D. Levy

The effect of age and live weight on feed conversion and yield of saleable meat of intact Israeli Friesian male calves

Twelve groups of five Israeli Friesian intact, individually fed, male calves, were slaughtered at different live weights. Commencing with 350 kg, the groups were slaughtered at intervals of 25 kg up to 625 kg live weight. Body and carcass composition data were obtained for each calf, and a feed conversion ratio was calculated. Regression coefficients of age, feed conversion ratio and carcass data on empty body weight, and also the corresponding correlations, were calculated by the equations: y = b + α x for linear and y = bx α for nonlinear regressions. Age increased at a rate very similar to that of empty body weight (α = 1·042). Increase in the amount of feed required to produce unit live weight was much slower (α = 0·045). With increasing empty body weight, dressing percentage and the percentage of kidney, channel and cod fat in the carcass increased moderately (α = 0·011 and 0·004 respectively), the percentage of the external organs decreased moderately (α = −0·010), and the percentage of bone in the carcass decreased very markedly (α = −0·277). The combined effect of these factors was to cause a marked increase in the percentage of saleable meat (α = 0·107) with increasing empty body weight. Results indicate that it is possible to increase the marketing weight of Israeli Friesian male calves considerably without any detrimental effect on carcass composition or economy of production.

Chemical processing of wheat straw and cotton by-products for fattening cattle. 1. Performance of animals receiving the wet material shortly after treatment

Two fibrous roughages, wheat straw and cotton hulls, were treated with 0, 40 and 80 g sodium hydroxide (NaOH)/kg roughage, applied in amounts of water calculated to bring the roughages to moisture contents of 30 and 60%. The effects of these factors on the nutritive values of the two roughages were examined using a 2 × 3 × 2 factorial design. Digestibility trials, in vitro and in vivo , and a 9-mo feeding trial were carried out with the roughages soon after treatment. Concentrates were limited to 6 kg/head per day throughout the animal experiments and roughages were offered ad libitum . Neutral detergent fibre decreased by 7·8 and 13·5% with the 40 and 80 g application rates of NaOH respectively. The treatment of both roughages with NaOH increased considerably their in vitro dry matter digestibility and total solubles after enzyme treatment, the increases being related to the rate of application of NaOH. Digestibility in vivo was improved only by the 40 g NaOH treatment. Treatment with NaOH reduced the voluntary intake of both roughages. Only the 80 g/kg treatment had a positive effect on rate of live- and carcass-weight gain. On the other hand, NaOH improved very significantly the efficiency of conversion of metabolizable energy into live and carcass weight and increased significantly the degree of fatness of the animals. These results indicate a marked improvement in the nutritional value of both roughages due to NaOH treatment. The reason for the small response in rate of gain may be explained by a shortage of protein owing to a possible reduction in its digestibility. Cotton hulls excelled wheat straw in almost every respect. Animals on NaOH-treated cotton hulls bloated chronically unless some long straw was given. Moisture level had practically no effect on performance. The effects of the treatments on rumen or blood constituents were small.

Cottonseed for protein and energy supplementation of high-roughage diets for beef cattle

The use of cottonseed (CS) as an energy and protein supplement to high wheat-straw diets was studied in a digestion and nitrogen balance trial, and as a component in fattening diets in a feeding trial. The proportions of CS studied were 0, 60, 120, 180 and 240 g/kg diet dry matter (DM). DM intake per kg M 0·75 was 33, 31, 40, 31 and 29 g, respectively. The digestibility coefficient of organic matter was 415, 463, 417, 441, 350 g/kg DM and of neutral-detergent fibre was 350, 436, 411, 309, 334 g/kg DM. Nitrogen balance was –2·52, 1·1, 5·38, 5·63, 7·60 g/day respectively, for the same order of treatments. The effect of high proportions of CS in the diet in restricting DM intake and reducing its digestibility was evident. The results of the feeding trial were in agreement with those of the digestion trial and indicate the proportion of 120 g CS per kg DM as optimal and maximal.

The effect of maize grain supplementation of diets based on wheat straw and poultry litter on their utilization by beef cattle

