摘要:

AbstractTwo experiments in which early‐weaned lambs (4–7 and 5–9 weeks of age) continuously grazed a perennial ryegrass‐white clover sward are described. In both experiments groups of lambs were offered a proprietary concentratead libitum, 2/3 or 1/3 ofad libitumallowance, or no concentrate. Mean daily gains over 56 days in Experiment 1 increased from 88 g without concentrate to 275 g withad libitumconcentrate allowance; the range in daily gains over 71 days in Experiment 2 was 201 g to 253 g respectively. In both experiments mean faecal OM output from herbage decreased as concentrate OM intake in

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01423.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractA non‐protein nitrogen additive containing ammonia, molasses and minerals was applied to precision‐chopped forage maize to raise the crude protein content of the ensiled crop from approximately 8% to 10, 14 or 16%.The dry matter content, total nitrogen, water‐insoluble nitrogen, and water‐soluble nitrogen concentrations were measured at ensiling and 2 and 8 weeks later. The pH and lactic, acetic, propionic and butyric acid contents of the resultant silage were determined 2 and 8 weeks after ensiling.The levels of crude protein achieved were 10.8, 11.5 and 14.2%, which are equivalent to recoveries in the silages of 108, 82 and 89% of the applied nitrogen. After 8 weeks the water‐insoluble nitrogen content of the treated silages had increased while the water‐soluble nitrogen content had decreased. The increase in water‐insoluble nitrogen may have been due to either decreased proteolysis or increased levels of microbial protein.There was a significant increase of 0.6 units in the pH of the silage when comparing the control to the highest rate of additive application. The additive increased the levels of lactic and acetic acid in the

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01424.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractFour groups of ewes grazed swards of red clover (Trifolium pratensecv. Hungaropoly) for 28‐day periods ending 28, 14 or 0 (two groups) days before mating. One of the groups on red clover for the period immediately before mating continued on red clover during mating. At all other times before mating and for 7–8 weeks after mating commenced these ewes were grazed on a predominantly perennial ryegrass‐white clover sward. A fifth (control) group was on the ryegrass sward throughout. There was no apparent adverse effect of red clover on ovulation rate, conception rate or embryo mort

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01425.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractMethods of predicting thein vivodry matter digestibility (DMD) of heather were examined in studies on ten samples of heather which had been fed to sheep in standard digestibility trials. DMD was predicted with similar accuracy from estimates ofin vitrodry matter digestibility (in vitroDMD) and from the concentration of cell‐wall constituents.In vitroDMD was found to be between 10 and 18 percentage units lower than DMD. Freeze drying the samples was the only modification to the technique which both increasedin vitroDMD and the accuracy of the prediction of DMD. Other modifications attempted were the use of different liquor sources, changes in first‐stage incubation time and dilution rate, and nitrogen supplementation of the inocula.The concentration of nitrogen or undigested dietary nitrogen in the faeces could not be used to predict the digestibility of heather with precision. It was concluded that the DMD of a heather diet could be satisfactorily predicted from thein vitroDMD of samples collected from sheep fistulated at the oesopha

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01426.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe initial effect on the underlying sward of spraying bracken with 4.5 kg ha−1a.i. asulam or 2.0 kg ha−1a.i. glyphosate was to cause some damage which was greater if glyphosate was used rather than asulam or if treatment was carried out in August rather than in July.Agrostisspecies were especially susceptible whileFestucaspecies were resistant. The recolonization of areas of bare ground after spraying was primarily byHolcus moliis, Anthoxanthum odoratum, Galium hercynicumandPotentilla erecta, but the population of the latter two species decreased asAgrostisbecame reestablished. IfDigitalis purpurea, Urtica dioicaorCirsium arvensewere present originally, heavy infestations developed following the use of asulam, with a smaller increase after glyphosate spraying. In all cases, by the end of three years after treatment, grasses occupied a greater area of the sward in treated than in control pl

