Three studies were conducted to evaluate: 1) rotationally grazed forage for late-summer stockpiling; 2) effects of lactation on self-fed supplement intake; and 3) influence of cow age on hand-fed supplement intake. For the first study, treatments consisted of non grazed, 2X and 3X grazed. Crude protein of forage grazed 3X was greater (P<.10) than non-grazed. Yield of non-grazed forage was greater (P<.10) than forage grazed 2X and 3X. Non-grazed forage displayed the greatest stockpiled yield and grazing influenced quality of stockpiled forage to a small magnitude. Treatments for the second study consisted of non, mid, and late-lactation on two experimental diets. Late-lactation cow BW change was less (P<.10) than non-lactating in both experiments and less (P<.10) than mid-lactating cows in Exp. 1 only. Forage intake for late-lactating cows was less (P<.10) than mid-lactating cows in Exp. 1 and tended to be greater (P=.13) than non-lactating cows in Exp. 2. Self-fed supplement intake was highly variable but not influenced by lactation. Treatments for the third study consisted of five age groups. In yr 1, weight change at d 57 for 11-yr cows was greater (P<.10) than 5-yr cows. In yr 2, weight change at d 28 for 8-yr cows was less (P<.10) than 4, 6, and 10-yr cows and 4-yr cows was greater (P<.10) than 6, 10, and 12-yr cows. At d 56, weight change for 4-yr cows was greater (P<.10) than 6, 8, 10 and 12-yr cows and 12-yr cows was less (P<.10) than 6 and 10-yr cows. Weight change at calving for 4-yr cows was greater (P<.10) than 6, 8, and 12-yr cows. Forage intake of 10-yr cows was greater (P<.10) than 8 and 4-yr cows. Supplement intake of 4-yr cows was greater (P>.10) than 8, 10, and 12-yr cows. Six-yr cows had greater (P<.10) supplement intakes than 12 and 8-yr cows. Three and 4-yr cows displayed the best performance and 4-yr cows consumed the greatest amount of supplement. / Graduation date: 2000

Three experiments were conducted to evaluate the influence of quality of supplemental alfalfa quality on beef cattle consuming low-quality meadow grass (MG) roughages. Fifteen steers (250 kg) were assigned randomly to one of three treatments: 1) meadow grass (5.2% CP), no supplement (MNS); 2) meadow grass plus high quality alfalfa hay (AHS) (18.8% CP); and 3) meadow grass plus low quality alfalfa hay (ALS) (15.2% CP). Supplements were fed at 0.45% BW and 0.55 % BW respectively. Total DM intake was greater (P<.01) for alfalfa supplemented steers. Likewise intake of digestible DM, DM digestibility and ruminal ammonia levels were greater for alfalfa supplemented steers (P<.01). In Exp. 2; 96 gestating Hereford x Simmental cows (537 kg; body condition 4.86) were assigned to the same treatments as in Exp. 1. For d-0 to d-42 cows grazed on 19.1 ha of stockpiled MG (4539 kg/ha; 6.8% CP) whereas d-43 to d-84, cows received MG hay (5.2% CP). Results for the 84-d study indicated that supplemented cows gained more BW (P<.01), body condition (P<.01) and had heavier (P<.01) calf birth weights than MNS cows. In the first 42-d period supplemented cows gained 16.2 kg more BW than MNS cows (P<.01). Likewise, supplemented cows increased .24 BC more (P<.01) than MNS cows. The same trend was observed from d-42 to d-84, though ALS cows lost more BC (P<.01) than the AHS cows. In Exp. 3; 90 gestating Angus x Hereford cows (475 kg; body condition 4.59) were assigned to one of three supplemental treatments: 1) 16.1% CP alfalfa; 2) 17.8% CP alfalfa; 3) 20.0% CP alfalfa. The level of supplementation was 0.63%, 0.55%, and 0.50% of BW, respectively. The basal diet was baled MG hay (5.6% CP). Weight gain and BC change for the 84-d study displayed a quadratic response (P<.10). In conclusion, alfalfa hay is an effective way of increasing low-quality roughage DM intake and digestibility. However, alfalfa hay quality did not appear to dramatically effect BW, BC, and (or) calf birth weights, when fed on a isonitrogenous basis. (KEY WORDS: Beef cattle, Supplementation, Meadow Hay, Alfalfa Hay) / Graduation date: 1997

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Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 61-66). / vii, 66 leaves, bound ill. 29 cm

