Plasma 1,25-dihydroxyvitamin D, insulin-like growth factor-1, calcium, magnesium and phosphorus concentrations in pregnant beef cows and calves from a herd with a known history of congenital joint laxity and dwarfism.

An investigation was undertaken to ascertain the possibility of a relationship between calcium, inorganic phosphorus, magnesium, 1,25-dihydroxyvitamin D [1,25(OH)2D], and insulin-like growth factor-1 (IGF-1) concentrations in blood plasma and occurrence of congenital joint laxity and dwarfism (CJLD) in young cattle. Pregnant cows were fed hay (30 cows) or grass silage (122 cows) during winter months (October 15 to calving in March). Blood samples were taken from cows on seven occasions during the experiment and 48 hours after calving, and from calves at birth, and at seven, 14 and 56 days old. Five per cent of calves born (six of 122) to cows fed grass silage and none born to cows fed hay were affected by CJLD. The diet and health status of calves were not significantly (P greater than 0.05) associated with the plasma concentration of 1,25(OH)2D. The plasma calcium concentration declined with age of the calves (P less than 0.05) but was not affected by the occurrence of CJLD. Plasma phosphorus and magnesium concentrations in calves born to cows fed silage were higher (P less than 0.05) than in those born to cows fed hay. At birth and seven days old, plasma phosphorus concentrations were higher (P less than 0.05) in CJLD-affected calves than in healthy calves but the plasma concentration of IGF-1 was not different (P greater than 0.05). It was concluded that the high plasma phosphorus concentrations in CJLD-affected calves and their dams could be related to the aetiology of the CJLD condition in calves.     

Some effects of feeding pasture silage as a supplement to pasture on reproductive performance in lactating dairy cows

Supplementation of a ryegrass/white clover pasture diet with pasture silage is a common management practice in New Zealand dairy herds. The effect of this supplementation on reproductive performance has not been investigated. Five herds of 20 cows were formed before calving commenced on 1 June 1992. From 5 August to 4 September, two of these herds were fed 5 kg/cow/day of pasture silage in addition to the ryegrass/white clover pasture offered to all herds. Pasture silage supplementation did not alter the intervals from calving to first ovulation, first oestrus, or to conception. However, it reduced the first service conception rate (37.5% v. 53.3%; difference +/- sed = 15.8 +/- 10.0%, for pasture and silage and pasture only cows, respectively). A positive effect on reproductive performance of pasture silage supplementation was not demonstrated in this trial.     

Blood serum tocopherol levels in calves born from cows winter fed hay or grass silage.

Blood serum tocopherol was determined in 44 calves born in the spring from cows that had been fed either timothy grass silage or timothy hay produced in Norther Ontario. On all sampling dates (at birth and at eight, 21, 35 and 60 days of age), calves from the silage group had higher average tocopherol levels than those from the hay group. Studies on serum tocopherol distribution in cows and their calves obtained 60 days after birth from the silage group showed that alpha-tocopherol averaged 85% and beta + gamma-tocopherols 12%. Only trace quantities of delta-tocopherol were detected in the serum of cows but none in those of calves.     

Monitoring of vitamin E status of dry,early and mid‐late lactating organic dairy cows fed conserved roughages during the indoor period and factors influencing forage vitamin E levels