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01427.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThree grass silages made in early June from S23 perennial ryegrass were compared in a 16‐week feeding experiment with twelve Ayrshire cows. The silages were made from uniform herbage which received either formic acid (‘Add‐F’) at the rate of 201 t−1, or a formalin‐sulphuric acid mixture (‘Syiade’) at rates of 2.0 and 4.4 1 t−1. The silages were offeredad libitumeither alone or supplemented with a cube containing 38% CP in the DM at the rate of 1.4 kg per 10 kg milk. The daily intakes of silage DM were not significantly different on the three silage treatments, and averaged 10.7, 11.0 and 11.0 kg per cow on the formic acid and the 2.0 and 44 1 t−1formalin‐acid treatments respectively. The mean daily yields of milk were 15.1, 13.3 and 13.7 kg per cow in the unsupplemented treatments, and 18.2, 18.1 and 18.0 kg per cow in the supplemented treatments on the formic acid and the 2.0 and 44 1 t−1formalin‐acid treatments respectively.On the basis of total animal production expressed in terms of metabolizable energy requirements, it was concluded that the differences between the

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01428.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe intake of maize silage by self‐fed heifers was measured where access to the silage was limited either by reducing the width of the feed face or by restricting the time allowed for feeding. In the first experiment twenty heifers were allowed 0.4 or 0.2 m feed face per head for 7 h daily. In the second experiment fourteen heifers were allowed 0.5 m feed face per head for 5 or 3 h daily. Intake was measured either by estimating faecal output by the chromic oxide technique and then using thein vitroestimate of silage digestibility to calculate individual intakes, or by using the results of eight individually fed heifers to provide a direct relationship between the chromic oxide concentration of the faeces and total intake, and using this to predict the intake of the self‐fed heifers from the concentration of chromic oxide in their faeces. The latter method was found to be the most satisfactory because it took into account the effect of level of feeding on the digestibility of maize silage. Restriction of access to the silage by limiting feed face width (Experiment 1) and time (Experiment 2) significantly reduced intakes by 4 and 7% respectively. In both experiments feeding time was significantly reduced by restriction, but this was partially compensated for by a significant increase in rate of eat

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01429.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractPerennial ryegrass cv. S23 was preserved by fermentation (C), or with the addition of 8.7 1 formalin (35% w/w formaldehyde) per t fresh herbage (F) or of 9.0 1 equal mixture (by vol.) of formalin and formic acid (85% w/w solution) per t fresh herbage (FF). These three silages comprised the treatments in a three‐period, crossover design in which urea (u) was given at the rate of 20 g per kg dietary DM to half the animals. Twelve calves were allocated to the treatment sequences when they were approximately 12 weeks of age from within groups which had previously received diets with or without urea.Calves ate significantly (P<0.001) less of silages F or FF than of silage C when each was offered alone, but when urea was given, intakes of silages F and FF were significantly (P<0.001) increased such that the intakes of all three silages with urea were similar (23.6, 19.6, 19.3, 24.2, 24.2, 24.7 ± 0.51 g DM per kg LW for C, F, FF, Cu, Fu and FFu, respectively). Significantly (P<0.01) more of the DM in silage C was digested than in F or FF and the addition of urea significantly (P<0.05) increased the digestibility of DM from silage FF only (73.8, 71.3, 69.8, 74.6, 70.7, 72.5 ± 0.72% for C, F, FF, Cu, Fu and FFu, respectively). When the silages were given alone, calves spent longer eating and ruminating per kg DM ingested with F or FF than with C. The time spent on F and FF was significantly (P<0.01) reduced by the addition of urea (303, 388, 411, 297, 299, 290 ± 18.9 min per kg DM ingested for C, F, FF, Cu and Fu and FFu, respectively).The results presented suggest that urea partially alleviated the reduction in voluntary intake by calves given herbage preserved using formalin, but the mode of action was not c

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1977.tb01430.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY