The effect of crop maturity on the nutritional value of maize silage for lactating dairy cows. 1. Energy and nitrogen utilization

2000 ◽  
Vol 71 (2) ◽  
pp. 381-390 ◽  
Author(s):  
S. B. Cammell ◽  
J. D. Sutton ◽  
D. E. Beever ◽  
D. J. Humphries ◽  
R. H. Phipps
Keyword(s):  
Starch Content ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Energy Output ◽  
Apparent Digestibility ◽  
Maize Silage ◽  
Forage Maize ◽  
Mean Values ◽  
Grass Silage ◽  
Crop Maturity

AbstractFour multiparous Holstein-Friesian cows fitted with simple cannulas in the proximal duodenum and the rumen were offered four diets in a 4 ✕ 4 Latin-square design to evaluate the effect on energy and nitrogen balance of crop maturity of maize when offered as ensiled food with grass silage and a concentrate. Forage maize (cv. Hudson) was ensiled at target dry matter (DM) contents of 230, 280, 330 and 380 g per kg fresh weight (FW). The mean values for volatile corrected DM (VCDM) and starch content of the maize forages as given were 226, 278, 319 and 357 g/kg FW and 180, 263, 327 and 401 g/kg VCDM respectively. Grass silage (GS) containing 247 g VCDM per kg FW was produced from the primary growth of a perennial ryegrass sward. The diets comprised 8·7 kg DM concentrate per day with one of four forage treatments offered ad libitum, in a 3 : 1 DM ratio of maize silage with GS, designated T23, T28, T33 and T38. Each period was of 6 weeks with energy and nitrogen balances conducted in respiration chambers over 6 days in either week 5 or 6. There were no significant effects of maturity on DM intake. Changes in milk yield and composition were not significant but milk protein yield increased significantly (P < 0·05) with maize maturity up to T33 and was linearly related (P < 0·05) to changes in maize silage starch and neutraland acid-detergent fibre (NDF, ADF) content. Total starch intake increased significantly (P < 0·01) with maturity but apparent digestibility of starch was significantly (P < 0·05) reduced only with the most mature maize silage (T38). NDF and ADF intake and amounts digested were not significantly different despite a numerical decline with stage of maturity. Total nitrogen intake and apparent digestibility were not significantly different although there were significant differences (P < 0·05) in the amount of nitrogen excreted as urine, which was greatest on T23 and least on T33, and milk which was least on T23 and greatest on T33. Mean gross energy (GE) intake increased by 17 MJ/day from T23 to T33 but the differences were non-significant. Faecal energy output on T23 was significantly lower (P < 0·05) than the other treatments whilst urine energy on T23 was significantly higher (P < 0·05) compared with T33. Methane energy losses were not significantly different. There were no significant differences between treatments in either GE digestibility or metabolizability, digestible or metabolizable energy (ME) intakes or in the partition of ME to heat, tissue or milk. The calculated ME concentrations of the maize silages were not significantly different with an overall mean of 12·3 MJ/kg VCDM estimated at maintenance intake, or 0·63 MJ/MJ GE. Changes in maize silage composition resulted in a doubling of the ratio of digested starch to digested NDF (0·66, 0·94, 1·10 and 1·21) for treatments T23 to T38 respectively. Despite this large change in digested nutrients no differences in the efficiency of energy utilization were detected.

The effect of crop maturity on the nutritional value of maize silage for lactating dairy cows. 2. Ruminal and post-ruminal digestion

2000 ◽  
Vol 71 (2) ◽  
pp. 391-400 ◽  
Author(s):  
J. D. Sutton ◽  
S. B. Cammell ◽  
R. H. Phipps ◽  
D. E. Beever ◽  
D. J. Humphries
Keyword(s):  
Starch Content ◽  
Latin Square ◽  
Caproic Acid ◽  
Individual Treatment ◽  
Maize Silage ◽  
Forage Maize ◽  
Mean Values ◽  
Holstein Friesian ◽  
Ruminal Digestion ◽  
Crop Maturity

AbstractTo evaluate the effect of crop maturity on digestion of maize silage in the rumen and post-ruminal digestive tract, four multiparous Holstein-Friesian cows fitted with a simple cannula in the proximal duodenum and a rumen cannula were offered four diets in a 4 ✕ 4 Latin-square design. Forage maize (cv. Hudson) was harvested and ensiled at target dry matter (DM) contents of 230, 280, 330 and 380 g per kg fresh weight (FW) to provide a range of starch contents. The mean values for volatile-corrected DM (VCDM) and starch content of the four maize silages as given were 221, 277, 308 and 372 g/kg FW and 173, 257, 328 and 382 g/kg VCDM respectively. Grass silage (GS) containing 250 g VCDM per kg FW was produced from the primary growth of a perennial ryegrass sward. The diets were 8·7 kg DM per day of a dairy concentrate supplement with one of four forage treatments offered ad libitum. The forage treatments were a 3 : 1 DM ratio of maize silage with GS, designated as T23, T28, T33 and T38. Each period lasted 6 weeks with rumen and duodenal samples being taken over 3 days in week 4 and faeces being collected in respiration chambers over 6 days in either week 5 or 6. Milk yield tended to increase with advancing maturity (30·5, 31·8, 32·5 and 32·3 kg/day) but individual treatment differences were not significant. DM intake increased from 19·62 to 21·30 kg/day (P < 0·05) but there were no significant effects on digestibility in the rumen, post-ruminal tract or total tract. Digestibility of neutral detergent fibre in the rumen declined with increasing starch content in the maize silage (P < 0·05) but total digestibility was not significantly affected. Starch intake increased from 3·11 to 5·04 kg/day (P < 0·001), duodenal flow from 0·40 to 0·89 kg/day (P < 0·01) and the amounts digested in the rumen and post-ruminal tract respectively from 2·72 and 0·34 kg/day to 4·16 and 0·71 kg/ day (P < 0·01). However the only significant effect on starch digestibility was a small fall in total digestibility from a mean of 0·981 for T23, T28 and T33 to 0·966 for T38. There were no treatment effects on nitrogen digestion. The molar proportions of acetic acid and n-caproic acid decreased and that of n-butyric acid increased with advancing maturity. It is concluded that the changes in composition of maize silage with increasing maturity result in large increases in the contribution of starch to DM digested in the rumen but only small differences in rumen fermentation. Post-ruminal starch digestion doubles but this is due to the increased starch concentration of the silage rather than major changes in digestion and the amount is small compared with that likely to result from feeding maize grain.

The effects of wilting of grass prior to ensiling on the response to bacterial inoculation. 1. Silage fermentation and nutrient utilization over three harvests

1996 ◽  
Vol 62 (3) ◽  
pp. 405-417 ◽  
Author(s):  
T. Yan ◽  
D. C. Patterson ◽  
F. J. Gordon ◽  
M. G. Porter
Keyword(s):  
Heat Production ◽  
Nutrient Utilization ◽  
Period Change ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Energy Output ◽  
Apparent Digestibility ◽  
Total N ◽  
Silage Fermentation ◽  
The Mean

