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Impaired function of the levator ani muscle in the grand multipara and great grand multipara.

Repeated deliveries might disturb the levator function and increase defecation disorders. In this prospective study, we determined the electric activity of the levator ani muscle (LAM) in nullipara, multipara, grand multipara, and great grand multipara (20 subjects for each group). Multiparity, grand multiparity, and great grand multiparity were defined as women having 2 - 5, 6 - 9, and 10 and over deliveries, respectively. The number of deliveries of multipara, grand multipara and great grand multipara were 4.05 +/- 1.14 (2 - 5), 7.55 +/- 1.23 (6 - 9) and 12.2 +/- 2.16 (10 - 17), respectively. All women were asked whether they had experienced constipation, fecal or urinary incontinence, and/or pelvic pain. All women were also evaluated for pelvic organ prolapse. Electromyography (EMG) of the LAM at rest and on contraction was recorded. EMG is an electrical recording of muscle activity. Constipation, incontinence and pelvic organ prolapse were encountered in multipara, grandmultipara and great grand multipara women. The LAM EMG at rest and on contraction in the nullipara was accepted as control. Both the resting and contractile activities of the LAM were as follows: nullipara > multipara > grand multipara > great grand multipara. These findings indicate that levator dysfunction and defecation disorders are increased with repeated deliveries because of pudendal and/or levator ani nerve injury and traumatic injury to the LAM occurred with the mechanical stresses of vaginal deliveries.

Adult↗

Insulin-like growth factor-I and its association with binding proteins in bovine milk.

Immunoreactive insulin-like growth factor-1 (IGF-I in bovine milk was quantified. IGF-I was principally assoication with an approximately 45 kDa binding protein. In addition, a small fraction of IGF-I occurred at a molecular weight approximately the same as that of unbound IGF-I. Available binding sites existed on the approximately 45 kDa binding protein. Bound IGF-I was readily dissociated from binding protein by acid treatment. When IGF-I was estimated in milk obtained from primiparous and multiparous cows, mutiparous cows had a higher concentration (40 nmol/1) [corrected] at parturition than primiparous cows (19.2 nmol/1) [corrected]. By day 2 of lactation, IGF-I concentrations were 30 and 50% of initial estimates for multiparous and primiparous cows respectively. the final IGF-I concentration, on day 56 of lactation, was 4.5 nmol/1 [corrected] for combined parity groups. At parturition in multiparous cows, the mass of IGF-I was estimated at 183 and 157 nmol [corrected] for blood and milk pools respectively. Milk, therefore, represents a substantial pool of IGF-I in the cow. The mechanism of the appearance of IGF-I in bovine milk is unknown.

Animals↗

Reflux in the left ovarian vein: analysis of MDCT findings in asymptomatic women.

OBJECTIVE: The aim of this study was to clarify the CT features of ovarian vein reflux in asymptomatic women and to determine the possible cause of the reflux. MATERIALS AND METHODS: One hundred ten multiparous or uniparous and 41 nulliparous asymptomatic women were examined on MDCT. Degree, pathway, and associated findings of ovarian vein reflux were evaluated. We measured the diameters of the left renal vein (LRV), the ovarian veins, and the parauterine veins. Ratios of LRV diameters (lateral-aortomesenteric) were obtained. These data were then compared between the women with reflux and those without reflux. RESULTS: Reflux was found in 44% (48/110) of parous and 5% (2/41) of nulliparous women. Reflux flowed into the right ovarian vein through the parauterine and uterine veins in 25 women. Twenty-four of these 25 women were multiparous. In these cases, the parauterine veins showed varicose dilation (5.9 +/- 1.6 mm [mean +/- SD]). There was a statistically significant difference in left ovarian vein diameter (8.3 +/- 2.1 mm vs 4.9 +/- 1.3 mm, p < 0.0001) between parous women with reflux and those without reflux, respectively. The LRV diameter ratio (lateral-aortomesenteric) was also statistically significant (3.6 +/- 1.3 vs 1.7 +/- 0.7, p < 0.0001) between the same two groups. CONCLUSION: Reflux into the left ovarian vein is seen up into the contralateral ovarian plexus by passing through the dilated parauterine and uterine veins. This CT finding is common in asymptomatic multiparous women. Narrowing of the LRV at its aortomesenteric portion can be one of the causes of such reflux.