Analysis of blood plasma of 60 cows selected on six Flemish organic dairy farms revealed that on average 12% of all samples and on one farm up to 28% of the organic cows showed plasma vitamin E concentrations less than 3.0 μg/ml, which is considered the minimum level to avoid health risks due to vitamin E shortages. Furthermore, this study showed early lactating and dry cows to be more at risk in relation to animals in mid‐late lactation. In European organic farming, vitamin supplements are only allowed if granted by the local authority to satisfy daily requirements. Therefore, the vitamin E content of the feedstuffs used on the farms was determined. Grass clover silage (GCS) and mixed silage had significantly more vitamin E than hay, maize or grain (p < 0.05) [mean (SD): 52 (35), 29 (20), 4.5 (1.7), 4.9 (4.4) and 7.1 (3.8) mg/kg DM, respectively]. Apparently, variation in the vitamin E content in the silage samples was huge. Hence, the vitamin E content of ryegrass, white and red clover was determined in a second lab scale experiment and the effects of wilting, DM content and supplementation of ensiling additives were investigated. Fresh ryegrass had a higher vitamin E content than white and red clover (p < 0.05) [156 (11.3), 49.3 (0.67) and 74.3 (5.73) μg/g DM, respectively]. These differences remained after the wilting or ensiling. Supplementation of formic acid or lactic acid bacteria at ensiling had no significant effect on the vitamin E content. Overall, it can be concluded that GCS is the most important source of vitamin E in organic dairy farming. A legal possibility for case‐related supplementation should be retained in organic dairy farming as approximately 18% of all dry and early lactating cows were at risk of vitamin E shortage.     

Vitamin E status of healthy Swedish cattle

Using high pressure liquid chromatography the serum concentration of vitamin E was measured in dairy cows fed either hay or silage as their main roughage, in calves fed milk-replacer, and in young intensively fed bulls. The concentrates fed to the cows, calves and bulls were supplemented with 5–10, 25 and 5–10 mg DL-α-tocopheryl acetate per kg, respectively, and the milk-replacer for the calves was supplemented with 50 mg DL-α-tooopheryl acetate per kg powder. Cows fed silage as their main roughage had higher serum vitamin E concentrations (: 3.8–5.2 mg/l) than cows fed only hay (: 2.5–4.1 mg/1). Lactating cows had higher vitamin E concentrations than dry cows (: 4.1–5.2 and 2.5–3.8 mg/l, respectively) and calves and bulls had much lower vitamin E concentrations (: 1.4 and 1.2 mg/l, respectively) than cows. Thirty per cent of the calves and 41 % of the bulls had serum vitamin E concentrations less than 1.0 mg/l, suggesting that in these animals the conventional level of supplementation of feeds with DL-α-tocopheryl acetate in Sweden is probably inadequate for the prevention of nutritional muscular degeneration and other negative effects.     

Effects of stocking rate and corn gluten feed supplementation on performance of young beef cows grazing winter-stockpiled tall fescue-red clover pasture

A winter grazing experiment was conducted to evaluate the effects of stocking rate and corn gluten feed supplementation on forage mass and composition and the BW and BCS of bred 2-yr-old cows grazing stockpiled forage during winter. Two 12.2-ha blocks containing Fawn, endophyte-free, tall fescue and red clover were each divided into 4 pastures of 2.53 or 3.54 ha. Hay was harvested from the pastures in June and August of 2003 and 2004, and N was applied at 50.5 kg/ha at the initiation of stockpiling in August. On October 22, 2003, and October 20, 2004, twenty-four 30-mo-old Angus-Simmental and Angus cows were allotted by BW and BCS to strip-graze for 147 d at 0.84 or 1.19 cow/ha. Eight similar cows were allotted to 2 dry lots and fed tall fescue-red clover hay ad libitum. Corn gluten feed was fed to cows in 2 pastures to maintain a mean BCS of 5 (9-point scale) at each stocking rate and in the dry lots (high supplementation level) or when weather prevented grazing (low supplementation level) in the remaining 2 pastures at each stocking rate. Mean concentrations of CP in yr 1 and 2 and IVDMD in yr 2 were greater (P < 0.10) in hay than stockpiled forage over the winter. At the end of grazing, cows fed hay in dry lots had greater (P < 0.05) BCS in yr 1 and greater (P < 0.10) BW in yr 2 than grazing cows. Grazing cows in the high supplementation treatment had greater (P < 0.10) BW than cows grazing at the low supplementation level in yr 1. Cows in the dry lots were fed 2,565 and 2,158 kg of hay DM/cow. Amounts of corn gluten feed supplemented to cows in yr 1 and 2 were 46 and 60 kg/ cow and did not differ (P = 0.33, yr 1; P = 0.50, yr 2) between cows fed hay or grazing stockpiled forage in either year. Estimated production costs were greater for cows in the dry lots because of hay feeding.     

