight and dressing percentage in both genotypes. Proportion of non-carcass components as percentage of empty body weight did not vary between genotypes but supplementation reduced (P<0.01) proportion of skin with hocks and empty stomach. Kidney fat, omental fat and scrotal fat increased (P<0.001) with supplementation. Therefore, crossbreeding together with supplementation of grazing can considerably improve goat meat production, however, caution should be taken on the level of concentrate supplement offered as tendency for absolute substitution of concentrate for grass/browse by goats was observed in this study.

Effect of malate form (acid or disodium/calcium salt) supplementation on performance, ruminal parameters and blood metabolites of feedlot cattle

Heifers, 108, housed in 18 pens of 6/pen were used in a 141d feedlot study. Six pens were randomly assigned to each of the following experimental diets: CON: control (no additive); MA: CON plus 1.08kg/t of malic acid (0.98g of malate/g product); and MAL: CON plus 2kg/t of disodium/calcium malate (0.53g of malate/g product). Both additives provided 1.1g of malate/kg of concentrate (as mixed). Concentrate dry matter (DM) intake (kg/pen) and individual animal body weights (BW) were determined every 28d. At 0, 84 and 141d, ruminal fluid was obtained by ruminocentesis and blood samples were collected via tail venipuncture from 2 heifers/pen (12/diet). At slaughter, individual carcass weights were measured and carcass yield was determined. An in vitro study was also conducted to analyse ruminal fermentation of the 3 experimental diets. Batch cultures were inoculated with ruminal fluid from CON heifers incubated for 17h at 39°C, and main fermentation parameters were determined (i.e., pH, volatile fatty acids (VFA) and CH4 production, ammonia–N and lactate concentrations, and diet degradability). There were no differences among groups in BW, concentrate DM intake or BW gain at any time during the experiment. At slaughter, there were no differences in hot carcass weight and yield or carcass classification among groups. There were no effects of treatments on ruminal parameters (i.e., pH and concentrations of VFA and lactate), with the exception of NH3–N concentrations, which were higher (P<0.05) for MAL compared with CON and MA groups at 84d of sampling. Blood metabolites (i.e., glucose, urea–N, lactate) were unaffected by treatments. In the in vitro study, there were no differences among diets in any parameter measured. Under the conditions of this study, supplementation with MA or MAL had no effect on animal performance, ruminal parameters or blood metabolites, and results did not depend on whether malate was administered as the free acid or as the disodium–calcium salt.

Evaluation of concentrate factors affecting silage intake of dairy cows: a development of the relative total diet intake index

The aim of this work was to develop an index describing the relative intake of the total diet by dairy cows, and hence the ability to predict intake responses to changes in both forage and concentrate variables. An evaluation of concentrate factors affecting silage dry matter (DM) intake of dairy cows was conducted based on dietary treatment means from milk production experiments. The data were divided into four subsets according to concentrate treatments used within the experiments: the amount of concentrate supplementation (n = 217), protein supplementation (n = 336), carbohydrate composition (n = 114) and fat concentration of the concentrate (n = 29). The data were subjected to mixed-model regression analysis. Increased concentrate DM intake (CDMI) decreased silage DM intake (SDMI) quadratically. The substitution rate (substitution of silage DM for concentrate DM) increased with improved silage intake potential. SDMI increased quadratically with concentrate protein intake, the response being negatively related to the effective protein degradability (EPD) of concentrates. Replacement of starchy concentrate ingredients with fibrous supplements had a small positive effect on silage intake, whereas increased concentrate fat concentration slightly decreased SDMI. The outcome of concentrate factors influencing total DM intake (TDMI) was used to create a relative CDMI index as follows: CDMI index = 100 + 10 × [(CDMI − 0.1629 × CDMI − 0.01882 × CDMI2 − 5.49) + ((0.9474 × CCPI − 0.4965 × CCPI2) − 2.017 × (CEPD − 0.74)) + 0.00225 × (CNDF − 250) − 0.0103 × (40 − Cfat) − 0.00058 × (CDMI − 8.0) × (SDMI index − 100)], where CDMI = concentrate DM intake (kg/day), CCPI = supplementary concentrate CP intake (kg/day; CP>170 g/kg DM), CEPD = concentrate EPD (g/g), CNDF = concentrate NDF concentration (g/kg DM), Cfat = concentrate fat concentration (g/kg DM) and SDMI index is the relative intake potential of silage (Huhtanen, Rinne and Nousiainen 2007. Animal 1, 758–770). TDMI index was calculated as SDMI index + CDMI index − 100 to describe the relative intake potential of the total diet. For the whole data set (n = 943), one TDMI index unit was equivalent to 0.095 kg/day DM intake, i.e. close to the default value of 0.100 kg. The CDMI index explained proportionally 0.88 of the variation in TDMI within a study with a 0.27 kg/day residual mean-square error (n = 616). The corresponding values for the TDMI index were 0.81 and 0.37 kg/day (n = 943), respectively. The residual mean-square errors in cross-validation were marginally higher. The developed TDMI index can be used to estimate the intake responses to diet changes. It provides an improved basis for practical dairy cow ration formulation and economic evaluation.