Abstract Six diets were formulated in a factorial design of three poultry litter levels (15, 30 and 45% on a dry matter (DM) basis: low (L), medium (M) and high (H), respectively), and two maize grain levels (0 and 20% on DM basis: − and +, respectively). The rest of the ration in all diets was wheat straw. The in vivo digestibility of DM components, nitrogen balance and digesta mean retention time of these diets were tested on 15 beef intact male calves (initial weight 150 kg). They were allocated (five animals per diet) in individual digestion stalls to diets L−, M−, and H− for a first experimental period, and then to L+, M+ and H+ for a second period, in which each calf had the same poultry litter level as in the first period. Daily DM intake of diets L−, M−, H− was 2.04, 2.19 and 1.79 kg, and of diets L+, M+, H+ was 3.07, 3.37 and 3.16 kg, respectively. The respective digestibility coefficients of organic matter were 50.5, 56.4, 54.3 and 61.3, 61.8, 66.7%, and nitrogen retention was −8.47, −4.04, −9.80 and 8.41, 18.87, 14.21 g day −1 . The replacement of 20% of the diet by maize grain almost doubled the digestible intake (14.8, 17.1, 13.2 MJ day −1 in diets L−, M−, H− and 29.2, 31.0, 30.8 MJ day −1 in diets L+, M+, H+, respectively). The mean retention time of fibres in the gastrointestinal tract and in the rumen was inversely related to the proportion of poultry litter in the diet, while the mean retention time of fluid was not affected.

Effect of dietary protein concentration and source on the growth rate and on body composition of Holstein-Friesian male calves.

Holstein-Friesian male calves, aged 160 to 450 days, and of live weight 180 to 530 kg, were used to determine the effects of dietary nitrogen level and dietary nitrogen source on performance. Experiment 1, tested dietary nitrogen level, and involved two trials with three dietary-nitrogen levels and equal dietary metabolizable energy (ME) 11·7 MJ/kg dry matter (DM). The crude protein (CP) level was reduced in the course of the trials by 40 g/kg, the experimental average CP in the diets being 146, 126 and 106 g/kg for the high (HP), medium (MP) and the low protein (LP) diets, respectively. The urea space (US) for estimation of body protein deposition and the rumen volume for calculation of empty body weight were measured in trial A of experiment 1. Experiment 2 involved four diets of equal ME concentrations; (11-7 MJ/kg DM), in three of which the CP contents were equal but from different sources: (a) 110 g/kg, all of it true protein (TP), negative control; (b) 130 g/kg, all of it TP; (с) 130 g/kg CP, 20 g/kg of it is poultry litter (PL) protein; (d) 130 g/kg CP, 40 g/kg of it is PL protein. Significantly lower US and ratio of US to live weight were found in the calves on the LP diet, from the age of 265 days than in the calves on the other diets. The ratio of US to live weight significantly decreased with increasing age in all protein level treatments. Until the age of 300 days the rumen volume was significantly higher on the LP diet than on the other diets. Calves on the HP diet had the highest daily gain and carcass gain. The recommendation to reduce the dietary protein as age increased to lower than 120 g/kg caused a reduction in the energy retained from the diet but protein deposition was not impaired. Protein deposition was impaired when the CP was reduced by 20 g/kg below the level recommended by the National Research Council. The inclusion of poultry litter in the diet, with ME concentration being maintained, did not reduce the rate of live-weight gain, and improved food conversion efficiency.

Monensin supplementation of young Israeli Friesian male cattle

Four groups of 14 3-month-old Israeli Friesian male cattle were each given monensin supplement in their concentrates at the following rates: between 3 and 6 months of age, 0, 0, 25 and 35 p.p.m.; and between 6 months and slaughter, 0, 35, 35 and 35 p.p.m. They were offered hay at approximately 0·3 % of their live weight and concentrates ad libitum . Daily gain between 3 and 6 months was 1·36, 1·40, 1·50 and 1·57 kg/day, respectively; between 6 months and slaughter it was 1·22, 1·32, 1·33 and 1·24 kg/day, respectively. Differences in intake of concentrates were small. There were no significant differences in slaughter data. Daily carcass gain throughout the experiment was 0·71, 0·74, 0·77 and 0·76 kg/day, respectively. Monensin-supplemented animals were approximately 9% more efficient in the conversion of metabolizable energy into live weight or carcass weight than the control animals. Production of propionate in the rumen was significantly increased in response to monensin supplementation, and the acetate to propionate ratio was significantly reduced.

Ground and pelleted straw and hay for fattening Israeli-Friesian male calves

The performance of Israeli-Friesian male calves on six rations, including two levels (15% and 30%) of ground wheat straw and oatvetch hay in pelleted mixtures, and the same two levels of ground straw in non-pelleted mixtures, was examined. Daily live-weight and carcass gain were higher on the lower level of both roughages. The differences in performance on hay and straw were insignificant. Feed intake was higher on the 15% level of both roughages when pelleted but the energy conversion ratio was higher on pelleted rations of both levels of straw. The dressing percentage was higher for animals on pelleted rations. There was no significant difference in percentage fat trim, percentage bone or percentage saleable meat in the carcasses. There was 20% more kidney, pelvic and cod fat on the lower level of roughage. The digestibility of organic matter was higher on rations with the lower level of roughage, and on the pelleted rations compared with the non-pelleted at equal level of roughage. This was not the case for the digestibility of crude fibre. Nitrogen retention was significantly higher on the lower levels of straw and on the pelleted rations of a similar level, and was higher on hay rations than on straw rations. Ration differences in the molar proportions of volatile fatty acids in the rumen liquor were detected. Pelleting appeared to improve the nutritive value of straw.