Forage systems for beef production from conception to slaughter: II. Stocker systems.

Fall weaned Angus calves grazed stockpiled 1) tall fescue (Festuca arundinacea Schreb.), 2) tall fescue-red clover (Trifolium pratense L.), or 3) tall fescue-alfalfa (Medicago sativa L.) or were barn-fed, 4) tall fescue hay, 5) orchardgrass (Dactylis glomerata L.)-alfalfa hay, or 6) tall fescue silage from late October to early April during each of 5 yr. Infection of the fescue with Acremonium coenophialum ranged from 0 to 55%. There were two replications each of steers and heifers for each forage system in a completely random design. Each replicate was grazed by three Angus stockers, except for System 1, which was grazed by six stockers, for a total of 420 stockers. Each pasture replicate contained .8 ha (except System 1, which was 1.6 ha), and the stocking rate was one stocker per .27 ha. Fescue hay and silage were harvested each spring for barn-fed systems from the area stockpiled for grazing by cattle in System 1. Nitrogen fertilizer (90 kg/ha) was applied in early spring and again in early August, before stockpiling; no N was applied to stockpiled fescue grown with legumes. Daily gains by calves grazing stockpiled fescue-alfalfa were greater (P less than .01) than by calves grazing stockpiled fescue-red clover or N-fertilized stockpiled fescue (.50, .33, and .34 kg/d, respectively), but fescue-alfalfa calves required more days (P less than .01) of supplemental hay feeding (105, 60, and 36, respectively). Calves fed fescue hay in the barn gained more (P less than .01) than those fed fescue silage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of Barley or Rape Seed Cake as Supplement to Silage for High-Yielding Organic Dairy Cows

An experiment was carried out to investigate the effects of barley or rape seed cake as supplement to silage given ad libitum on milk production and health of dairy cows. A total of 103 cows were divided into two groups on two farms. Before the experiment, the cows had an average milk yield of 26.9 kg ECM and they were in milk for an average of 99 days. Their average parity was 2.3 and their weight 596 kg. The cows in each group received either solely barley or an isoenergetic mixture of rape cake seed and barley as supplement. The supplement feed was fed frequently by automatic feeding. A mixture of clover grass silage and whole crop silage was fed ad libitum . The daily milk yields were not significantly different in the barley and rape seed cake treatment (22.8 vs 24.1 kg). The milk fat content was not significant different either (4.51% vs 4.35%). However, the protein content tended to be higher in the barley treatment (3.51% vs 3.45%). But the energy corrected milk yield (ECM) was not significantly different in the barley and rape seed cake treatments either (24.2 vs 24.9 kg ECM). No differences in health as indicated by clinical illness treated by the vet and somatic cell count (SCC) was seen. It was concluded that barley and a mixture of isoenergic rape seed cake and barley had similar feeding value when used as supplement with a high proportion of easily digestible clover grass silage allocated ad libitum and frequently allocation of supplementary feed.     

Effect of strategies regarding concentrate supplementation and day-time grazing on N utilization at both field and dairy cow level

N utilization at cow and field level was examined over two grazing periods of 30 days with 64 Holstein dairy cows. At cow and field level the effect of sward type (diploid vs. tetraploid perennial ryegrass, both mixed with white clover) and compressed sward height (6 vs. 10 cm) was examined. At dairy cow level the effect of urea supplementation (0 vs. 145 g/day) and energy supplementation strategy (soy hulls(am)/barley(pm) vs. barley(am)/soy hulls(pm)) was also examined. Cows grazed grass/clover swards for 7.5 h/day and were restrictively fed in the barn (3.2 kg dry matter (DM) in maize silage, 3.6 kg ground barley, 3.6 kg soy hulls per day). In none of the two periods were yield of milk (Period 1: 30.9 kg, Period 2: 25.4 kg), fat, protein and lactose significantly affected by sward type, sward height, urea supplementation or energy supplementation strategy. Urea supplementation increased the urea concentration in milk. Also low sward height and feeding soy hulls(am)/barley(pm) increased the urea concentration, probably due to a higher protein content in the sward and a higher grass intake, respectively. N utilization at cow level was highest with high sward height and no urea supplementation. Feeding soy hulls(am)/barley(pm) increased milk yield numerically but was counterbalanced by an equivalent increase in estimated grass intake, and supplementation strategy seemed therefore not to affect N utilization. At field level the N surplus was higher on diploid than on tetraploid swards (50 and 21 kg N/ha) due to a higher clover content in the diploid swards, whereas the difference in N surplus between sward heights was minimal (32 and 38 kg N/ha). Estimated N removal from the pasture in the grazing periods (intake minus excretion) increased by 5.2 kg N/ha when feeding soy hulls(am)/barley(pm), whereas with no urea supplementation the net N removal increased by only 2.5 kg N/ha. It was concluded that N utilization in dairy cows can be improved by decreasing N intake from both herbage and supplementary concentrate without compromising milk yield, and that N balance at field level could be improved by strategic barn feeding.     

Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 1. In vitro and in vivo studies of nitrogen utilization

Two experiments were carried out to determine the effects of feeding grass silages differing in their water-soluble carbohydrate content, with or without red clover silage, on the efficiency of nutrient use. High-sugar grass, control grass, and red clover were ensiled in laboratory silos for use in an in vitro experiment (Exp. 1). For an in vivo experiment (Exp. 2), the same forage types were baled and ensiled. All silages were well preserved; within experiments the grass silages had similar composition, except for greater (P < 0.05) water-soluble carbohydrate concentrations in the high-sugar than the control grass silage. In Exp. 1, high-sugar grass, control grass, and red clover silages were fed alone or as mixtures (30:70, 50:50, or 70:30 on a DM basis, respectively) of each grass with the red clover silage to a simulated rumen culture system. There were no significant differences in microbial N flow or efficiency of microbial protein synthesis between individual forages. However, the corresponding values for the 70:30 ratio of high-sugar grass:red clover silage were greater (P < 0.05) than for the red clover silage. The value for the efficiency of N use (g of microbial N/g of feed N) was greater (0.86; P < 0.05) for high-sugar grass silage than the control grass silage. In addition, the high-sugar grass:red clover silage mixtures all gave greater (P < 0.05) values for the efficiency of N use than red clover silage alone; this difference was not achieved with the control grass mixture. Experiment 2 was an incomplete Latin square design conducted with 6 Here-ford x Friesian steers (163 +/- 5.9 kg of BW) with rumen and duodenal cannulas fed the following 5 silage diets: high-sugar grass silage; control grass silage; high-sugar grass and red clover silage (50:50 DM basis); control grass and red clover silage (50:50 DM basis); and red clover silage. Rumen NH3-N concentration was lowest (P < 0.05) with the high-sugar grass silage. Microbial N flows to the duodenum and efficiency of microbial protein synthesis were greater (P < 0.05) for steers fed the high-sugar grass silage than for control grass and red clover silages, and mixing red clover with grass silages increased (P < 0.05) these values compared with red clover silage alone. In both experiments, the efficiency of incorporation of silage N into microbial N was more than 20% greater (P < 0.05) for high-sugar grass than for control grass silage. These data suggest that grass silage with high-sugar content provides a forage-based strategy for balancing N and energy supply and improving the efficiency of use of grass silage N in the rumen.     