The effect of cutting time of grass silage in primary growth and regrowth and the interactions between silage quality and concentrate level on milk production of dairy cows

Two silages were prepared from the primary growth (PG) of timothy-meadow fescue sward at early (E) and late (L) stage of growth. The subsequent regrowth (RG) areas were further harvested at early (EE and LE) and late (EL and LL) stages of growth resulting in six silages in total. The silages were fed ad libitum to 24 lactating Finnish Ayrshire cows and supplemented with 8 or 12 kg concentrate per day in a cyclic change-over experiment with four 21-day periods and 6 × 2 factorial arrangement of treatments. The quality of silages varied markedly within and between the harvests although variation was greater within PG than RG. Postponing the harvest in PG decreased silage dry matter (DM) intake by 0.48 kg and energy corrected milk yield (ECM) by 0.61 per 10 g decrease in silage D-value (concentration of digestible organic matter in DM), while responses and the range between the diets were clearly smaller when RG silages were fed. On average, ECM yield was higher when PG rather than RG silages were fed. The mean response to increased concentrate DM intake was 0.62 kg ECM using diets based on PG. The response increased with increasing growth stage of grass being 0.34 and 1.01 kg ECM / kg additional concentrate DM for E and L, respectively. The difference was mainly mediated by the differences in substitution rates (reduction in silage DM intake per increase in concentrate DM intake, kg/kg), which were 0.71 and 0.22 for E and L, respectively. The ECM response to increased concentrate allowance was on average greater when RG rather than PG silages (0.92 vs. 0.62 kg/kg concentrate) were fed. Milk production of dairy cows reflected the intake of metabolizable energy and no differences in the utilization of it were found between diets based on silages harvested from PG and RG. However, intake of RG silages was slightly lower than that of comparable PG silage, but definite reasons for that could not be identified.

Performance and behavior of dairy calves fed diets containing milk and citric flavor agents

While young ruminants prefer milk aroma and researches about this theme are being developed, the use of citric aroma, very appetized for older ruminants, are low utilized to young animals. This work aims to compare the influence of milk and citric flavor agents on the diets of nursing dairy calves. In this trial, 12 animals of Holstein breed were distributed in a randomized block design with four treatments (concentrate without flavor agent, concentrate with milk flavor or citrus flavor, and concentrate with milk plus citrus flavor agent) and three repetitions. The parameters evaluated were: concentrate dry matter intake (CDMI), hay dry matter (HDMI), milk dry matter intake (MDMI) and total dry matter intake (TDMI), average weight gain (ADWG), feed conversion (FC), initial (IBW) and final body weight (FBW), initial thoracic perimeter (ITP) and final thoracic perimeter (FTP), initial abdominal perimeter (IAP) and final abdominal perimeter (FAP), initial withers height (IWH) and final withers height (FWH) and animal behavior. The CDMI, HDMI and TDMI, as well as IBW, FBW, ITP, FTP, IAP, FAP, IWH and FWH did not show differences (P&gt;0.05). The averages daily gain and feed conversion showed no differences, with means of 0.55 kg/animal and 2.09, respectively. The diets did not affect animal behavior parameters (P&gt;0.05).

