Biomedical subjects

M B Judkins

Publications and source records attributed to M B Judkins.

26 records · Page 2Linked to original sources

PubMed1991

Metabolizable energy for maintenance of beef-type Bos taurus and Bos indicus x Bos taurus cows in a dry, temperate climate.

Metabolizable energy for maintenance (MEm) was estimated using 123 mature cows of eight diverse breed groups. Cows in each breed group were allotted at random 1) to limit-feeding to approximate maintenance or 2) to ad libitum access to feed. The MEm values were calculated by regression of change in body energy on ME intake. The MEm values for mature Hereford, Red Poll, Hereford x Red Poll, Red Poll x Hereford, Angus x Hereford, Angus x Charolais, Brahman x Hereford, and Brahman x Angus breed types were as follows: 145, 169, 148, 149, 144, 152, 139, and 143 kcal.kg-.75.d-1, respectively. Bos indicus-cross cows ranked lowest for MEm/kg.75. Angus x Hereford cows averaged highest in terms of grams of calf weaned per mature female exposed divided by yearly MEm requirement. Hereford x Red Poll reciprocal crosses on average required 640 kcal less total daily MEm per animal than Hereford and Red Poll straightbreds.

Adipose Tissue↗

PubMed1991

Effects of cottonseed meal supplementation time on ruminal fermentation and forage intake by Holstein steers fed fescue hay.

Four ruminally cannulated Holstein steers (average BW 303 kg) were used in a 4 x 4 Latin square design digestion trial to study the influence of daily cottonseed meal (CSM; 1.6 g of CP/kg of BW) supplementation time on forage intake and ruminal fluid kinetics and fermentation. Steers were housed individually in tie stalls and were fed chopped fescue hay on an ad libitum basis at 0600 and 1400. Treatments were 1) control, grass hay only (CON) and grass hay and CSM fed once daily at 2) 0600 (EAM) 3) 1000 (MAM), or 4) 1400 (PM). Ruminal NH3 N concentrations reflected a time of supplementation x sampling time interaction (P less than .05); CON steers had the lowest (P less than .05) ruminal NH3 N concentrations at all times other than at 0600, 1000, 1200, and 2400, when they did not differ (P greater than .05) from at least one of the supplemented groups. Forage intake, ratio of bacterial purine:N, rate of DM and NDF disappearance, and ruminal fluid kinetics were not influenced (P greater than .05) by supplementation time. Total ruminal VFA differed (P less than .05) between CON and supplemented steers, as well as among supplemented steers (linear and quadratic effects P less than .05). Acetate, propionate, and valerate proportions were influenced (P less than .05) by a sampling time X supplementation time interaction. Under the conditions of this study, greater peak ammonia concentrations with morning supplementation than with afternoon supplementation did not stimulate ruminal fermentation or rate of NDF disappearance.

Ammonia↗

PubMed1990

Digesta kinetics, ruminal fermentation characteristics and serum metabolites of pregnant and lactating ewes fed chopped alfalfa hay.

Eight ruminally cannulated ewes (four control and four bred; average BW = 85.7 kg), limit-fed alfalfa hay (1.86% BW), were used in two experiments to determine the effects of pregnancy and lactation on digestive function and serum metabolites. Seven-day sampling periods were used starting on d 102, 118 and 132 of gestation (Exp. 1) and d 14 and 32 of lactation (Exp. 2). Particulate (6.8 vs 4.9%/h; PPR) and fluid passage rates (13.9 vs 10.9%/h) were greater (P less than .05) and gastrointestinal mean retention time (28.9 vs 35.7 h) and fluid turnover time (FTT, 7.5 vs 9.5 h) were lesser (P less than .05) in pregnant than in nonpregnant ewes, respectively. Isobutyrate concentration was lower (P less than .05) in pregnant (1.7 mol/100 mol) than in nonpregnant (1.9 mol/100 mol) ewes. No differences (P greater than .10) were noted for any other ruminal fermentation measures between pregnant and nonpregnant ewes. In Exp. 2, no differences (P greater than .10) were noted in digesta kinetics or ruminal fermentation measures except for isobutyrate and isovalerate molar proportions and serum urea N (SUN) concentration. Isobutyrate, isovalerate and SUN concentrations (21.8 vs 26.1 mg/dl) were lower (P less than .05) in lactating ewes than in nonlactating ewes. Gastrointestinal fill (5.7 vs 7.7 g/kg BW) and FTT (9.3 vs 12.7 h) were lesser and DM digestion (66.7 vs 57.4%) was greater (P less than .05) in lactating than in nonlactating ewes. Data suggest that, during pregnancy, passage rate increases occur without affecting DM digestion and that, during lactation, PPR is not affected when ewes are limit-fed.