AbstractFour silages were prepared from perennial ryegrass swards at each of first (primary growth), second (first regrowth) and third (second regrowth) harvests during the 1993 growing season. At each harvest the four silages included two unwilted (without and with inoculant at 2·4 l/t) and two wilted (without and with inoculant at 24 l/t). The four silages within a single harvest, were offered as the total diet at maintenance levels to 12 wether sheep for 3 weeks to determine nutrient apparent digestibilities. They were also given to 12 lactating dairy coivs together with a concentrate supplement, in a three-period change-over study with experimental periods of 8-weeks duration, to examine dry matter (DM) apparent digestibility and utilization of nitrogen (N) and energy in the diets.Inoculation tended to improve silage fermentation with on average lower pH and ammonia-N/total-N across the three harvests, while wilting of grass prior to ensiling significantly increased silage pH fP < 0·001) and ammonia-N/total-N (P < 0·001). Neither inoculation nor wilting had any significant effect on mean nutrient apparent digestibilities, assessed through sheep, across the three harvests. However, at the second harvest inoculation significantly reduced apparent digestibilities of DM (P < 0·001) and N (P < 0·001). At this harvest, wilting also significantly decreased apparent digestibilities of DM (P<0·05) and N (P <0·01), but significantly increased apparent digestibilities of DM (P < 0·05), energy (P < 0·001) and N (F < 0·05) at the third harvest. When the silages were offered as mixed diets to dairy cattle, neither inoculation nor wilting had significant effects on digestibilities of DM, N and energy at any of the three harvests, except for wilting which significantly decreased DM apparent digestibilities (P < 0·05) at the second harvest. However, the mean apparent digestibilities of DM (P < 0·01), N (P < 0·05) and energy (P < 0·01) across the three harvests were significantly lower following wilting, and N apparent digestibility (P < 0·05) was significantly higher following inoculation. The calorimetric data indicated that inoculaton had no significant effects on either methane energy output or heat production. Wilting also had no significant effect on methane energy output, but significantly increased daily heat production (P<0·05) at the first harvest. The efficiencies of metabolizable energy utilization for lactation (k1) were similar between the four silages at each of the first and second harvests, with the average being 0·50. The results of the present study indicated that inoculation tended to improve silage fermentation and significantly increased mean N apparent digestibility of mixed diets across the three harvests, while wilting significantly reduced mean DM, N and energy apparent digestibilities of mixed diets. Neither inoculation nor wilting had significant effects on Rvalue.

scholarly journals Prevalence of Mycotoxins and Endotoxins in Total Mixed Rations and Different Types of Ensiled Forages for Dairy Cows in Lithuania

Toxins ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 890
Author(s):  
Gintarė Vaičiulienė ◽  
Bronius Bakutis ◽  
Jurgita Jovaišienė ◽  
Rimvydas Falkauskas ◽  
Gediminas Gerulis ◽  
...  
Keyword(s):  
Dairy Cows ◽  
High Performance ◽  
Mean Value ◽  
The European Union ◽  
Maize Silage ◽  
Forage Maize ◽  
Mean Values ◽  
Grass Silage ◽  
Different Types ◽  
Concentration Limits

In this study, 119 samples of total mixed rations and different types of ensiled forage (maize and grass silage, and haylage) collected in 2019–2020 from dairy farms in Lithuania were analyzed to evaluate the quantitative occurrence of mycotoxins and endotoxins. Samples were analyzed using high-performance liquid chromatography (HPLC) with a fluorescent (FLD) and an ultraviolet detector (UV) of mycotoxins and a detection assay based on the ELISA technology for endotoxins. The study included toxins regulated within the European Union (aflatoxin B1 (AFB1), zearalenone (ZEA), deoxynivalenol (DON) and T-2 toxin) and nonregulated toxins (endotoxins). Mycotoxin analysis showed that 49.58% of the samples out of 119 were positive for AFB1, 52.11% for ZEA and DON, 55.47% for T-2 toxin and 84.04% for endotoxins. In the contaminated samples, the highest mean values of AFB1 and T-2 toxin were determined in the grass silage samples, while ZEA and DON–were determined in the maize silage samples. Maize silage samples had the highest ZEA and DON concentrations, exceeding the EU maximum permissible concentration limits. In the haylage samples, AFB1 mycotoxin exceeded the maximum concentration limits. The highest mean value of endotoxins was determined in the total mixed rations samples. This is the first study to provide information about the concentrations of mycotoxins and endotoxins in total mixed rations and different types of ensiled forages for dairy cows in Lithuania.