Adult↗

Glucocorticoid receptor down-regulation in neutrophils of periparturient cows.

OBJECTIVE: To determine effects of parturition on glucocorticoid receptor (GR) expression in neutrophils, serum cortisol concentration, and total blood leukocyte and neutrophil counts in periparturient dairy cows. ANIMALS: 23 Holstein cows. PROCEDURE: Blood samples were collected from 8 multiparous and 5 primiparous periparturient cows at various times from 28 days before parturition until 14 days after parturition. Glucocorticoid receptor expression in neutrophils, serum cortisol concentration, and total blood leukocyte and neutrophil counts were determined. Results were compared with results from control samples obtained from 5 multiparous and 5 primiparous Holstein cows in midpregnancy. RESULTS: Neutrophils from periparturient cows had 49% reduction in GR expression at calving, compared with GR expression 2 to 4 weeks before calving, and 39% reduction, compared with neutrophils from cows in midpregnancy. Reduction in neutrophil GR expression began 1 week before calving and was most severe at calving and 24 hours after calving; a significant difference in GR expression was detected between primiparous and multiparous cows. Serum cortisol concentrations and total leukocyte and neutrophil counts were significantly increased at calving and returned to baseline values by 24 hours after calving. Significant negative correlations were detected between neutrophil GR expression and serum cortisol concentration, total leukocyte count, and neutrophil count. CONCLUSIONS AND CLINICAL RELEVANCE: Reduced GR expression in blood neutrophils of periparturient dairy cows was associated with increased serum cortisol concentrations, leukocytosis, and neutrophilia. Thus, GR down-regulation in neutrophils may be involved in periparturient neutrophil dysregulation and may cause increased susceptibility to mastitis.

Animals↗

Effect of fructose consumption during lactation on sow and litter performance and sow plasma constituents.

The effects of dietary consumption of high-fructose corn syrup (HFCS) and dextrose during a 28-d lactation on sow and litter performance and sow plasma constituents were examined in 45 multiparous and 36 primiparous crossbred sows. Isocaloric and isonitrogenous corn-soybean meal diets were formulated to contain either 20% fructose or 20% glucose. Diets were fed on a metabolic BW basis from d 0 to d 28 of lactation. Litter and pig weights on d 28 were not affected (P greater than .05) by treatment. Litter size was greater (P less than .10) at weaning for primiparous sows fed HFCS, but multiparous sows weaned heavier (P less than .05) pigs. Sow weight change during lactation was not influenced by diet, but primiparous sows lost more (P less than .05) weight during lactation and had longer intervals to estrus than multiparous sows did. Milk yields on d 17 and 21 of lactation were not different (P greater than .05) for sows fed HFCS vs dextrose, but sows fed HFCS tended to have greater (P = .05) percentage of milk fat. Preprandial concentrations of fructose in plasma were low in sows fed HFCS and nondetectable in those fed dextrose but were elevated (P less than .05) after consumption of HFCS. Conversely, similar (P greater than .05) concentrations of glucose in plasma preprandially were followed by greater (P less than .05) postprandial glucose concentrations in sows fed dextrose. Although postprandial concentrations of insulin were not affected (P greater than .05) by diet, sows fed dextrose had greater (P less than .05) preprandial insulin concentrations in plasma. Concentrations of nonesterified fatty acids and growth hormone in plasma and response to a glucose challenge were not affected (P greater than .05) by feeding HFCS. However, concentrations of insulin in plasma following glucose infusion were less (P less than .05) during the glucose challenge period on d 25 than on d 13 of lactation.

Animals↗

Influences of parity and level of feed intake on reproductive response to insulin administration after weaning in sows.

