scholarly journals Efficiency of Crude Protein Utilisation in Grazing Dairy Cows: A Case Study Comparing Two Production Systems Differing in Intensification Level in New Zealand

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1036
Author(s):  
Martín Correa-Luna ◽  
Daniel Donaghy ◽  
Peter Kemp ◽  
Michael Schutz ◽  
Nicolas López-Villalobos
Keyword(s):  
Production System ◽  
Crude Protein ◽  
Production Systems ◽  
Live Weight ◽  
Total N ◽  
Protein Utilisation ◽  
Body Tissues ◽  
The Difference ◽  
Grazing Dairy Cows ◽  
Supplementary Feed

In this study, we modelled and compared lactation curves of efficiency of crude protein utilisation (ECPU) and the nitrogen (N) excreta partitioning of milking cows of two contrasting spring-calving pasture-based herds to test some aspects of farming intensification practices on cow performance and N partition. In the low-intensity production system (LIPS), 257 cows were milked once-daily and fed diets comprised of pasture with low supplementary feed inclusion during lactation (304 kg pasture silage/cow). In the high-intensity production system (HIPS), 207 cows were milked twice-daily and fed pasture with higher supplementary feed inclusion (429 kg pasture silage and 1695 kg concentrate/cow). The dietary crude protein (CP) utilisation was calculated for each cow at every herd test date as the ECPU as a proportion of protein yield (PY) from the CP intake (CPI) derived from intake assessments based on metabolisable energy requirements, and the CP balance (CPB) calculated as the difference between CPI and PY. Total N excreta partitioned to faeces (FN) and urine (UN) was estimated by back-calculating UN from FN, considering dietary N, and from N retained in body tissues, taking into account live weight change during the lactation. The higher CPI (2.7 vs. 2.5 kg CP/day), along with the reduced milk yield (1100 kg milk/cow less), of the LIPS cows led to a lower ECPU (23% vs. 31%) and to a higher CPB (2.1 vs. 1.8 kg CP/day) when compared to the HIPS cows. Mean N excreta, and particularly UN, was significantly higher in LIPS cows, and this was explained by higher dietary CP and by the reduced PY when compared to the HIPS cows. Reducing the low-CP supplementation in the “de-intensified” herd lessened the ECPU, resulting in higher UN, which is sensitive in terms of body water eutrophication.

Evaluation of a long-established silvopastoral Brachiaria decumbens system: plant characteristics and feeding value for cattle

2019 ◽  
Vol 70 (9) ◽  
pp. 814 ◽  
Author(s):  
Marina A. Lima ◽  
Domingos S. C. Paciullo ◽  
Fabyano F. Silva ◽  
Mirton J. F. Morenz ◽  
Carlos A. M. Gomide ◽  
...  
Keyword(s):  
Protein Content ◽  
Crude Protein ◽  
Nutritive Value ◽  
Production Systems ◽  
Crude Protein Content ◽  
Brachiaria Decumbens ◽  
Dairy Heifers ◽  
Feeding Value ◽  
Signal Grass ◽  
The Difference

One of the main challenges of using a silvopastoral system (SPS) is maintaining pasture and animal productivity over time. Our objective was to compare the productive characteristics and nutritive value of signal grass (Brachiaria decumbens cv. Basilisk) and the liveweight gain of dairy heifers in a SPS and open pasture (OP, signal grass under full sunlight) during the rainy seasons of four experiments between 2003 and 2016, which characterised systems from their 6th to 19th years after establishment in south-eastern Brazil when analysed together. The experimental design was a randomised complete block in a 2 × 4 factorial scheme (two production systems (SPS and OP) and four experiments (2003–2004, 2004–2007, 2011–2014 and 2014–2016)). From the 7th year onwards, the progressive reduction of photosynthetically active radiation negatively impacted the productive characteristics of the SPS pasture. Total forage mass was reduced by 19% in SPS compared with the OP in 2004–2007, 38% in 2011–2014 and 31% in 2014–2016. Crude protein content was 23% and 30% higher in the SPS than in the OP in 2011–2014 and 2014–2016, respectively. However, during the study period (until the 19th year), the liveweight gain of heifers was similar between systems since the higher crude protein content available in SPS contributed to improved forage nutritional value. From the 17th to the 19th year, weight gain per area was lower in the SPS compared with the OP (169 vs 199 kg ha–1), although the difference between systems was small. Signal grass presents a high degree of phenotypic plasticity in response to changes in shade levels, which gives this species a high potential for use in SPS.