Productivity and hay requirements of beef cattle in a Midwestern year-round grazing system

Our objective was to evaluate a replicated (n = 2) Midwestern year-round grazing system's hay needs and animal production compared with a replicated (n = 2) conventional (minimal land) system over 3 yr. Because extended grazing systems have decreased hay needs for the beef herd, it was hypothesized that this year-round system would decrease hay needs without penalizing animal production. In the minimal land (ML) system, two replicated 8.1-ha smooth bromegrass-orchardgrass-birdsfoot trefoil (SB-OG-BFT) pastures were rotationally stocked with six mature April-calving cows and calves and harvested as hay for winter feeding in a drylot. After weaning, calves were finished on a high-concentrate diet. Six mature April-calving cows, six mature August-calving cows, and their calves were used in the year-round (YR) grazing system. During the early and late summer, cattle grazed two replicated 8.1-ha SB-OG-BFT pastures by rotational stocking. In mid-summer and winter, April- and August-calving cows grazed two replicated 6.1-ha, endophyte-free tall fescue-red clover (TF-RC) and smooth bromegrass-red clover (SB-RC) pastures, respectively, by strip-stocking. In late autumn, spring-calving cows grazed 6.1-ha corn crop residue fields by strip-stocking. Calves were fed hay with corn gluten feed or corn grain over winter and used as stocker cattle to graze SB-OG-BFT pastures with cows until early August the following summer. First-harvest forage from the TF-RC and SB-RC pastures was harvested as hay. Body condition scores of April-calving cows did not differ between grazing systems, but were lower (P < or = 0.03) than those of August-calving cows from mid-gestation through breeding. Preweaning calf BW gains were 47 kg/ha of perennial pasture (P < 0.01) and 32 kg/cow (P = 0.01) lower in the YR grazing system than in the ML system. Total BW gains ofpreweaning calf and grazing stocker cattle were 12 kg/ha of perennial pasture less (P = 0.07), but 27 kg/cow greater (P = 0.02) in pastures in the YR grazing system than in the ML system. Amounts of hay fed to cows in the ML system were 1,701 kg DM/cow and 896 kg DM/cow-stocker pair greater (P < 0.05) than in the YR grazing system. Extended grazing systems in the Midwest that include grazing of stocker cattle to utilize excess forage growth will decrease stored feed needs, while maintaining growing animal production per cow in April- and August-calving herds.     

Feeding dairy calves and replacement heifers in South-western Sweden: a survey

Daily feed rations, their nutrient contents and live weight gains were recorded for calves and replacement heifers from birth to calving in 122 Swedish dairy herds. Preweaned calves were fed whole milk (45% of the herds), milk replacer alone or milk replacer combined with whole milk. Calf starters were the most frequently used concentrates for preweaned calves, whereas grain dominated for weaned calves and heifers. Grain was supplemented with protein concentrates until 6 months of age and at calving. Grass/clover hay was the dominant forage for preweaned calves, whereas grass/clover silage alone or in combination with hay was the most common forage for calves and replacement heifers from 6 months of age. Heifers grazed semi-natural grasslands, leys or a combination of semi-natural grasslands and leys in 33, 15 and 52% of the herds, respectively. According to Swedish recommendations, calves in a majority of the herds were fed too low concentrations of crude protein from weaning to 6 months of age and calves were fed too low a metabolizable energy content inadequate for a daily weight gain of 700 g at weaning. Median live weight gain from birth to calving was only 567 g per day. Correct feed ration formulations and strategic grazing management could be means to increase weight gain and hence to decrease rearing costs of calves and replacement heifers in Swedish dairy herds.     

Effects of feeding frequency on the performance and welfare of mature Hereford cows and their progeny

A study was conducted to assess the effects of daily feeding (D) vs. feeding every third day (3D) on the performance of suckler cows and calves. In treatment 3D, the cows received the entire three-day feed portion on the first feeding day. The feeding regimens were imposed during the indoor feeding period in cold circumstances with grass silage and hay offered in the proportions of 1 : 1 on an energy basis for the cows. Thirty-two mature Hereford cows with an initial live weight (LW) of 787 kg and body condition score (BCS) of 3.33 were selected for the experiment. The experiment consisted of a winter feeding period and a grazing period averaging 225 and 96 days, respectively. Indoors the cows received a daily average 94 MJ metabolizable energy. The in vivo digestibility of dietary organic matter was similar in both treatments. No significant differences between the treatments were observed in cow LW, BCS, milk production and calf LW. Thirty-one cows were observed to be pregnant after the mating period. In the 3D treatment the serum concentrations of urea and long-chain fatty acids were increased on the third day after feeding compared to first and second days throughout the experiment, possibly due to activation of lipolysis and proteolysis. The 3D cows spent on average more (P < 0.001, 9.1% vs. 4.5%) time lying and less time (P < 0.05, 32.9% vs. 40.1%) outdoors than the D cows. On the basis of the results, feeding every third day is an acceptable winter feeding strategy for mature suckler cows if the cows receive enough energy for maintenance and milk production.     

Indigestion in Young Calves. V. The Influence of Grass Silage and Fine Hay

In an experiment with 24 young calves, lasting 45 days, all were fed a high lactose milk replacer causing some diarrhoea. Eight calves received grass silage and 8 fine hay in addition, while 8 received no solid supplement to the milk replacer (NS). Somewhat more (P < 0.05) dry matter was ingested from silage than hay. Weight gain was similar on the 2 supplements and much greater (P < 0.001) than on NS. Both silage and fine hay reduced (P < 0.01) the frequency of diarrhoea, approximately to the same extent. Further, silage or hay gave higher pH (P = 6.0.01 and 0.02, respectively) and less gram positive cocci and rods in the rumen fluid, better developed ruminai papillae and heavier (P < 0.01) empty reticulo-rumens than NS. Some calves fed silage had ulcers in the rumen, the same having occurred on fine hay in earlier experiments, but not in the present one. Althogether, the 2 roughages gave very similar results.     

Effect of fiber-based creep feed on intake, digestion, ruminal fermentation, and microbial efficiency in nursing calves

Six Angus crossbred cow-calf pairs (653 +/- 35 kg and 157 +/- 10 kg initial BW for cows and calves, respectively) were used to evaluate the influence of a fiber-based creep feed on intake, ruminal fermentation, digestion characteristics, and microbial efficiency in nursing beef calves. Cow-calf pairs were stratified by calf age and assigned randomly to one of two treatments: control (no supplement) or supplemented. Supplemented calves received 0.9 kg of a 49% soy hulls, 44% wheat middlings, 6% molasses, and 1% limestone supplement (DM basis) daily. All calves were cannulated in the rumen and duodenum and given ad libitum access to chopped brome hay (Bromus inermus L; 7.43% CP, 40.96% ADF, and 63.99% NDF; DM basis). Supplementation was initiated on May 1 (88 +/- 10.3 d calf age). Three sampling periods were conducted throughout the study (June 14 to 25, July 5 to 16, and August 9 to 20). Supplement and forage were offered at 0800 daily. Total, hay, and milk OM intakes of nursing calves were not affected by supplementation (2,014 vs. 2,328 +/- 288.8, 1,486 vs. 1,029 +/- 3,06.9, and 528 vs. 575 +/- 87.0 g/d, respectively). Milk OM intake was less (P < 0.09) in August than in June and July (635, 691, and 345 +/- 110.6 g/d for June, July, and August, respectively). A supplementation x month interaction occurred (P < 0.10) for total-tract OM digestion. Supplementation did not affect (P > 0.40) total-tract OM digestibility during June and August; however, during July, total-tract OM digestibility was lower (P = 0.03) for the control calves. Ruminal ammonia concentration, total VFA, and butyrate molar proportion increased (P < 0.05), whereas acetate proportion decreased (P = 0.01) in supplemented calves. Microbial efficiency was not influenced by supplementation (11.8 vs. 12.0 g/kg of OM truly fermented for control and supplemented calves, respectively). These data indicate that fiber-based supplements can be used as creep feed without negative effects on OM intake, total-tract OM digestibility, and ruminal fermentation characteristics in nursing beef calves.     