Chemical processing of wheat straw and cotton by-products for fattening cattle 3. Performance of animals receiving material in complete feeds

The fibrous roughages, wheat straw (WS) and cotton stalks (CS), were left untreated or treated with 30 g sodium hydroxide per kg, and residual alkali was either neutralized with sulphuric acid or left unneutralized. All roughages were pelleted and used either in complete feeds or separately. The effects of these treatments on the nutritive value of the roughages were examined in digestibility trials in vitro and in vivo , and in a 7·month feeding trial of a factorial arrangement of 2 × 3 × 2, in which the roughages constituted 350 g/kg of the diets. Approximately 150 g/kg of the neutral-detergent fibre (cell wall) constituents of both roughages was solubilized by sodium hydroxide treatment, while the changes in acid-detergent fibre components (cellulose and lignin) were much smaller, although evident. In vitro -dry matter digestibility of wheat straw was 22 % higher than that of cotton stalks, and its increase due to NaOH treatment was 50% and 30% for wheat straw and cotton stalks, respectively. In vivo digestibility of organic matter of wheat straw was increased from 0·47 to 0·59, and that of cotton stalks from 032 to 037. The increase was evident in all components except protein, in which digestibility was reduced. The increase in the metabolizable energy values of wheat straw from 6·86 to 7·45MJ/kg dry matter and that of cotton stalks from 4·77 to 5·10MJ/kg dry matter following sodium hydroxide treatment was not reflected in daily live-weight or carcass-weight gain in the feeding trial. The animals offered NaOH-treated roughages had significantly more fat trim, and more fat in the large depots. Including roughages in complete feeds revealed no advantage in metabolizable energy conversion into live weight.

Soaking of complete fattening rations high in poor roughage 1. The effect of moisture content and spontaneous fermentation on nutritional value

The effect of three moisture concentrations (10, 50 and 75%) and of four fermentation conditions (none, 24 hr aerobic, and 24 and 48 hr anaerobic) on the nutritive value of two complete fattening diets containing 25 and 45% poor roughage, was examined in three digestion and nitrogen balance trials, each of Latin square design, in cattle. Fermentation increased the lactic acid and volatile fatty acid concentrations of the feed, decreased its pH and the crude fibre content, and caused losses of dry matter. There were non-significant differences in voluntary intake between the dry and soaked diets. The apparent digestibility of dry and organic matter, crude protein, nitrogen-free extract and crude fibre was non-significantly improved by added moisture. There were no consistent differences in nitrogen retention. The average metabolizable energy values (ME) observed for both diets were 6% higher than those calculated. There were no significant differences in the apparent digestibility of gross energy or in ME value between treatments of different moisture content. The fluctuations in pH of rumen liquor during the day differed markedly when the animals received different levels of roughage. These differences were greater when the feed was allowed to ferment. Soaking of feed resulted in a significant increase in the concentration of propionic acid in the rumen liquor, and a non-significant decrease in that of acetic acid. Consequently the C 2 /C 3 ratio was significantly lower on the moist feed treatments. There were no consistent differences in concentration of ammonia in the rumen liquor, or of urea in the blood.

Performance of fattening cattle and lactating beef cows on diets high in chemically treated wheat straw and poultry litter

Abstract Three experiments were carried out to study the effect of chemical treatment on the nutritive value of wheat straw (WS) and the effect of diets containing such treated straw and poultry litter (PL) on the performance of fattening cattle and lactating beef cows. The chemical treatment consisted of treating half of the wheat straw with 60 kg sodium hydroxide/t and the other with 60 kg sulphuric acid/t, and then mixing the two to give “Celephos”. The digestibility coefficient of organic matter was 68.0 and 41.7 for “Celephos” and untreated straw, respectively. For a long term feeding trial, two mixtures were formulated: (a) including 23% WS and 19% PL; (b) including 30% chemically treated WS and 16% PL. A conventional high grain fattening diet (c) served as control. The metabolizable energy concentrations in the above diets were 2.37, 2.38 and 2.78 Mcal/kg DM. Protein content of the diets was regulated by PL or soya bean meal. Liveweight gain was 1059, 1137 and 1180 g/day, metabolizable energy conversion ratio to liveweight was 22.8, 20.7 and 20.0 Mcal/kg, and carcass gain was 565, 606 and 656 g/day for treatment groups (a), (b) and (c), respectively. In a third trial, lactating beef cows were fed on long straw or Celephos, PL and 1.5 kg grain per head per day. Intake of Celephos was 28% higher than that of untreated straw and milk output was 3 kg/day higher. This was reflected in an increase of 67 g/day in gain of suckled calves.