Faecal index to estimate intake and digestibility in grazing sheep

2013 ◽  
Vol 152 (4) ◽  
pp. 667-674 ◽  
Author(s):  
D. B. DAVID ◽  
C. H. E. C. POLI ◽  
J. V. SAVIAN ◽  
G. A. AMARAL ◽  
E. B. AZEVEDO ◽  
...  
Keyword(s):  
Organic Matter ◽  
Linear Equation ◽  
Crude Protein ◽  
Live Weight ◽  
Regression Equations ◽  
Multiple Model ◽  
Sheep Grazing ◽  
Acid Detergent Fibre ◽  
The Difference ◽  
The Relationship

SUMMARYThe current research was carried out to evaluate the use of crude protein and fibre components in faeces for estimating intake and digestibility in sheep fed with pearl millet (Pennisetum americanum (L.) Leeke). The equations were developed from four trials in metabolism cages with 16 sheep in each trial. Each animal received a different quantity of millet leaves in the diet: 0·015, 0·020 and 0·025 dry matter (DM) as a proportion of live weight (LW) and ad libitum with at least 0·2 of daily feed refusals. Organic matter intake (OMI, g/day) was measured, through the difference between offer and refusals; total faeces were collected for 5 days, which was used to determine faecal crude protein (CPf, g/day and g/kg of organic matter (OM)), faecal neutral detergent fibre (NDFf, g/day and g/kg OM), faecal acid detergent fibre (ADFf, g/day and g/kg OM) and OM digestibility (OMD). Linear regression equations were calculated to determine the relationship between OMI and CPf (P<0·001, R2=0·90, relative prediction error (RPE=14·02%). A multiple linear equation was generated for OMI including CPf and NDFf (P<0·001, R2=0·94; RPE=9·25%). Hyperbolic (single and multiple) and exponential models were tested to estimate OMD, where the hyperbolic multiple model including CPf and NDFf showed lower RPE (3·90%). These equations for estimating OMI and OMD were evaluated on sheep grazing P. americanum fertilized with increasing levels of nitrogen (N) (50, 100, 200 and 400 kg N/ha), comparing measured and estimated OMI. The intake estimated by multiple regression (CP and NDFf) showed a higher R2 (0·98) and lower RPE (5·25%) than the simple (CPf only) linear equation (R2=0·94; RPE=20·45%). The results demonstrated the feasibility of using the faecal index generated in metabolism cages for estimating intake and digestibility in sheep grazing P. americanum.

scholarly journals Artificial rearing of pigs

1980 ◽  
Vol 44 (2) ◽  
pp. 171-178 ◽  
Author(s):  
M. J. Newport
Keyword(s):  
Small Intestine ◽  
Crude Protein ◽  
Skim Milk ◽  
Live Weight ◽  
Proximal Region ◽  
Soya Bean ◽  
Protein Digestion ◽  
Protein Nitrogen ◽  
Total N ◽  
Bean Protein

1. Pigs (twenty-one/diet) were weaned at 2 d of age and given liquid diets (200 g dry matter/l) at hourly intervals during a 26 d experiment. The pigs were fed on a scale based on live weight. The diets contained (g/kg DM): dried skim-milk 730 (diet A), dried whey 508·5, isolated soya-bean protein 218, DL-methionine 3·5 (diet S), and soya-bean oil 270 (diets A and S). Diet T contained equal proportions of diets A and S. Soya-bean supplied 0, 370 and 740 g crude protein (nitrogen × 6·25)/kg total crude protein in diets A, T and S respectively.2. Performance was similar for both diets A and T (P > 0·05). Pigs given diet S scoured severely, and fourteen died. The survivors grew very poorly. Nitrogen retention (g/d per kg live weight) was greater for diet A compared with diet T (P < 0·0r), and decreased with age (P < 0·01).3. Protein digestion was examined in the pigs killed at 28 d of age. The amount of soya-bean protein in the diet did not affect the amount of digesta in the stomach, but soya-bean protein decreased the pH, DM and total N content of the digesta (P < 0.01), and increased, though not significantly (P < 0·05), pepsin activity in the digesta and stomach tissue. Acid secretion into the stomach appeared to be enhanced in pigs given a diet containing soya-bean protein.4. Amounts of trypsin, chymotrypsin, total N and proportion of non-protein-N in the digesta from the small intestine were similar for both diets A and T. The amounts for both diets were greater in the distal compared with the proximal region of the small intestine (P < 0·05). Chymotrypsin activity in the pancreas was reduced (P < 0·05) in pigs given diet T, although this reduction did not seem to impair digestion in 28-d-old pigs. Trypsin activity in the pancreas was similar for both diets A and T.5. It seems likely that the neonatal pig does not have the digestive capacity to tolerate the large daily intakes of soya-bean protein when dried skim-milk was totally replaced in the diet (diet S). When half the dried skim-milk was replaced, protein digestion was not impaired in 28-d-old pigs.