The effect of genetic merit and concentrate proportion in the diet on nutrient utilization by lactating dairy cows

1999 ◽  
Vol 132 (4) ◽  
pp. 483-490 ◽  
Author(s):  
C. P. FERRIS ◽  
F. J. GORDON ◽  
D. C. PATTERSON ◽  
M. G. PORTER ◽  
T. YAN
Keyword(s):  
Dairy Cows ◽  
Energy Intake ◽  
Milk Production ◽  
Milk Fat ◽  
Nutrient Utilization ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Energy Output ◽  
Genetic Merit ◽  
Gross Energy

Sixty Holstein/Friesian dairy cows, 28 of high genetic merit and 32 of medium genetic merit, were used in a continuous design, 2 (cow genotypes)×4 (concentrate proportion in diet) factorial experiment. High and medium merit animals had Predicted Transmitting Abilities for milk fat plus protein yield, calculated using 1995 as the base year (PTA95 fat plus protein), of 43·3 kg and 1·0 kg respectively. Concentrate proportions in the diet were 0·37, 0·48, 0·59 and 0·70 of total dry matter (DM), with the remainder of the diet being grass silage. During this milk production trial, 24 of these animals, 12 from each genetic merit, representing three animals from each concentrate treatment, were subject to ration digestibility, and nitrogen and energy utilization studies. In addition, the efficiency of energy utilization during the milk production trial was calculated.There were no genotype×concentrate level interactions for any of the variables measured (P>0·05). Neither genetic merit nor concentrate proportion in the diet influenced the digestibility of either the DM or energy components of the ration (P>0·05). When expressed as a proportion of nitrogen intake, medium merit cows exhibited a higher urinary nitrogen output and a lower milk nitrogen output than the high merit cows. Methane energy output, when expressed as a proportion of gross energy intake, was higher for the medium than high merit cows (P<0·05), while urinary energy output tended to decrease with increasing proportion of concentrate in the diet (P<0·05). In the calorimetric studies, neither heat energy production, milk energy output and energy retained, when expressed as a proportion of metabolizable energy intake, nor the efficiency of lactation (kl), were affected by either cow genotype or concentrate proportion in the diet (P>0·05). However when kl was calculated using the production data from the milk production trial the high merit cows were found to have significantly higher kl values than the medium merit cows (0·64 v. 0·59, P<0·05) while k l tended to fall with increasing proportion of concentrate in the ration (P<0·05). However in view of the many assumptions which were used in these latter calculations, a cautious interpretation is required.

Effects of supplementing maize and grass silages with barley, and maize silage with urea or ammonia, on the intake and performance of fattening bulls

1980 ◽  
Vol 31 (3) ◽  
pp. 243-250 ◽  
Author(s):  
K. Aston ◽  
J. C. Tayler
Keyword(s):  
Weight Gain ◽  
Dry Matter ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Dry Matter Intake ◽  
Carcass Quality ◽  
Maize Silage ◽  
Live Weight Gain ◽  
Grass Silage ◽  
Ad Libitum

ABSTRACT1. Experiment 1. Six treatment groups of one British Friesian and four South Devon × British Friesian bulls, initially 432 kg mean live weight and aged 491 days, were offered individually maize or grass silage ad libitum plus 0, 5 or 10g barley dry matter per kg live weight daily for 80 days. The silages had similar digestible dry matter and estimated metabolizable energy contents but the grass silage contained more ammonia and acetic, propionic and butyric acids. Mean values for groups receiving respectively maize and grass silage diets were for dry-matter intake 17·7, 20·3, 20·4 and 13·0, 16·6, 18·7 g/kg live weight and for live-weight gain 1·00, 1·32, 1·46 and 0·65, 0·98, 1·22kg/day. Significantly more maize than grass silage dry matter was eaten when the silages were given alone and dry-matter intakes, live-weight and carcass gains were greater for maize silage diets. Dry-matter intake, live-weight and carcass gains, efficiency of feed use and carcass quality significantly improved when barley was given.2. Experiment 2. Six groups of five British Friesian bulls, initially 418 kg mean live weight and aged 474 days, were offered individually maize silage ad libitum with either urea or one of two quantities of aqueous ammonia mixed in at the time of feeding, plus 0 or 5 g barley dry matter per kg live weight daily for 90 days. The urea and ammonia-treated silages contained 125, 124 and 148 g crude protein per kg dry matter respectively, with pH values of 3·8, 3·9 and 4·3, and when given alone or with barley mean daily intakes (g dry matter per kg live weight) were 17·1, 18·6 for urea-treated silage diets, and 17·8, 18·8 and 16·9, 19·1 respectively for ammoniatreated silage diets. Live-weight gains were 0·69, 0·94, 0·63, 1·09, 0·64 and 1·07 kg/day. Ammonia treatment had no effect on intake or live-weight gain. Live-weight and carcass gains and carcass quality improved when barley was given.3. The maize silage offered in Experiment 1 contained similar metabolizable energy but more starch than that in Experiment 2 and was used more efficiently for live-weight gain.

An examination of energy utilization in lactating dairy cows receiving a total mixed ration based on maize silage

2000 ◽  
Vol 71 (3) ◽  
pp. 585-596 ◽  
Author(s):  
S. B. Cammell ◽  
D. E. Beever ◽  
J. D. Sutton ◽  
J. France ◽  
the late G. Alderman ◽  
...  
Keyword(s):  
Mean Value ◽  
Open Circuit ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Repeated Measure ◽  
Maize Silage ◽  
Individual Values ◽  
Total Mixed Ration ◽  
Stage Of Lactation ◽  
The Mean

AbstractSix multiparous Holstein-Friesian cows were offered a total mixed ration based on maize silage in a repeated measure design to evaluate the partition of gross energy (GE) during early to mid lactation. Four measurements were made at 6-week intervals with energy and nitrogen balances carried out in open-circuit respiration chambers over 6 days during lactation weeks 6, 12, 18 and 24. The intakes of total diet dry matter (DM) corrected for volatile losses (VCDM), organic matter (OM) and GE declined significantly (P< 0•01) as lactation progressed, although apparent digestibility of these fractions was not altered, resulting in a significant (P< 0•01) decline in digestible nutrient intake at each stage of lactation. Methane and urine energy losses were not significantly affected, resulting in significantly (P< 0·001) higher amounts of digestible energy (DE) partitioned to methane and urine as lactation progressed with associated significant reductions in metabolizable energy (ME) intake (MEI) (P< 0·01) and ME as a proportion of DE (P< 0·001) and GE (q) (P< 0·05). With advancing lactation there was a significant (P< 0·001) increase in the amount of ME partitioned to heat (HP/MEI), but no significant change in the amount partitioned to milk and tissue. Individual values for diet metabolizability (ME/GE) at actual (production) levels (qa) (mean 0·625 MJ/MJ) were corrected to an equivalent value at maintenance (qmc) (mean 0·666 MJ/MJ). The overall ME intakes (MJ/day) were: ad libitum, 246, corrected for level of feeding effect, 263, with a predicted ME requirement according to AFRC (1993) (MER93) of 242. Substitution of the calculated qmc into the predictive equations (AFRC, 1993) resulted in a mean maintenance requirement of 57·6 MJ/day (0·464 MJ/kg M0·75/day) whilst the mean value derived from the linear model describing the experimental data was 82·5 MJ/day (0·664 MJ/kg M0·75/day). The mean efficiencies of utilization of ME for milk production derived from AFRC (1993) and the linear regression model were 0·653 MJ/MJ and 0·625 MJ/MJ respectively.

Granadina kid goats v. Segureña lambs: food intake and performance during milk feeding from birth to 60 days

1994 ◽  
Vol 58 (2) ◽  
pp. 257-261 ◽  
Author(s):  
M. R. Sanz Sampelayo ◽  
I. Prieto ◽  
L. Lara ◽  
F. Gil Extremera ◽  
J. Boza
Keyword(s):  
Body Weight ◽  
Dry Matter ◽  
Metabolizable Energy ◽  
Milk Replacer ◽  
Morphological Development ◽  
Apparent Digestibility ◽  
Mean Values ◽  
Energy Retention ◽  
And Performance ◽  
Milk Feeding