In three experiments, the influence of insulin administered after weaning was examined in primiparous sows given extra feed or in primiparous compared to multiparous sows. In Exp. 1, 171 primiparous and 231 multiparous crossbred sows on a commercial farm were injected with 0.4 IU/kg BW insulin (Eli Lilly Lente Iletin II) or saline for 4 d beginning the day after weaning (d 0) and were fed 2.3 kg/d until mating. In Exp. 2, 153 primiparous sows from the same farm as those in Exp. 1 were injected with insulin or saline as in Exp. 1 and were fed 2.7 or 3.6 kg/d until mating. In Exp. 3, 63 primiparous crossbred sows were injected with insulin or saline as described above and fed either 2.3 or 4.5 kg/d for 5 d after weaning and were remated. On the commercial farm (Exp. 1 and 2), insulin administration increased percentage in estrus for primiparous sows compared to multiparous sows (treatment x parity interaction, P < 0.02) but tended to lower litter size in primiparous sows (treatment x parity interaction, P < 0.06). In Exp. 2, insulin combined with extra feed increased (P < 0.05) litter size by two pigs but tended (P < 0.07) to decrease farrowing rate in that group (treatment x feed interaction). Weaning-to-estrus interval, pregnancy rate, ovulation rate, and embryo survival were not influenced by treatment or feeding level (Exp. 3); however, postweaning intake and embryo survival were negatively related for saline-treated sows only (r = -0.55; P < 0.01), and backfat depth at weaning and embryo survival were positively related for insulin-treated sows only (r = 0.44; P < 0.05). Overall, insulin administration differentially influenced reproduction in primiparous sows and may have interacted with metabolic or nutritional state of the animal.

Adipose Tissue↗

Dietary lysine and threonine requirements of the pregnant sow estimated by nitrogen balance.

Two experiments were conducted to determine the lysine and threonine requirements of gestating sows. In the first experiment, four levels of lysine (0.34,0.42,0.48, and 0.56% crude lysine, and 0.24,0.31, 0.38, and 0.45% standardized ileal digestible lysine) were compared in eight multiparous Large White sows. Each sow received successively the four diets according to a Latin-square experimental design. Nitrogen balance was measured over 11 d after a 10-d period of adaptation to the experimental diet. In the second experiment, four threonine/lysine ratios (0.63, 0.73, 0.80, and 0.89 on a crude basis and 0.61, 0.71, 0.77, and 0.87 on a standardized ileal digestible amino acid basis) were compared in 16 multiparous sows, according to a Latin-square experimental design. The standardized ileal digestibility of amino acids in the experimental diets was determined with ileo-rectal anastomized growing pigs. In the first experiment, nitrogen retention was affected by lysine supply (linear, P < 0.001; quadratic, P < 0.04). Nitrogen retention was lowest for treatment 1 (8.0 g/ d) and highest for treatments 3 and 4 that did not differ. Nitrogen retention plateaued at 14.7 g/d in sows consuming 10.5 g/d of digestible lysine. The maintenance requirement for digestible lysine was calculated to be 27 mg/kg BW(0.75) with an efficiency of utilization of digestible lysine above maintenance at 59%. In the second experiment, nitrogen retention was affected (P < 0.03) by the threonine:lysine ratio. It was lower for the lowest threonine:lysine ratio (0.63) than for the other three treatments that did not differ among each other. These results indicate that the optimal standardized digestible threonine:lysine ratio appears to be about 0.71 for multiparous gestating sows.

Animal Nutritional Physiological Phenomena↗

Estrous behavior and initiation of estrous cycles in postpartum Brahman-influenced cows after treatment with progesterone and prostaglandin F2alpha.

Spring-calving, crossbred (1/4 to 3/8 Brahman) primiparous (n = 56) and multiparous (n = 102) beef cows were used to evaluate the effects of progesterone, delivered via a controlled internal drug-releasing (CIDR) device, and prostaglandin F(2alpha) (PGF(2alpha)) on estrous behavior, synchronization rate, initiation of estrous cycles, and pregnancy rate during a 2-yr period. To determine luteal activity, weekly blood samples were collected 3 wk before initiation of a 75-d breeding season. Treated cows received a CIDR for 7 d beginning on d -7 of the breeding season. On d 0, CIDR were removed, and cows receiving CIDR were administered PGF(2alpha); control cows received no treatment. Cows were exposed to bulls, and estrous activity was monitored using a radiotelemetry system for the first 30 d of the breeding season. Treatment with CIDR-PGF(2alpha) increased (P < 0.05) the number of mounts received (22.5 +/- 3.0 vs. 13.7 +/- 3.9 for CIDR-PGF(2alpha) vs. untreated control cows, respectively) but did not influence duration of estrus or quiescence between mounts. Number of mounts received and duration of estrus were greater (P < 0.05) in multiparous compared with primiparous cows. Synchronization of estrus was greater (P < 0.05) in cows treated with CIDR-PGF(2alpha) (56%) compared with control cows (13%) during the first 3 d of the breeding season. More (P < 0.05) anestrous cows treated with CIDR-PGF(2alpha) than anestrous control cows were in estrus during the first 3 d (59 vs. 12%) and 30 d (82 vs. 63%) of the breeding season. Treatment with CIDR-PGF(2alpha) decreased (P < 0.05) the interval to first estrus after treatment during the first 30 d of the breeding season compared with control cows (5.5 +/- 1.1 vs. 9.0 +/- 1.4 d). First service conception rate was greater (P < 0.05) in CIDR-PGF(2alpha)-treated cows compared with control cows. Cyclic cows at initiation of the breeding season had an increased (P < 0.05) 75-d pregnancy rate compared with anestrous cows, and the pregnancy rate tended (P = 0.10) to be greater in multiparous compared with primiparous cows. We conclude that treatment of Brahman-influenced cows with progesterone via a CIDR for 7 d, along with administration of PGF(2alpha) at CIDR removal, increases the number of mounts received, improves synchronization and first service conception rates, decreases the interval to first estrus after treatment, and may be effective at inducing estrous cycles in anestrous cows.