scholarly journals Assay of Blood Mineral Profiles of Dairy Cows at Various Physiological Status, Seasons and Production Systems in Two Districts of East Shoa Zone, Oromia Region, Ethiopia

2020 ◽  
Author(s):  
Wondewsen Bekele ◽  
Gebeyehu Goshu ◽  
Berhan Tamir ◽  
Tilaye Demissie ◽  
Zemelak Sahle
Keyword(s):  
Serum Concentration ◽  
Dairy Cows ◽  
Production System ◽  
Serum Calcium Level ◽  
Critical Level ◽  
Production Systems ◽  
Serum Minerals ◽  
Significant Difference ◽  
The Mean ◽  
The Difference

This study was conducted in East Shoa Zone, Oromia Region, Ethiopia, to determine serum minerals of dairy cows at different season. The mineral assessed were Calcium (Ca), Magnesium (Mg), Phosphors (P), Iron (Fe), Copper (Cu), Cobalt (Co) and Zinc (Zn). The district and the production systems were selected purposively. A total of two hundred forty blood samples were collected. Blood serum was collected, digested and analyzed for minerals, using Atomic Absorption Spectrophotometer and Photoelectric colorimeter. The mean serum calcium level was 0.080 vs 0.082g/L for lactating and 0.090, vs 0.081gm/L for dry cows in both seasons, in Ada’a and Adama district, which was mean serum calcium level was very close to critical level (CL) or said to borderline. The mean serum phosphorus was 0.037vs 0.039 g/L) for lactating and 0.038 vs 0.037 gm/L for dry cows in both season in study districts. In general, in addition to Ca limited number of dairy cows were deficient for P, Cu and co. The difference in mean serum magnesium was significant (P less than 0.05) by production system, physiological state of the animals with seasons. Similarly, the difference in serum copper level was statistically significant (p less than 0.05) based on physiology of cows, production system and season. Iron serum concentration showed a significant difference (P less than 0.05) by season, physiology and production system. In case of Zinc and cobalt serum concentration showed a significant difference (p less than 0.05) between production system, physiological stat and season. It could be concluded that in the study area most serum minerals of dairy cows were either below the critical level or very near to the critical level. The variation in serum level of measured mineral was also significant in many cases. Therefore, it is necessary to supplement these deficient minerals to the ration of dairy cows to improve production, productivity, health and reproduction efficiency.

The Political Economy of Tourism and Approaches to Forecasting

2020 ◽  
Author(s):  
Bob McKercher ◽  
Bruce Prideaux
Keyword(s):  
Political Economy ◽  
Production System ◽  
Production Systems ◽  
National Income ◽  
The Political ◽  
Trade Law ◽  
Economic Production ◽  
Carbon Neutral ◽  
The Difference ◽  
The Many

While there is a vast literature on issues related to political economy, tourism scholars have generally paid little attention to this area of research. This chapter discusses some of the underlying debates related to political economy to provide a window into the fundamental role that economic forces play in the operation, sustainability and profitability of the global tourism system. In the near future, the need to transition to a carbon-neutral production system (see Chapter 15), and the immense difficulties that will be faced in reining in our increasing use of diminishing resources, will generate considerable discussion on the merits of various production systems such as Neoliberalism, socialism, neo-Marxism and post-Keynesian. This chapter also considers a range of models used to forecast tourism activity, a task that is an important element in future tourism investment and planning activities. The current production system is firmly embedded in the market driven capitalist system of economic production and for this reason, the following dis- cussion will focus on capitalism. This chapter provides a neo-Marxist perspective to demonstrate a counter view to the predominate interpretation of capitalism through a neoliberal lens. Degrowth (see Chapter 15) also offers another vision for organizing a future economic system of production. Understanding how we arrived at our system of economic production is important and provides insights into the next stage of economic evolution, which will most likely to be based on a carbon-neutral economic production system. So what is the difference between political economy and economics? Political economy is concerned with the process of production and its impact on national income and wealth, and the conflicts, inequalities and problems that arise in trade, law and government (Bianchi, 2018; Williams, 2004). Scholars generally approach the study of political economy from perspectives that include Liberalism, Keynesianism, Marxism, Socialism and Neoliberalism (and the many sub-branches of these schools). Economics on the other hand is concerned with production, distribution and consumption of goods and services and leaves aside political and social considerations although as Bianchi (2018) observed, the distinction between political economy and economics has become blurred because of the political nature of significant areas of neoliberal thought.

scholarly journals Carcass characteristics and meat quality attributes in lambs reared indoors, on cultivated pasture, or on semi-natural pasture

2020 ◽  
Vol 29 (5) ◽  
Author(s):  
Elin Stenberg ◽  
Anders Karlsson ◽  
Camilla Öghren ◽  
Katarina Arvidsson Segerkvist
Keyword(s):  
Weight Gain ◽  
Meat Quality ◽  
Production System ◽  
Production Systems ◽  
Live Weight ◽  
Intact Male ◽  
Live Weight Gain ◽  
Group 4 ◽  
Natural Pasture ◽  
Group 1

This study evaluated the effects of different lamb production systems on live weight gain (LWG), carcass quality and meat quality. Four production systems for weaned intact male lambs were examined: indoor feeding with grass silage and concentrate (group 1), grazing on cultivated pasture with (group 2) or without (group 3) concentrate, and grazing on semi-natural pasture (group 4). Live weight, carcass weight, dressing percentage, carcass conformation, fatness and pH decline were recorded at slaughter, and M. longissimus thoracis et lumborum was analysed for colour, thawing and cooking loss, pH after 24 hours and 6 days, and Warner-Bratzler shear force. LWG was strongly affected by production system, being highest for group 1 and lowest for group 4 (p<0.001). Group 4 had the lowest conformation (p=0.002) and fat scores (p<0.001). Hence, production system affected age at slaughter, live weight gain, weight at slaughter, carcass conformation and fatness scores, but caused no differences in meat quality attributes in intact male lambs.

Studies in grazing management IV. A comparison of close-folding and rotational grazing dairy cows on intensively fertilized pasture

1952 ◽  
Vol 42 (3) ◽  
pp. 304-313 ◽  
Author(s):  
W. Holmes ◽  
R. Waite ◽  
D. L. Fergusson ◽  
D. S. MacLusky
Keyword(s):  
Crude Protein ◽  
Harmful Effect ◽  
Live Weight ◽  
The Other ◽  
Rotational Grazing ◽  
Nitrogenous Fertilizer ◽  
Permanent Pasture ◽  
Regular Production ◽  
Digestible Crude Protein ◽  
Grazing Dairy Cows

1. In continuation of experiments made in 1949 (Holmes et al. 1950) an experiment was carried out from 7 May until 23 September 1950, to compare close-folding and rotational grazing of cows on pastures which were liberally treated with nitrogenous fertilizer. With close-folding the cows were moved daily to an area of fresh pasture calculated to supply the day's feed requirements; the rate of stocking for the day ranged from thirty to sixty-five cows per acre. With rotational grazing the cows were stocked on pasture at the rate of seven to eight cows per acre and moved from one pasture to the other at intervals of 3–4 days. Two uniform groups of six Ayrshire cows were used in a double reversal layout with four periods each of 5 weeks. The same pastures as in 1949—a permanent pasture and a cocksfoot ley—suitably divided by electric fences were used. No supplementary feeding was given.2. The average yield per acre from close-folding was 241 cow-days, 732 gal. of milk and 320 lb. live-weight gain—equivalent to 632 lb. digestible crude protein and 4316 lb. starch equivalent. Rotational grazing on similar adjoining paddocks gave 181 cow-days, 557 gal. of milk and 285 lb. liveweight gain per acre, equivalent to 486 lb. digestible crude protein and 3371 lb. starch equivalent.3. The average daily milk yield per cow was 29·5 lb. for one group and 30·2 lb. for the other. For close-folding it was 29·6 lb. and for rotational grazing it was 30·1 lb., none of the differences being significant. Nor were any differences in the average live weight of the groups or in their live-weight gains significant.4. The increased production per acre from closefolding compared with rotational grazing—amounting to 20–40%—could be related to the increased efficiency with which the available pasture was consumed.5. Close-folding had no harmful effect on the pastures. Although the season was exceptionally wet, poaching occurred only in the gates and alleyways. 6. The frequent applications of nitrogenous fertilizer throughout the season maintained regular production of good herbage. In June and July, however, despite the fertilizer applied, the crudeprotein content dropped on some paddocks to 13% of the dry matter, a figure barely sufficient to maintain high milk yields.7. Comparison of the production per acre in 1950 with that in 1949 where close-folding was used, showed an increase of 34% in starch equivalent utilized on the permanent pasture. For each extra cwt. ‘Nitro-Chalk’ applied in 1950 over that in 1949, 190 lb. starch equivalent were produced. On the cocksfoot the response to additional nitrogen was reduced because of potash deficiency induced by cropping for grass-drying in 1948.8. The factors affecting the increased production from close-folding and the fertilizer requirements of pasture are discussed.