Animals↗

PubMed1990

Luteinizing hormone in nutrient-restricted ovariectomized ewes.

This study was designed to evaluate profiles of serum concentrations of LH, pituitary content of LH and GnRH receptors, and hypothalamic content of GnRH in undernourished, ovariectomized ewes. In earlier studies, pulsatile secretion of LH diminished as duration of undernutrition progressed in prepubertal or adult ovariectomized ewes. Ewes having similar body condition scores (CS) of 5 to 9 (1 = extremely thin, 5 = moderate, 9 = obese) were fed maintenance or low-energy diets (100% and 60% of NRC requirements, respectively). Blood samples for analysis of LH were collected at 15-min intervals for 4 h at initiation of the project and immediately prior to slaughter. Serum concentrations of LH did not differ (P greater than .05) among groups at the initial sampling period. At slaughter, ewes with CS less than or equal to 2 (n = 7) had lost 26.8 kg (42% of initial weight). Ewes with CS greater than or equal to 3 (n = 12) had lost an average of 13.7 kg (18% of initial weight). Concentrations of LH in ewes with final CS greater than or equal to 3 was similar (P greater than .05) to that observed during the initial sampling period. However, release of LH was reduced (P less than .01) in ewes with CS less than or equal to 2 compared with ewes with CS greater than or equal to 3 (2.6 vs 9.5 and 3.2 vs 10.5 ng/ml for basal and mean concentrations, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Estimating diet digestibility: a comparison of 11 techniques across six different diets fed to rams.

Six digestion trials were conducted using eight Suffolk rams (four/trial; two trials run concurrently) to determine the ability of 11 techniques to estimate in vivo apparent DM digestibility (DMD). Diets (trials) were as follows: 1) ad libitum access to chopped fescue hay, 2) ad libitum access to alfalfa hay, 3) limit-fed fescue hay, 4) limit-fed alfalfa hay, 5) 25% soybean meal and 75% fescue hay and 6) 40% rolled corn and 60% alfalfa hay. Total feces were collected for 7 d following a 21-d adaptation to each diet. Digestibility methods evaluated were the following: 1) in vitro disappearance (INVITRO); 2) 48 h and 3) 72 h in situ nylon bag (48NB, 72NB); 4) 48NB followed by a 48-h acid pepsin digestion; 5) 96 h and 6) 144 h in vitro fermentation followed by NDF analysis (INDF96 and INDF144) 7) 96 h and 8) 144 h in vitro fermentation followed by ADF analysis (IADF96 and IADF144); 9) ADL ratio; 10) alkaline hydrogen peroxide treatment before ADL analysis (APFPRE) and 11) alkaline hydrogen peroxide treatment after ADF extraction of ADL (ADLPST). Apparent in vivo DMD was accurately estimated (P greater than .10) by INVITRO, ADL and APLPST with Diet 1. However no marker accurately estimated in vivo DMD when fescue was limit-fed. Apparent DMD of Diet 2 was accurately predicted (P greater than .10) by INVITRO, but when Diet 2 was limit-fed, only 48NB and 72NB predicted (P greater than .10) DMD accurately. In vivo DMD coefficients for Diet 5 followed a pattern similar to that of Diet 1. Diet 6 was predicted by INVITRO, 48NB, INDF96, INDF144 and IADF96 (P greater than .10). Results suggest that caution should be exercised when using these techniques, because no single technique provided accurate estimates across all diets and feeding conditions.

Analysis of Variance↗

PubMed1990

Influence of branched-chain fatty acid supplementation on voluntary intake, site and extent of digestion, ruminal fermentation, digesta kinetics and microbial protein synthesis in beef heifers consuming grass hay.