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Ten attributes representing various body and. carcass measurements of beef steers were considered for statistical analysis. The slaughter data were obtained from an experiment conducted at Blacksburg, Virginia, by members of the Animal Science Department of the Virginia Polytechnic Institute, described by Kelly et al. (1968). The objective of the study was to obtain estimates of the effects of slaughter time (age), and of the energy level of the ration fed, on the body proportions and carcass composition of beef steers from approximately 7 to 30 months of age. The nutritional regimens used were: Ration I - maintenance; Ration II - full feed of hay; Ration III - limited concentrate plus full feed of hay; Ration IV - full feed of a fattening ration. According to the design of the experiment, the linear model included the general mean, the effects of slaughter time, breed, trial, slaughter time by trial interaction and slaughter time by breed interaction, and an error term. The first part of the investigation dealt with the analysis of variance of the percentage hot carcass to determine whether the effects of breed and trial were significant. In the second part, only the general mean, the slaughter time effect, and an error term were included in the model. When the slaughter time was found significant or highly significant, the sum of squares due to slaughter time was divided into regression components to determine which polynomial regression model best described the relationship between the body component mean and age. The results of the statistical analyses were as follows: 1. Breed and trial effects on the percentage hot carcass were insignificant in all but ration II, in which trial was significant. 2. Slaughter time by trial interaction effect was significant in all rations; slaughter time by breed was not. 3. The percentage hot carcass behaved in a parabolic manner with age, which was concave upward at lower planes of nutrition; the pattern changed to cubic at higher planes. 4. Age had no effect on the mean empty-body weight with steers on ration I; the effect was linear on ration II; quadratic on rations III and IV. Similar growth pattern was obtained for the percentage meat. 5. The percentage of front quarter to total carcass increased proportionately with age in all rations; the opposite trend was obtained for the percentage hind quarter. 6. The relationship of weight of the head, expressed as percentage of the live weight, with respect to age or slaughter time was linear with positive slope on rations I and II and negative on rations III and IV. 7. The percentage moisture in the meat showed a quartic regression with age on ration I presumably due to random fluctuation of the means. For rations II and III, the relationship was quadratic and concave downward; for ration IV, it was linear with negative slope. 8. The percentage crude protein and the percentage ash behaved similar to that of the percentage head, while opposite pattern was obtained for the ether extract. / Ph. D.

We conducted two experiments evaluating perennial ryegrass straw as a forage source for ruminants. Experiment 1 evaluated digestion and physiological variables in steers offered perennial ryegrass straw containing increasing levels of lolitrem B. Sixteen ruminally cannulated Angus X Hereford steers (231 ± 2 kg BW) were blocked by weight and assigned randomly to one of four treatments (TRT). Steers were provided perennial ryegrass straw at 120% of the previous 5-d average intake. Prior to straw feeding, soybean meal (SBM) was provided (0.1% BW; CP basis) to meet the estimated requirement for degradable intake protein. Low (L) and high (H) lolitrem B straws (<100 and 1550 ppb, respectively) were used to formulate TRT diets: LOW (100% L); LOW MIX (67% L:33% H); HIGH MIX (33% L:67% H); HIGH (100% H). Intake and digestibility of DM and OM, and ruminal pH, total VFA, and NH₃-N were not affected by increasing lolitrem B concentration (P>0.13). Ruminal indigestible ADF (IADF) fill increased linearly (P=0.01) and IADF passage rate (%/h) decreased linearly (P=0.04) as lolitrem B level increased. Experiment 2 evaluated performance and production of 72 Angus X Hereford cows (539 ± 5 kg BW) consuming perennial ryegrass straw containing increasing levels of lolitrem B during the last third of gestation. Cows were blocked by body condition score (BCS) and randomly assigned to one of three TRT. Cows were provided perennial ryegrass straw ad libitum and supplemented with SBM (0.1% BW; CP basis) to meet the estimated requirement for degradable intake protein. Mixtures of a L and H lolitrem B straw (467 and 2017 ppb, respectively) were used to formulate TRT diets: LOW (100% L); MIX (50% L:50% H); HIGH (100% H). Thirteen of 24 cows on the HIGH TRT exhibited signs of ryegrass staggers and were removed from the study. Dry matter intake was not affected (P>0.12) by increasing lolitrem B concentration; however, estimated DM digestibility decreased linearly (P<0.01) as lolitrem B concentration increased. Lolitrem B concentration did not influence pre- or post calving weight or BCS change (P>0.10). These data suggest that feeding perennial ryegrass straw containing up to 1550 ppb lolitrem B does not adversely affect nutrient digestion or physiological response variables in steers. However, providing straw with a lolitrem B concentration of approximately 2000 ppb resulted in 54% of cows exhibiting signs of ryegrass staggers. Blending of H and L straws appears to be a successful management practice. Keywords: Alkaloid, Beef Cattle, Endophyte, Lolitrem B, Perennial Ryegrass, Straw / Graduation date: 2004