Growth and carcass characteristics of cast-for-age Merino ewes fed sorghum-based feedlot diets

Grain feeding low bodyweight, cast-for-age (CFA) sheep from pastoral areas of eastern Australia at the end of the growing season can enable critical carcass weight grades to be achieved and thus yield better economic returns. The aim of this work was to compare growth and carcass characteristics for CFA Merino ewes consuming either simple diets based on whole sorghum grain or commercial feed pellets. The experiment also compared various sources of additional nitrogen (N) for inclusion in sorghum diets and evaluated several introductory regimes. Seventeen ewes were killed initially to provide baseline carcass data and the remaining 301 ewes were gradually introduced to the concentrate diets over 14 days before being fed concentrates and wheaten hay ad libitum for 33 or 68 days. Concentrate treatments were: (i) commercial feed pellets, (ii) sorghum mix (SM; whole sorghum grain, limestone, salt and molasses) + urea and ammonium sulfate (SMU), (iii) SMU + whole cottonseed at 286 g/kg of concentrate dry matter (DM), (iv) SM + cottonseed meal at 139 g/kg of concentrate DM, (v) SMU + virginiamycin (20 mg/kg of concentrate) for the first 21 days of feeding, and (vi) whole cottonseed gradually replaced by SMU over the first 14 days of feeding. The target carcass weight of 18 kg was achieved after only 33 days on feed for the pellets and the SM + cottonseed meal diet. All other whole grain sorghum diets required between 33 and 68 days on feed to achieve the target carcass weight. Concentrates based on whole sorghum grain generally produced significantly (P &lt; 0.05) lower carcass weight and fat score than pellets and this may have been linked to the significantly (P &lt; 0.05) higher faecal starch concentrations for ewes consuming sorghum-based diets (270 v. 72 g/kg DM on day 51 of feeding for sorghum-based diets and pellets, respectively). Source of N in whole grain sorghum rations and special introductory regimes had no significant (P &gt; 0.05) effects on carcass weight or fat score of ewes with the exception of carcass weight for SMU + whole cottonseed being significantly lower than SM + cottonseed meal at day 33. Ewes finished on all diets produced acceptable carcasses although muscle pH was high in all ewe carcasses (average 5.8 and 5.7 at 33 and 68 days, respectively). There were no significant (P &gt; 0.05) differences between diets in concentrate DM intake, rumen fluid pH, meat colour score, fat colour score, eye muscle area, meat pH or meat temperature.

The effect of strain of Holstein-Friesian and feeding system on grazing behaviour, herbage intake and productivity in the first lactation

AbstractA comparative study of grazing behaviour, herbage intake and milk production was conducted using three strains of Holstein-Friesian (HF) heifer : 33 high production North American (HP), 33 high durability North American (HD) and 33 New Zealand (NZ) animals. Heifers were assigned, within strain, to one of three grass-based feeding systems : (1) the Moorepark (control) system (MP), (2) a high concentrate system (HC), (3) a high stocking rate system (HS). Strain of HF had no significant effect on grazing time or number of grazing bouts. The NZ strain had longer grazing bouts (P&lt; 0.01) and spent a lower proportion of time ruminating (P&lt; 0.05) than both the HP and HD strains. There was a significant strain ✕ feeding system interaction for biting rate. The biting rate of the NZ strain was reduced in the HC system. Biting rates in the HS feeding system were significantly higher (P&lt; 0.001) than in the MP system. Heifers on HC had shorter grazing time (P&lt; 0.01) with grazing bouts of shorter duration (P&lt; 0.01). Increasing stocking rate (HS) decreased the proportion of time ruminating (P&lt; 0.001) and tended to shorten grazing bouts (P = 0.06). The HP strain had higher (P&lt; 0.05) herbage and total dry matter (DM) intakes than the NZ strain, while the HD strain was intermediate. Concentrate supplementation reduced (P&lt; 0.001) herbage DM intake but increased (P&lt; 0.001) total DM intake. The reduction of herbage DM intake per kg of concentrate DM intake (substitution rate) was greater for the NZ than the HP strain. The HP produced significantly higher milk, fat, protein and lactose yields than the NZ, while the HD strain was intermediate. The milk fat content of the NZ was higher than both the HP and HD strains, while the protein content was higher than the HP strain. Concentrate supplementation (HC v . MP) significantly increased yields of milk and milk components. Milk production responses to the HC system were much greater with the HP than the NZ strain. Increasing stocking rate (MP v . HS) significantly decreased milk protein yield. The results indicate that the choice of strain of HF may depend on the feeding system.