AbstractThe morphological development of the sheep and the goat is different and this difference is manifested from early post-natal life. The main characteristic of kid goat carcasses is their low adipose tissue, and this is considered detrimental to quality. In an attempt to determine the nutritional causes of this, a study was performed with kid goats of the Granadina breed and lambs of the Segureña breed. Six kid goats and six lambs were slaughtered at birth, while a further eight kids and eight lambs were fed a milk replacer to satiety until the 60th day of life and slaughtered on the 61st day. Dry matter (DM) and metabolizable energy (ME) intakes and apparent digestibility of energy were determined in four balance periods between 8 and 60 days of life. From the intakes of ME and comparative slaughter data it was possible to calculate energy retention (ER), heat loss (HL) and energy retained as protein (ERp) and as fat (ERf) for kids and lambs. Kid goats showed a similar apparent digestibility of energy to lambs but had lower DM and ME intakes per kg metabolic body weight (M0·75) than lambs. For kids and lambs respectively these values were: 0·93 and 0·94; 45·4 and 50·1 g/kg M0·75 per day; 937 and 1033 kJ/kg M0·75 per day. Mean values for ER, HL, ERp and ERf rates were: 263, 674, 131 and 132 kJ/kg M0·75 per day for kid goats and, 343, 690, 132 and 211 kJ/kg M0·75 per day for lambs. Together with the different intake, kid goats showed a lower rate of ER and overall, a lower rate of ERf than lambs.

Intake, growth rate and carcass quality of beef cattle fed maize silage harvested at three stages of maturity

1999 ◽  
Vol 1999 ◽  
pp. 83-83 ◽  
Author(s):  
E.M. Browne ◽  
M.J. Bryant ◽  
D.E. Beever
Keyword(s):  
Beef Cattle ◽  
Live Weight ◽  
Carcass Quality ◽  
Maize Silage ◽  
Forage Maize ◽  
Significant Depression ◽  
Three Stages ◽  
Finishing Beef Cattle ◽  
Crop Maturity

Crop maturity at harvest affects the intake potential of maize silage. A short feeding trial with young beef heifers (Browne, Bryant, Beever and Thorp, 1998) identified a significant depression in intake when low DM silage was fed, yet no significant effect on live weight gain was recorded. The objective of this experiment was to determine if these results were repeated in a longer intake study using finishing beef cattle and to examine the effect of maize maturity on carcass quality.Forage maize was harvested at three stages of maturity (LOW, MED and HIGH) during September 1997. At each stage of maturity, the crop was cut and ensiled in a separate AgBag during one day, without the use of an additive. The respective silage DM concentrations were 297, 339 and 393 g/kgFWt.

The effect of crop maturity on the nutritional value of maize silage for lactating dairy cows. 3. Food intake and milk production

2000 ◽  
Vol 71 (2) ◽  
pp. 401-409 ◽  
Author(s):  
R. H. Phipps ◽  
J. D. Sutton ◽  
D. E. Beever ◽  
A. K. Jones
Keyword(s):  
Food Intake ◽  
Protein Content ◽  
Milk Production ◽  
Milk Yield ◽  
Milk Protein ◽  
Protein Yield ◽  
Maize Silage ◽  
Grass Silage ◽  
Milk Protein Content ◽  
Crop Maturity