Effects of feeding and animal performance on nitrogen, phosphorus and potassium excretion by Holstein cows

Thirty‐four Holstein dry cows and 16 lactating cows were used in balance trials to identify the effects of feeding and animal performance on nitrogen (N), phosphorus (P) and potassium (K) excretion by dairy cows, and to develop prediction models for these excreta. Orchard grass silage, corn silage, alfalfa silage or timothy hay were offered to dry cows. Orchard grass silage or alfalfa silage, and concentrates were offered to lactating cows. In the statistical analysis, the independent variables were bodyweight (kg), dry matter (DM) intake (kg/day), milk yield (for lactating cows only, kg/day), water intake (free water plus water in feed, kg/day), intake (g/day) of N, P and K and dietary contents (% of DM) of crude protein, P and K. The dependent variables were N, P and K excretion (g/day) in feces and urine. In both dry and lactating cows, intake of N, P and K had large effects on corresponding excretion. The results indicated that a decrease in the intake of N, P and K could decrease the corresponding excretion. Further research by path analysis showed that K intake positively affected urinary N excretion in dry cows indirectly, through water intake and urine volume.     

Ultrasonography of the reticulum, rumen, omasum and abomasum before, during and after ingestion of hay and grass silage in 10 calves

The reticulum, rumen, omasum and abomasum were assessed via ultrasonography in 10 healthy female calves before, during and 2h after feeding hay and grass silage. The evaluations were made using an ultrasound machine with a 5.0MHz linear transducer. The reticulum could be visualized before feeding in all the calves. Its appearance and pattern of contractions were similar to those in adult cattle, although the amplitude (5.2±1.06cm) and velocity (3.5±1.42cm/s) of the first contraction were markedly less than in adult cattle. The position and size of the entire rumen including the dorsal and ventral sacs and the ruminal contents were assessed. Except for its smaller size, the ultrasonographic appearance of the omasum of calves was similar to that of adult cattle. The abomasum was seen to the left and right of the ventral midline before feeding in all calves; it occupied considerably more space on the left than the right. Compared with its appearance before feeding, the ultrasonographic appearance of the rumen, omasum and abomasum did not change during or after feeding. Ultrasonography is an ideal imaging tool for evaluating the reticulum, rumen, omasum and abomasum before, during and after feeding in calves.     

Diagnosis of copper deficiency and effects of supplementation in beef cows.

The effects of feeding supplementary dietary copper to a herd of 400 beef cows, were studied over a two year period. In the first year of the trial, the calves showed clinical signs of copper deficiency. There was improved growth following subcutaneous injection of copper ethylenediamine tetraacetate, and the treated calves had a 2.8% increase in adjusted weaning weights. In the second year of the trial pregnant cows were fed a basal ration of bromegrass silage, barley and minerals over the winter feeding period. The feed was supplemented with copper so that half received 5.5 mg/kg of copper on a dry matter basis and half 40 mg/kg. Calving occurred in the spring and half the calves were treated with injectable copper at birth and again at 12 weeks of age. There was no evidence of copper deficiency in the calves and there was no effect of high level copper supplementation on calf birth weight, or neutrophil candidacidal activity. Susceptibility to diarrhea varied in a complex fashion; morbidity was lowest in calves born to dams fed supplementary copper and highest in calves born to supplemented dams and injected with copper at birth. The cows and calves grazed the same copper deficient pasture over the summer. The average daily gain for calves born to supplemented cows was 0.999 +/- 0.010 kg/day (x +/- SEM) which was significantly greater than the 0.972 +/- 0.009 kg/day for calves from nonsupplemented dams (p = 0.044). The benefit of copper supplementation on 200 day weaning weight was estimated at 4.8 kg. Evidence of copper deficiency was seen when a herd test showed mean serum levels below 9 mumol/L and liver values below 0.09 mmol/kg wet matter.     

Composition and Nutrient Deficiencies of Arkansas Forages for Beef Cattle

A database was compiled to determine the nutrient composition, variability, and nutrient deficiencies of 11,592 forage samples (10,246 hay, 1,001 pasture, and 345 silage) collected from 1985 to 1999. Samples were analyzed for 1 to 15 nutrients: DM, N, ADF, NDF, P, K, Ca, Mg, Na, S, Fe, Mn, Zn, Cu, and Se. Mean (±SD) CP and TDN levels (% DM) of bermudagrass, fescue, and mixed grass (blends of bermudagrass, fescue, orchardgrass, ryegrass, and cheat) hays were 12.4 ± 3.5, 60.0± 6.2; 11.2± 3.0, 53.8± 4.7; and 11.1 ± 3.1, 52.9± 4.7, respectively. For beef cows and calves, TDN was deficient in a greater percentage of hays (P < 0.05) than was CP. Bermudagrass hays contained greater levels of CP and TDN than fescue or mixed grass hays (P < 0.05). Fescue and mixed grass hays did not differ (P > 0.05) in CP, ADF, NDF, or TDN concentrations. Only 6 to 10% of the hays analyzed for Na contained adequate levels for beef cows and calves. Selenium, Cu, and Zn were deficient in 62, 52, and 41% of the hay samples, respectively. For lactating beef cows, a lesser percentage of the hays were deficient in P (16%), Ca (7%), Mg (30%), and S (8%). Iron, Mn, and K were deficient in 2% or less of the hays. Bermudagrass, corn, and sorghum-sudan silages contained greater (P < 0.05) levels of TDN than silages composed of fescue, mixed grass, ryegrass, sorghum silage types, or wheat. With the exception of bluestems and orchardgrass, the pasture samples contained greater concentrations of CP and TDN than the same forage species harvested as hay. In general, forages were highly variable in nutrient content, and most hays were deficient in one or more nutrients for beef cattle.     

Evaluation of berseem clover in diets of ruminants consuming corn crop residues

Berseem clover hay was compared to alfalfa hay provided at 0, 25, and 50% of the diet DM in mixtures with corn crop residues to wether lambs. Berseem clover hay had lower (P < .05) concentrations of NDF, ADF, and CP than alfalfa hay. The digestibility of DM, DMI, and N balance did not differ (P > .05) between diets containing alfalfa hay or berseem clover hay. To evaluate stockpiled berseem clover as a supplement for grazed corn crop residues, berseem clover and oats were incorporated into a corn-corn-oat/berseem clover crop rotation for 3 yr in replicated 6.1-ha fields. Two cuttings of oat-berseem clover hay were harvested each summer before forage was stockpiled for winter grazing. After corn grain harvest, multiparous and primiparous crossbred cows in midgestation were allotted to each field at 1.01 ha/cow to strip-graze corn crop residues with or without stockpiled berseem clover or allocated to replicated drylots for 98 to 140 d. Each group was offered alfalfa-grass hay as large bales to maintain a mean body condition score of 5 on a 9-point scale. Mean rates of total and digestible OM disappearance from grazed and ungrazed field areas of berseem clover and corn crop residues did not differ over the 3 yr. In vitro organic matter disappearance (IVOMD) tended to decrease more rapidly (P = .13) and NDF and ADF concentrations increased more rapidly (P < .05) in berseem clover than in corn crop residues. Seasonal BW change did not differ (P > .05) between winter management systems in any year, and seasonal body condition score changes did not differ (P > .05) between cows grazing corn crop residues and berseem clover and those maintained in a drylot in yr 2 and 3. Cows grazing corn crop residues with or without berseem clover required less (P < .05) hay than those maintained in drylot. Although the effects of berseem clover hay supplementation on the intake and digestibility of corn crop residues do not differ from alfalfa hay, the nutritional value of stockpiled berseem clover decreases rapidly during winter, limiting its value as a standing supplement for corn crop residues in late winter.