Animals↗

Pituitary-ovarian relationships during the estrous cycle and the influence of parity in an inbred strain of miniature swine.

Pituitary-ovarian function was analyzed in a strain of miniature swine previously shown to produce a low ovulation rate resulting in the formation of only 8.6 corpora lutea (CL)/animal. Five multiparous (M) and four nulliparous (N) miniature pigs with a mean inbreeding coefficient of .39 were monitored for estrous behavior through four consecutive estrous cycles. Daily blood samples were collected from 5 d before to 5 d after the onset of the second, third and fourth estrus and at 48-h intervals during the remainder of the second and third estrous cycle. Laparoscopy was used to examine the ovaries 1 and 5 d after onset of the third estrus and 2 d after the beginning of the fourth estrus. For the entire group, temporal fluctuations among serum estradiol-17 beta, luteinizing hormone (LH) and progesterone concentrations and sexual behavior were similar to previously published data in standard swine breeds. Although the mean lengths of the estrous cycle were not different (P greater than .05) between parity subgroups (M, 23 +/- 1.3 vs N, 22 +/- .7 d), multiparous pigs were in estrus longer (P less than .05) than nulliparous females (M, 3.7 +/- .2 vs N, 2.2 +/- .4 d). Parity subgroups were similar with respect to the mean number of follicles forming CL (M, 8.8 +/- .7 vs N, 9.2 +/- .2). Although an average of 6.2 +/- 2.1 CL had formed by 24-h after onset of estrus in the nulliparous subgroup, no CL were detected in the multiparous subgroup at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effect of boar presence before and after weaning on estrus and ovulation in sows.

Two hundred sixty-two sows were used to investigate the effects of boar exposure during the last week of nursing (BPRE) and after weaning (BPOST) on the return to estrus. Because approximately one-half of the sows were weaning their first litter, a third factor, primiparous vs multiparous (LITT), was considered in the statistical analysis. To evaluate the effect of treatment on ovarian activity, the sows were also blood-sampled twice weekly for 3 wk after weaning for the measurement of plasma progesterone concentrations as an index of ovulation. Boar exposure after weaning was the most important stimulus of early ovulation and estrus after weaning (P less than .001). A greater proportion of first-litter sows exhibited estrus later (P less than .02) and ovulated later (P less than .09) than did multiparous sows. First-litter sows were unaffected (P greater than .10) by boar exposure before weaning. Multiparous sows were sensitive to boar exposure during nursing. Maximal boar exposure for these sows (BPRE + BPOST) resulted in 95% of sows in estrus and ovulating within 20 d of weaning. No boar exposure resulted in 45% and 38% anestrus and anovulatory sows. Boar exposure, either before or after weaning, was effective in reducing the number of anestrus and anovulatory sows to between 15 to 30%. The effects of BPRE and BPOST on return to ovulation were additive and approximately equal.

Animals↗

Cervical priming and labor induction with vaginal application of 3 mg PGE2 in suppositories in term pregnant women with premature rupture of amniotic membranes and unfavorable cervix.