AbstractFifty-five multiparous Holstein-Friesian cows were used in a 20-week continuous design study to determine the effect of maize silage maturity on food intake and milk production. Forage maize (cv. Hudson) was harvested and ensiled at target dry matter (DM) contents of 230 (T23), 280 (T28), 330 (T33) and 380 (T38) g per kg fresh weight (FW). The mean values for volatile-corrected DM (VCDM), starch, neutral-detergent fibre (NDF), crude protein and predicted metabolizable energy (ME) content of the four maize silages were 226, 290, 302 and 390 g/kg FW, 114, 274, 309 and 354 g/kg VCDM, 574, 447, 431 and 448 g/kg VCDM, 96, 80, 74 and 75 g/kg VCDM and 10·3, 11·5, 11·6 and 11·2 MJ/kg DM, respectively. Grass silage containing 296 g VCDM per kg FW was produced from the primary growth of a perennial ryegrass sward. At week 3 of lactation cows were allocated to one of five forage treatments offered ad libitum. The forage treatments were either grass silage alone (TGS) or a 3 : 1 DM ratio of maize and grass silage designated as T23, T28, T33 and T38. All cows also received 8·7 kg DM per day of a dairy concentrate. Forage VCDM intake for TGS was lower (P < 0·001) than for T23 to T38. Increasing maize silage DM content from 226 (T23) to 290 (T28) g/kg increased (P < 0·05) forage VCDM intake from 10·9 to 13·3 kg/day but a further increase to 390 (T38) g/kg tended to reduce VCDM intake. When compared with TGS, the inclusion of maize silage increased milk yield from 28·0 kg/day to 29·4, 32·7, 33·0 and 30·8 kg/day for T23 to T38, respectively, the increases being significant for T28 to T38. However, milk yield was reduced (P < 0·05) when the DM content of the maize silage increased from 302 to 390 g/kg. Increasing maize silage DM content from T23 to T33 reduced (P < 0·05) milk fat content from 45·8 to 41·8 g/kg, which was also lower (P < 0·05) than for TGS. The inclusion of maize silage increased fat yield with a significant difference (P < 0·05) between TGS and T28. The inclusion of maize silage increased milk protein content (P < 0·05) and protein yield (P < 0·001) when compared with TGS. While increasing maize silage maturity did not affect (P > 0·05) milk protein content, protein yield was higher (P < 0·05) for the two intermediate DM contents. There were no treatment effects on body condition score. It is concluded that the changes in composition of maize silage with increasing maturity, which are associated with increased starch and reduced NDF content, resulted in large increases in food intake and yield of milk and protein as crops matured from T23 to T33. However, when crop maturity increased further to T38 there was a tendency for DM intake and yield of milk and protein to decline.

scholarly journals EFFECTS OF POPULATION DENSITY ON ENERGY UTILIZATION, INTESTINAL DISACCHARIDASES, AND ADRENAL FUNCTION IN HENS

1972 ◽  
Vol 52 (1) ◽  
pp. 103-112 ◽  
Author(s):  
K. Y. LEI ◽  
M. P. STEFANOVIC ◽  
S. J. SLINGER
Keyword(s):  
Fatty Acids ◽  
Population Density ◽  
Egg Production ◽  
Starch Content ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Feed Consumption ◽  
Bird Density ◽  
Total Fatty Acids ◽  
Adrenal Corticosterone

Two experiments were carried out with laying hens to determine the effect of overcrowding stress on reproductive performance and on certain other parameters that might be expected to be affected and thus be useful indices of this type of stress. The first experiment consisted of eight treatments in a factorial arrangement with four bird densities of one, two, three, or four birds in 30.5 × 45.7-cm (12 × 18″) cages and two levels of dietary energy. The second experiment involved three bird densities of one, three, and five birds in 30.5 × 45.7-cm cages fed a single diet. There were four replicate cages per treatment in both experiments. Feed consumption, weight gain, and egg production were not significantly affected by the population densities employed in experiment 1. In experiment 2, increasing bird density significantly reduced egg production, and hens maintained at five per cage suffered a net loss of body weight. In neither experiment was energy utilization affected by crowding since the dietary metabolizable energy values remained constant. In both experiments mucosal maltase and sucrase activities were significantly increased with increasing bird density when birds were fed diets of relatively normal starch content. Plasma-free fatty acids, total fatty acids, and triglyceride levels were not significantly affected by population density, nor were the oleic–linoleic–arachidonic acid levels expressed as percentages of total fatty acids. It would thus appear that lipid metabolism remained relatively normal in hens subjected to overcrowding stress. The levels of peripheral plasma corticosterone and adrenal corticosterone increased in a linear fashion in both experiments with increasing bird density. It would appear that plasma and adrenal corticosterone levels might be useful indices of overcrowding stress in hens.

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