The influence of high and low nutritional planes on the oestrous cycle and conception rate of heifers

1954 ◽  
Vol 45 (2) ◽  
pp. 164-172 ◽  
Author(s):  
D. M. Joubert
Keyword(s):  
Sexual Activity ◽  
Average Length ◽  
Post Partum ◽  
Live Weight ◽  
Late Summer ◽  
Normal Activity ◽  
Sexual Cycle ◽  
Nutritional Conditions ◽  
Body Tissues ◽  
The Difference

1. During the course of investigations on the influence of High- and Low-nutritional planes on the growth, reproduction and production of heifers, sexual activity was studied by recording oestrus data. A total of 239 observations were recorded for fourteen maiden heifers for each nutritional plane; 161 for the High-plane individuals and 78 for those on the Low plane. The investigation included four breeds, viz. Beef Shorthorn, Afrikaner, Friesian and Jersey.2. The average length of the dioestrous cycle was 20·16 days for the High-plane animals, and 20·83 days for their Low-plane counterparts, the difference of 0·67 days not being statistically significant. Breed differences were not very marked, but a tendency was revealed for the Friesians of both planes to have slightly longer cycles on an average than any other breed studied.3. The modal length of the cycle for both groups was found to be 19 days, with 95·6% of the cycles falling within the normal range of 17 to 23 days. Cycles exceeding 33 days in length were, however, excluded from these calculations.4. A tendency was revealed for the initial postpubertal cycles to be longer on an average than what is usually considered the normal length. Although the High-plane heifers settled down to a regular rhythm sooner, observations showed that differences existing between individual animals is probably of greater significance in this regard than any other factor.5. Whereas the majority of the High-plane heifers reached puberty during winter, 85·7% of the Lowplane heifers came on heat for the first time in summer. It is suggested that with the approach of favourable nutritional conditions, animals in a low condition first restore depleted body tissues before the sexual cycle returns to normal activity.6. A slight tendency was noticed for cycle length to vary with the season in the case of the High-plane animals, longer cycles being recorded in summer than in winter. On the Low plane, however, the heifers concerned invariably experienced an anoestrous condition during winter, lasting anything up to 218 days. Only after they regained the losses in live weight, was sexual activity restored as previously pointed out.7. Sexual activity was shown to be greatest in late summer with little variation over the remainder of the year under normal conditions of nutrition and management, while in the Low-plane individuals it fluctuated from complete inactivity in midwinter to a peak in summer.8. Post-partum oestrus was considerably delayed by lactation in the beef animals. The High plane heifers came on heat only after weaning their calves while the Low-plane individuals required nearly a year in addition to regain depleted body reserves before sexual activity was restored. The Low-plane dairy heifers showed a longer post-partum anoestrous period also, the difference between the two groups being 20·77 days.9. The results for the number of services required per conception demonstrated that the Low-nutritional plane caused no detrimental influence on this factor. In fact, the difference existing between the two groups studied was in favour of the Low plane animals. This is in agreement with Asdell's (1952) findings. It was shown that season had no effect on the results obtained.