Sixty-one term pregnant women, 29 nulliparous (Group A) and 32 multiparous (Group B) with unfavorable cervix and premature rupture of the membranes (PROM) were given 3 mg PGE2 in suppository form for cervical ripening and labor induction. Five hours after starting the treatment, 12 women of the 29 in Group A and 21 of the 31 in Group B had a favorable cervix and established labor. The remaining 17 nulliparae and 11 multiparae still had an unfavorable cervix and were then given another PGE2 suppository. Until the next morning, i.e. within 24 h, 19 nulliparous and 22 multiparous women gave birth whereas a further 5 nulliparous women who now had favorable cervix but no uterine contractions were delivered after stimulation with intravenous oxytocin. The remaining undelivered women were given another PGE2 suppository. With or without additional oxytocin stimulation, all but 2 multiparous women could be delivered within a further 12 hours. The total number of instrumental deliveries in Group A was 2 caesarean sections due to disproportion (7%) and 5 ventouses. In Group B, 3 caesarean sections (9%) had to be carried out, one due to fetal distress and 2 due to failed induction. From the results of this study we conclude that vaginal application of 3 mg PGE2 in suppository form can be used to induce labor in patients with PROM and unripe cervix. However, when the results are compared with those obtained in previous studies after application of PGE2 in gel, the latter technique seems preferable.

Cervix Uteri↗

Corn silage hybrid effects on intake, digestion, and milk production by dairy cows.

Three corn hybrids harvested as whole-plant silage were evaluated in three separate feeding trials with lactating dairy cows. In trial 1, 24 multiparous Holstein cows were used in a replicated 4 x 4 Latin square with 28-d periods. Treatments were conventional (Pioneer 3563) and leafy (Mycogen TMF 106) corn silage hybrids, each planted at low (59,000 plants/ha) and high (79,000 plants/ha) plant populations. There were no milk production differences between treatments. Total-tract digestibility of dietary starch was higher for leafy compared with conventional corn hybrids. In trial 2, 26 multiparous Holstein cows were assigned randomly to diets containing either conventional (48% forage diet) or brown-midrib (60% forage diet) corn silage in a crossover design with 8-wk periods. Milk yield was lower, but milk fat percentage and yield were higher, for the high-forage diet containing brown-midrib corn silage. In trial 3, 24 multiparous Holstein cows were used in a replicated 4 x 4 Latin square with 28-d periods. Treatments were corn silage at two concentrations of neutral detergent fiber (Garst 8751, 39.2% NDF; Cargill 3677, 32.8% NDF) each fed in normal- (53% of dry matter) and high- (61 to 67% of dry matter) forage diets. Milk production was not different between corn hybrids. Increased concentrate supplementation increased DMI and milk production. There were minimal benefits to the feeding of leafy or low-fiber corn silage hybrids. Feeding brown-midrib corn silage in a high-forage diet increased milk fat percentage and yield compared with conventional corn silage fed in a normal-forage diet.

Animals↗

Timing of onset of somatotropin supplementation on reproductive performance in dairy cows.

The objective of this field trial was to determine whether delaying the start of recombinant bovine somatotropin (rbST) supplementation from 9 to 10 wk postpartum to 17 to 18 wk postpartum would improve reproductive performance in lactating dairy cows. Cows from nine herds (n = 798 cows; 766 Holsteins, 32 Jerseys) were assigned at random to receive rbST supplementation at 14-d intervals beginning during wk 9 to 10 (n = 399) or wk 17 to 18 (n = 399) after calving. Effects of herd, season of calving, parity, and onset of rbST supplementation (9 to 10 wk vs. 17 to 18 wk) on days to first service and days open were determined. In primiparous but not multiparous cows, there tended to be fewer days to first service and fewer days open when onset of rbST supplementation was delayed. Percentages of cows pregnant at 150, 200, and 250 d postpartum were also examined. Time of onset of rbST did not affect percentages of multiparous cows pregnant at 150, 200, and 250 d postpartum. However, there appeared to be a slight tendency for percentages of pregnant primiparous cows to be greater at 200 and 250 d postpartum for those receiving rbST supplementation beginning at 17 to 18 wk compared to those receiving rbST starting at 9 to 10 wk. In conclusion, delaying the start of rbST supplementation to wk 17 to 18 postpartum had no beneficial effect on reproductive performance of multiparous cows but tended to improve some measures of reproductive performance in primiparous cows.

Animals↗

The impact of parity and duration of biotin supplementation on white line disease lameness in dairy cattle.

A field study was conducted to examine effects of oral biotin supplementation for up to 18 mo on risks of lameness in dairy cows. The study included a total of 900 cattle from five dairy farms in Gloucestershire, southwest U.K., in a within-herd randomized control trial. The data from this trial were used in this paper to investigate the impact of parity and duration of supplementation with oral biotin at 20 mg/d on white line disease (WLD) lameness. Analysis of the data indicated that WLD increased with increasing parity independent of biotin supplementation from approximately two cases per 100 cow years in primiparous cows to 15.5 cases per 100 cow years in all multiparous cows, but up to 47.7 cases per 100 cow years for cows in parities > or = 5. Supplementation with biotin reduced WLD lameness by 45% in multiparous cows down to 8.5 cases per 100 cow years, whereas the effect of biotin supplementation in primiparous cows was not significant. Although numerical reductions in WLD lameness were observed for shorter periods of supplementation, a supplementation length of at least 6 mo was required to significantly reduce the risk of WLD lameness in multiparous cows. The effect of biotin supplementation in reducing lameness has potential impact for both animal welfare and farm economics.

Administration, Oral↗

Changes in cisternal udder compartment induced by milking interval in dairy goats milked once or twice daily.

Fourteen Murciano-Granadina dairy goats were used to evaluate udder compartments (cisternal and alveolar) and cisternal recoil after an oxytocin (OT) challenge at different milking intervals (8, 16, and 24 h) during wk 7 of lactation. Goats were milked once (1x; n = 7) or twice (2x; n = 7) daily from wk 2 of lactation. Average milk yields for wk 4 and 8 were 1.76 and 2.24 L/d, for goats milked 1x and 2x, respectively. For each half udder, cisternal area was measured by ultrasonography and cisternal milk was measured by machine milking after i.v. injection of an OT receptor blocking agent. Alveolar milk was then obtained after i.v. injection of OT. Regardless of milking frequency, alveolar milk increased from 8 to 16 h after milking, but did not change thereafter. Cisternal area and cisternal milk increased linearly (R2 = 0.96 to 0.99) up to 24 h, indicating continuous milk storage in the cistern at any alveoli filling degree. Cisternal to alveolar ratio increased with milking interval (from 57:43 to 75:25), but differences between milking intervals were significant at 8 h only, at which time goats milked 2x showed a greater ratio (1x = 51:49; 2x = 62:38). Despite extended milking intervals, cisterns of goats milked 1x did not become larger than cisterns of goats milked 2x after 5 wk of treatment. The highest correlation between cisternal area and cisternal milk was detected at 8 h after milking (r = 0.74). Primiparous goats had smaller cisternal areas and less cisternal milk than multiparous goats at all milking intervals. Cisternal recoil was studied in a sample of multiparous goats milked 1x (n = 4) and 2x (n = 4) by scanning cisterns by ultrasonography at 0, 5, 15, and 30 min after an OT challenge for each milking interval. Cisternal area increased after OT injection for the 8- and 16-h milking intervals, but no differences were observed for the 24-h interval. Unlike cows, no changes in cisternal area were observed after OT injection, indicating the absence of cisternal recoil in goats. We conclude that goats show a large cisternal compartment that increases linearly after milking. Nevertheless, cisternal size did not increased after 1x milking, probably because of lesser milk yield. Multiparous goats had larger cisterns than primiparous goats and were able to store more milk in their cisterns at all milking intervals. Because of the high capacity of goat cisterns, no milk return from cistern to alveoli is expected if milking is delayed after milk letdown.

Animals↗

Statistical evaluation of factors and interactions affecting dairy herd improvement milk urea nitrogen in commercial midwest dairy herds.

In this study, 400,729 Dairy Herd Improvement (DHI) records collected on 77,178 cows in 692 Midwest herds over 29 mo (January 1999 to May 2001) were used to analyze milk urea nitrogen (MUN) as collected the day of the test in 6 breeds. Records of Holsteins, Jerseys, and Brown Swiss were subjected to stepwise backward elimination analysis with a model including parity (primiparous vs. multiparous cows), sample type (morning vs. evening), milking frequency (2x vs. 3x [Holstein only]), season (winter, spring, summer, and fall), yield of fat-corrected milk (FCM) classified into 1 of 3 FCM categories (FCMc) and all possible higher-order interactions. Results indicated that FCMc contributed to test-day MUN variation in multiparous, but not primiparous, Holsteins. Sample type and season were significant in both parity groups; milking frequency was not significant, but milking frequency x season and milking frequency x FCMc were significant in both parity groups. The nature of these interactions differed for each parity group. For Jersey and Brown Swiss data analyzed by sample type separately, parity was not significant but tended to interact with FCMc, whereas season, FCMc, and season x FCMc were generally significant. Mean test-day MUN was 12.7, 14.6, and 14.4 mg/dL, with 24, 45, and 42% of records above 14.5 mg/dL in Holsteins, Jerseys, and Brown Swiss in single-breed herds, respectively. In Holsteins, MUN peaked at 7 to 10 d in milk (DIM), declined until 28 to 35 DIM, and rose again thereafter. In primiparous Holsteins, MUN did not change with FCM <or=42 kg/d, but for higher FCM yield, MUN declined linearly by 0.05 mg/dL per kilogram of FCM. In multiparous Holsteins, MUN increased by 0.06 and 0.03 mg/dL per kilogram of FCM as FCM yield increased from 5 to 29 and from 30 to 59 kg/d, respectively, but decreased by 0.06 mg/dL as FCM yield increased from 60 to 85 kg/d. The use of adjustment coefficients may facilitate interpretation of test-day MUN on commercial herds. Research should focus on the biological significance of the pattern of change in MUN the first few weeks postpartum and the drop in MUN in unusually high-producing cows.

Analysis of Variance↗

Effects of feeding propionibacteria to dairy cows on milk yield, milk components, and reproduction.

Two weeks before parturition, 38 Holstein primiparous and multiparous cows were assigned to 1 of 3 treatment groups: control animals (n = 13) received regular total mixed rations (TMR), the low-dose group (n = 14) received the control TMR plus 6 x 10(10) cfu/cow of Propionibacterium strain P169 (P169), and the high-dose group (n = 11) received the control TMR plus 6 x 10(11) cfu/cow of P169 from -2 to 30 wk postpartum. Weekly milk samples were analyzed for percentage of milk fat, protein, lactose, and SNF, milk urea nitrogen, and somatic cell counts. Daily milk production expressed as 4% fat-corrected milk was affected by treatment and week x parity. High-dose and low-dose P169-treated cows exhibited 7.1 and 8.5% increases above controls in daily 4% fat-corrected milk, respectively. Treatment x parity and week significantly influenced percentage of milk fat, lactose, and protein, whereas treatment x parity and treatment x week influenced SNF. Ruminal propionate levels were influenced by treatment such that high-dose P169 cows had greater molar percentage of propionate than did low-dose P169 and control cows. Change in body weight postpartum was influenced by week x parity and treatment x parity such that high-dose and low-dose P169 multiparous cows exhibited a more rapid recovery of wk-1 body weight than did control multiparous cows. There was no treatment, parity, or interaction on days to first postpartum ovulation or on estrous behavior at 45 and 90 d postpartum. We concluded that P169 might have potential as an effective direct-fed microorganism to increase milk production in dairy cows.

Acetates↗

Effect of health status on culling and reproductive performance of Holstein cows.

Data were from 492 cows that calved between October 1976 and May 1977 in eight Holstein herds in Michigan. Cows were classified as those without any health-related problems during lactation; those with minor reproductive health problems not serious enough to require veterinary treatment; and those with health problems severe enough to require veterinary treatment. Among primiparous cows 4.4, 16.2, and 19.1% were culled from healthy, minor, and problem groups, whereas among multiparous cows, these percentages were 11.2, 19.1, and 31.7. Among healthy cows 33.3, 38.9, and 27.8% of total culls were classified as production, reproduction, and other. Among minor and problem cows, these percentages were 31.6, 42.1, and 26.3 and 22.6, 58.5, and 18.9. The odds of being culled were 4.3 and 5.2 times as great as for first lactation cows in minor and problem groups and 1.9 and 3.7 times as great as for older cows in the two health-problem groups. Primiparous cows in healthy group averaged 50 days to first detected estrus, 68 days to first service, and 95 days open. Least squares means for performance of primiparous cows in minor and problem groups and of multiparous cows in healthy, minor, and problem groups, as deviations from healthy cows, was days to first service, 9.1, 24.0, 2.0, 12.1, and 9.1; and days open, -7.0, 15.2, -9.1, 1.8, and 12.6. Primiparous cows with health problems were at a higher risk of being culled than multiparous cows with health problems.

Age Factors↗