Effects of increasing concentrate energy supply on the performance of loose-housed dairy cows fed grass silage-based diets

The effects of increased concentrate level on milk production was assessed during two consecutive indoor feeding seasons according to a continuous randomised block design using 44 (season 1) and 47 (season 2) Finnish Ayrshire cows. Treatments allocated according to a 2×2 factorial design consisted of two concentrate levels and two protein feeding systems. Low and high concentrate feeding regimens were applied to multiparous cows as 9 and 14 kg/day during days 1–150 of lactation and 8 and 11.5 kg for days 151–224, respectively. Primiparous cows received proportionately 0.80 of that fed to multiparous cows. In order to identify the effects of concentrate energy alone, concentrates were formulated so that increases in concentrate feeding resulted in either a constant supply of concentrate crude protein (CP) (mean 1.4 kg/day) or constant intake of rapeseed meal (RSM) (mean 1.7 kg DM/day). Consequently, concentrate CP content decreased with the increasing level of concentrate. Concentrate was offered through computerised self-feeders and silage was fed ad libitum. Increasing energy intake at a constant CP level seemed to have a more negative effect on silage dry matter (DM) intake compared with feeding a constant supply of RSM. Increases in concentrate DM intake resulted in mean substitution rates of 0.48 and 0.25 for CP and RSM diets, respectively. However, the positive effect of concentrate supplementation on milk yield was independent of protein feeding strategies. Milk production increased ( P<0.05) from 24.4 to 26.4 kg energy corrected milk (ECM) when energy level was increased, and on average 0.58 kg milk per kg increase in concentrate DM intake. The response to increased concentrate energy corresponded well with the responses reported earlier with a fixed concentrate composition. It is concluded that it was not possible to compensate a high amount of concentrate with low CP content with low amounts of concentrate with high CP content. However, feed utilization (ECM kg/kg DM) was more efficient for diets containing low amounts of concentrate. The ratio of milk nitrogen/feed nitrogen was highest when a high amount of concentrate with low CP content was used.

Prediction of voluntary intake of grass silages by lactating cows offered concentrates at a flat rate

ABSTRACTData for individually recorded silage dry-matter intake (SDMI), concentrate dry-matter intake (CDMI), live weight, milk yield and milk composition of lactating dairy cows offered silage ad libitum and concentrates on a flat-rate basis, together with data for silage composition from experiments conducted at four sites, were used to obtain simple and multiple regressions of SDMI on other variables.Simple regressions showed that the most important variables affecting SDMI were, in order of importance: silage ammonia nitrogen, fat yield, CDMI, silage digestible organic matter concentration (DOMD) and live weight. The best multiple regression for the mean SDMI over weeks 4 to 13 of lactation accounted for proportionately 0·649 of the variation. Examination of week by week data for weeks 3 to 20 of lactation showed that two models for early and mid lactation were required to give a reasonable pattern of residual variances. These models accounted for 0·627 and 0·581 of the variation respectively. It was necessary to fit time effects explicitly in early lactation. Live weight was best represented by fitting post-calving live weight and deviations from post-calving live weight separately. A number of models requiring fewer input variables were also obtained to allow for use in situations where the full range of measurements is not made.The new models were tested using independent data from three sites. They performed better than a number of previously published models but the best model still gave a prediction error of proportionately 0·17 about the mean actual silage intake in early lactation and 015 in late lactation.The results suggest that there is little to be gained from further refinement of the functional form of the models and that the construction of a number of models for specific food and management situations is preferable to the use of global models.