Endogenous hormone and metabolite concentrations in different breeds of beef steer on two systems of production

1988 ◽  
Vol 47 (2) ◽  
pp. 231-244 ◽  
Author(s):  
J. M. Beeby ◽  
W. Haresign ◽  
H. Swan
Keyword(s):  
Growth Rate ◽  
Production System ◽  
Production Systems ◽  
Live Weight ◽  
Blood Samples ◽  
Wide Range ◽  
Breed Differences ◽  
Nitrogen Concentrations ◽  
Induced Changes ◽  
Beef Steer

ABSTRACTThe experiments were conducted to investigate the effect of sire breed and production system on serum GH, insulin, prolactin, glucose and blood urea nitrogen concentrations in growing beef cattle. A total of 187 steers, representing a wide range of maturity types, was reared to slaughter on either the 16-month or 24-month production systems in experiment 1, and blood samples for hormone and metabolite determinations were collected at 3-monthly intervals. Experiment 2 compared only the extremes of maturity type, with four early- and four late-maturing animals on each production system. Blood samples from these animals were collected hourly for 10 h on 2 or more consecutive days at six different time periods during the growth of the animals.Although significant between-breed differences in hormone concentrations were observed in experiment 1, there were no significant correlations between growth rate and circulating hormone concentrations. These results were largely borne out by the more detailed blood sampling used in experiment 2.Differences did occur in live-weight gain, GH and insulin concentrations between production systems, although these were largely determined by the induced changes resulting from the imposition of a store period on the animals produced through the 24-month production system.These results indicate that between-breed differences in growth rate cannot be accounted for by differences in circulating GH, insulin and prolactin concentrations. Rather, it appears that the hormones are primarily used to enable the animal to adjust its metabolism to changes in nutrient supply.

scholarly journals The effect of date of cut and barley substitution on gain and on the efficiency of utilization of grass silage by growing cattle

1988 ◽  
Vol 60 (2) ◽  
pp. 297-306 ◽  
Author(s):  
C. Thomas ◽  
B. G. Gibbs ◽  
D. E. Beever ◽  
B. R. Thurnham
Keyword(s):  
Crude Protein ◽  
Body Weight Gain ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Lactic Acid Content ◽  
Acid Detergent Fibre ◽  
Energy Retention ◽  
Gross Energy ◽  
Daily Allowance ◽  
The Difference

1. A primary growth of perennial ryegrass (Lolium perenne) was cut early or late to produce silages of high and low digestibility. The crops were wilted for 2–4 h and preserved with formic acid at 2.4 litres/t fresh weight. The resulting silages were well preserved with a pH of 3.9 and 3.8, lactic acid content of 108 and 73 g/kg dry matter (DM) and total nitrogen content of 24.6 and 18.4 g/kg DM for early- and late-cut silage respectively.2. Forty-two British Friesian male castrates (steers) initially 12 months of age and 305 kg live weight (LW) were used, of which ten were slaughtered at the start of the experiment. The remaining steers were divided into four groups of eight animals and were given the early-cut silage alone (H) or the late-cut silage alone (L) or with barley at either 280 (LCI) or 560 (LC2) g DM/kg total DM. The intake of total DM was restricted to a daily allowance of 18 g DM/kg LW and the steers were slaughtered in two groups after 119 and 140 d on experiment.3. Both earlier cutting of herbage and substitution of late-cut silage with barley significantly (P <0.001) increased the apparent digestibility of gross energy (H0.748, L0.619, LC10.668, LC20.705), whereas earlier cutting increased the digestibility of acid-detergent fibre from 0.638 (L) to 0.777 (H) and substitution with barley resulted in a significant (P <0.001) depression to 0.595 (LCI) and 0.519 (LC2). Substitution of late-cut silage with barley significantly (P <0.001) increased metabolizable energy (ME) intake from 58.9 (L) to 69.5 MJ/d (LC2) and crude protein (N × 6.25; CP) intake from 688 (L) to 779 g/d (LC2), but the highest intakes of ME and CP (73.5 MJ/d and 952 g/d respectively) were achieved with the early-cut silage.4. Earlier cutting resulted in significant (P <0.001) increases in body-weight gain from 292 to 696 g/d, fat gain from 121 to 260 g/d, protein gain from 31.1 to 86.9 g/d and energy retention from 5.5 to 12.2 MJ/d for silages L and H respectively. However, substitution of the late-cut silage with barley increased gains to a greater extent. Thus, empty-body gain was increased to 552 and 800 g/d, fat gain to 189 and 302 g/d, protein gain to 76 and 116 g/d and energy retention to 9.2 and 14.6 MJ/d for diets LCI and LC2 respectively. The difference in gains between diets H and LC2 achieved significance (P <0.05) for all components except fat.5. It is concluded that although earlier cutting of herbage for silage results in increased gains of protein and energy, the amounts retained are less than those from a similar increment of ME and CP achieved by substituting a late-cut silage with barley.

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