Four heifers (British x British; average BW 372 kg) cannulated at the rumen and duodenum and consuming a grass hay (fescue-orchardgrass) diet were used in a 4 x 4 Latin square and supplemented with four levels (0, 20, 40, and 60 g.head-1.d-1) of supplemental four- and five-carbon VFA (BCFA). Forage OM, ADF, NDF and N intakes and digestibilities were not affected (P greater than .10) by BCFA supplementation. Likewise, duodenal N (microbial, feed and ammonia) flows and microbial efficiency were not altered (P greater than .10) by BCFA supplementation. Neither particulate and fluid passage rate nor in situ rate of NDF digestion was affected (P greater than .10) by treatment. Ruminal pH, ammonia concentrations and total VFA concentrations were similar (P greater than .10) among treatments. Ruminal proportions of acetate and propionate were not affected (P greater than .10) by treatment; however, butyrate responded in a cubic (P less than .05) fashion to BCFA, with the lowest proportion of butyrate at the 40 g BCFA feeding level. A time x treatment interaction (P less than .05) was noted for isobutyrate, isovalerate and valerate proportions; they were increased as a function of BCFA dosage at 2 to 8 h postdosing. Supplemental four- and five-carbon VFA had no effect on digestion and fermentation of grass hay. Supplementation of low-quality roughages with BCFA is not justified.

Ammonia↗

PubMed1990

Thirty or sixty percent milk replacer reduction for calves: effects on alfalfa hay intake and digestibility, digestive kinetics and ruminal fermentation.

Twelve artificially reared, male Holstein calves, ruminally cannulated at 53 d of age, were used in a split-plot design to study the effects of no milk replacer reduction (CON), or reduction by 30% (30R) or 60% (60R) of this value on alfalfa hay intake and digestibility, ruminal fermentation and digestive kinetics. Milk replacer reduction began at 53 d of age and continued until 135 d of age, after which no milk replacer was fed. All calves had ad libitum access to long-stemmed alfalfa hay from birth. Five collection periods were conducted at average calf ages of 72, 87, 108, 129 and 151 d. Reducing the amount of milk replacer fed resulted in a linear increase (P less than .05) in forage OM intake; however, total OM intake (forage + milk) was not different (P greater than .10) among milk reduction groups. Size of particles in feces exhibited quadratic effects in response to milk replacer reduction (P less than .05) but only in the small (less than 150 microns) size groupings. Ruminal pH and ammonia and individual VFA concentrations (except isobutyrate) were not altered by milk reduction (P greater than .10) but increased (P less than .01) with calf age. Milk replacer reduction had a quadratic effect (P less than .05) on fluid outflow rate from the rumen, increasing as milk replacer was reduced. Other fluid and particulate kinetic data, as well as NDF digestion rate and DM digestion showed no effects (P greater than .10) from milk replacer reduction but changed with calf age. Milk replacer reduction increased forage intake but had minimal effects on digestive variables evaluated, suggesting that intake of milk replacer by calves can be reduced by up to 60% without disturbing forage fermentation and passage.

Age Factors↗

PubMed1988

Influence of two levels of enzyme preparation on ruminal fermentation, particulate and fluid passage and cell wall digestion in wether lambs consuming either a 10% or 25% grain diet.

Effects of a fungal enzyme preparation on ruminal fermentation, digesta kinetics and cell wall digestion were studied. Either 0, 22 or 25 g/d of enzyme preparation was offered to nine ruminally cannulated Rambouillet or Columbia wether lambs (avg wt 28.6 kg) in two randomized complete block experiments. An alfalfa hay-corn mixture at 2.1% of body weight (10% corn) was used in Exp. 1. In Exp. 2, 2.7% of body weight (25% corn; Exp. 2) was fed. Ruminal samples were collected at 0, 4, 8, 12 and 24 h postfeeding on d 17 of each 22-d period to measure fluid dilution rate and fermentation characteristics. An intraruminal dose of Yb-labeled hay followed by fecal sampling on d 19 through 22 was used to estimate particulate passage and fecal output. Ruminal pH, NH3 concentrations, total volatile fatty acid and proportion of individual acids were not influenced (P greater than .10) by the addition of either level of enzyme preparation in either Exp. 1 or 2. Dry matter digestibility also showed no effect (P greater than .10) of enzyme preparation added to either diet. In Exp. 1, wethers receiving 35 g/d of the enzyme preparation had greater cell wall digestion (49.8%; P less than .05) than wethers receiving either 22 g/d or no enzyme preparation (45.7 and 42.9%, respectively). In Exp. 2, with a 25% corn diet, no influence (P greater than .10) of enzyme preparation was noted on cell wall digestibility. Particulate and ruminal fluid passage rate parameters remained unchanged (P greater than .10) by the addition of either level of enzyme preparation, regardless of the diet fed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