Prediction of the voluntary intake of grass silages by beef cattle. 1. Linear regression analyses

ABSTRACTData on individually recorded silage dry-matter intake (SDMI), concentrate dry-matter intake (CDMI) and live weight of steers and data on silage composition including toluene dry matter (TDM), pH, total nitrogen (N), ammonia nitrogen (NH3-N), volatile fatty acids (VFAs), digestible organic matter in the dry matter (DOMD) and neutral-detergent fibre (NDF) obtained from experiments conducted at three sites were used to obtain simple and multiple linear regressions of SDMI on other variables.Live weight accounted for a high proportion of the variation in intake but this effect could generally be removed by scaling intake by live weight raised to the power of 0·75 (M0·75). CDMI was the most important factor affecting scaled intake in mixed diets. TDM, NH,-N and VFAs all had important effects on SDMI. The relationship of SDMI with TDM was curvilinear suggesting that there is little to be gained in intake terms from wilting to TDM above 250 g/kg. The effect of NH3-N appeared to be related more to its correlation with VFAs than with any other nitrogenous constituent while the VFAs appeared to have a direct effect on SDMI. The effects of N and pH on SDMI were generally small. DOMD and NDF had relatively little effect on SDMI. Significant differences in intercepts between sites were found for most relationships although common slopes were often found.

EFFECTS OF FEEDING SODIUM BICARBONATE TO PREPARTUM DAIRY COWS ON THEIR PERFORMANCE IN EARLY LACTATION

Forty cows of second or greater parity were selected and blocked into 20 groups of two and randomly assigned to one of two prepartum diets; control prepartum (CP) or buffer prepartum (BP). The prepartum ration consisted of 85% grass hay, 10% ground corn and 5% dry cow supplement (dry basis). Sodium bicarbonate (NaHCO3) was fed at 0.6% of the total dry matter (DM) in the BP group. The postpartum ration was formulated to meet requirements for high-producing dairy cows in early lactation. Dry cows were placed on prepartum treatments 3 wk prior to expected calving date and abruptly switched to the postpartum ration on day 4 after parturition. For the first 4 wk of lactation the average daily total and concentrate DM intake as a percentage of body weight (BW) for cows fed rations BP and CP were not different. Forage intake as a percentage of BW and average production of 4% fat-corrected milk (FCM) was greater for CP than for BP. Milk fat test for CP and BP was not different. No differences were observed between CP and BP for rumen fluid parameters measured on days 14, 7 and 3 ± 2 prepartum. Total VFA (mg dL−1) and ratio of acetate-to-propionate was greater for CP than for BP; butyrate as a percentage of total VFA was greater for BP than for CP. Compared to controls, cows fed NaHCO3 prepartum did not perform as well during the first 4 wk postpartum as indicated by their lower forage intake and 4% FCM production. Key words: Sodium bicarbonate, cows (dairy), prepartum, performance

The effects of quantity and distribution of milk substitute on the performance and carcass measurements of artificially reared lambs

SUMMARYTwenty-seven groups of Finnish Landrace × Dorset Horn lambs each of 2 castrated males and 2 females were offered daily quantities of 180, 248 or 343 g of milk substitute dry matter (DM) for 21, 29 or 40 days. Concentrate pellets were available ad libitum and from 22 days of age 150 g of hay per week was offered. When the mean live weight of a group reached 35 kg two castrates and one female from each group were slaughtered and the carcasses appraised.The growth rate and daily concentrate intake of lambs from 48 days of age until slaughter (reported -in this paper) were not affected by previous treatment, but lambs weaned at 40 days had a higher food conversion efficiency in this period (0·266 kg gain/kg feed DM) than those weaned at 21 days (0·244) or 29 days (0·232).Delaying weaning from 21 to 29 and 40 days reduced overall concentrate DM intake from birth to slaughter (from 88·15 to 81·09 and 73·39 kg) but increased growth rate (261, 276 and 288 g/day) and the conversion of total DM consumed to live weight (0·300, 0·311 and 0·350 kg/kg). Increasing the daily allowance of milk substitute from 180 to 248 and 343 g/day also reduced total concentrate intake (84·18, 80·74 and 77·71 kg). Growth rate and food conversion efficiency tended to increase and concentrate DM intake to decrease when the same total quantity of milk substitute was given over a longer period. Castrated males grew faster than females (290 v. 260 g/day).Weaning age generally had a greater effect than daily allowance of milk substitute on carcass measurements. Fat in the carcass tended to increase with increasing weaning age and significant interactions between daily allowance of milk substitute and weaning age were found for some carcass measurements.