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1.
This study was conducted to 1) determine milk yield of sows that were machine milked up to four times daily; 2) determine the effect of pig substitution on milk yield; 3) assess litter weight changes for sows that are milked; and 4) determine milk composition. Eight sows were milked four times daily to d 51 postpartum. Sows either maintained their own litter or had a week-old replacement litter to replace 25-d-old pigs. Individual gland milk yields were obtained on random days throughout lactation, and different diameter and weighted teat cups were rotated so that all glands received all combinations. Composite milk samples were analyzed for fat, protein, and somatic cells. Milk yields peaked at about 19 d postpartum and declined to 45 d postpartum in sows with their own litter, whereas milk yields peaked earlier and had a more dramatic decline after fostering of a younger litter. Litter weights were 17.1 +/- 1.0 kg at farrowing with 13.6 +/- .6 pigs born alive. Final litter weights were 34.4 +/- 11.7 kg for sows with replacement litters and 74.4 +/- 13.5 kg for sows with their own litters, and numbers of pigs weaned were 6.5 +/- 1.3 and 9.7 +/- 1.5, respectively. Milk fat was influenced by route of oxytocin administration (6.53 +/- .12 for i.v. vs 7.21 +/- .19% for i.m. administration; P < .05). Milk fat percentage was highest on d 2 and declined to 13 d postpartum. Milk protein was influenced by time of day of milking (lowest at the fourth milking, 5.57 +/- .11%) and followed a pattern similar to that for milk fat. Milk protein was affected in a linear manner by milk yield, with highest protein associated with lowest milk yields. Somatic cells in milk were influenced by litter replacement (P < .05) and oxytocin administration (P < .01). There was a linear increase in somatic cells from about 8 x 10(6) cells/mL milk at d 2 to more than 12 x 10(6) cells/mL milk at d 51 postpartum. These results show that pig replacement affects the amount of milk obtained. Moreover, milk composition changes throughout lactation. However, milk removal from sows has a severe impact on litter weight gains, and in systems where sow's milk is needed for commercial purposes, pig supplementation is necessary.  相似文献   

2.
Two experiments were conducted to determine whether milking beef cows two or five times daily in the presence or absence of their own nonsuckling calves would alter postpartum interval to first ovulation. Multiparous Angus x Hereford cow-calf pairs were assigned randomly between 13 and 18 d postpartum to treatments for 4 wk. In Exp. 1, pairs were assigned to six treatments: 1) calf was weaned permanently from its dam (CW; n = 9); 2) same as CW, but dam was milked twice daily (CW+2xM; n = 9); 3) calf was present continuously with its dam but restricted from contact with the udder (CR; n = 9); 4) same as CR, but dam was milked twice daily (CR+2xM; n = 9); 5) same as CR, but calf was allowed to suckle twice daily (CR+2xS; n = 8); and 6) calf was present continuously with its dam and suckled ad libitum (CP; n = 9). The interval from onset of treatments to first postpartum ovulation was shorter (P<.05) in the CW (14.1+/-3.1 d), CR (14.2+/-3.1 d), CW+2xM (13.0+/-3.1 d), and CR+2xM (17.2+/-3.1 d) than in the CP (34.7+/-3.1 d) and CR+2xS (33.9+/-3.3 d) treatments. Daily milk yield during treatment was greater (P<.01) for CR+2xM cows (7.1+/-.6 kg) than for CW+2xM cows (3.5+/-.6 kg). In Exp. 2, cow-calf pairs were assigned to three treatments: 1) CR+2xM (n = 10); 2) same as CR+2xM but cows were milked five times daily (CR+5xM; n = 10); or 3) CP (n = 10). The interval to first postpartum ovulation was shorter (P<.05) in the CR+2xM (23.6+/-3.5 d) and CR+5xM (26.1+/-3.7 d) treatments than in the CP (37.7+/-3.7 d) treatment. Daily milk yield during treatment was greater (P<.05) for CR+5xM cows (7.7+/-.6 kg) than for CR+2xM cows (6.4+/-.6 kg) by 17%. We conclude that suckling twice daily was sufficient to prolong postpartum anestrus as much as suckling ad libitum. Furthermore, milk removal by suckling, but not by milking two or five times daily, even in the presence of the cow's own nonsuckling calf, is essential to prolong postpartum anovulation.  相似文献   

3.
Two experiments were conducted to evaluate whether administration of recombinant porcine somatotropin (pST) to sows (Hampshire-Yorkshire) enhanced lactational performance. In Exp. 1, sows (n = 84) were fed a corn-soybean meal diet (17.8% CP), or a similar diet with 8% added fat, from d 108 of gestation to d 28 of lactation. Half of the sows fed each diet were injected with 6 mg/d of pST from d 108 of gestation to d 24 of lactation. Diets were fed at 2.27 kg/d from d 108 of gestation until farrowing and then were self-fed during lactation. By d 3 of lactation, litter size was standardized at 8 to 10 pigs per litter. Treating sows with pST resulted in a 10-fold increase (P less than .001) in serum somatotropin at 4 h postinjection. Serum glucose was increased (P less than .01) and serum triglycerides, creatinine, and urea N were decreased (P less than .01) by pST. During the summer, apparent heat stress occurred in pST-treated sows, resulting in 14 deaths. Most (10) of the deaths occurred just before, during, or shortly after farrowing. Fewer (P less than .08) deaths occurred when pST-treated sows were fed the diet with added fat. Sows treated with pST consumed less feed (P less than .10) and lost more backfat (P less than .10) during lactation than controls. Increasing the dietary fat did not prevent these changes. Weaning weights of pigs and milk yield of sows (estimated by deuterium oxide dilution) were not affected by pST treatment. In Exp. 2, sows (n = 42) were injected weekly with 0 or 70 mg of pST on d 3, 10, 17, and 24 of lactation. Litters were standardized by d 3 at 8 to 10 pigs, and sows were fed the same control (low fat) diet as in Exp. 1. Sows treated with pST consumed less feed and lost more weight and backfat during lactation than untreated sows. Litter size, average pig weaning weights, and milk yield were not influenced by pST treatment. These data indicate that a 6-mg daily injection of pST from 6 d prepartum to d 24 of lactation or a 70-mg weekly injection of pST from 3 d postpartum to d 24 of lactation does not increase milk production in lactating sows.  相似文献   

4.
Two experiments were conducted to determine whether exposure to a photoperiod of artificial long days in autumn increased milk yield in subtropical goats milked once (Exp. I) or twice daily (Exp. II). In Exp. I, starting at d 10 of lactation, 1 group of does was kept under naturally decreasing photoperiod (DD1X; n = 8), whereas the other group was submitted to an artificial photoperiod of long days (LD1X; n = 8; 16 h light:8 h darkness). The kids were weaned 28 d after parturition, and dams were manually milked once daily. Milk yield and milk components (fat, protein, and lactose) were assessed up to 140 d of lactation. From d 0 to 28 of lactation (suckling phase), mean daily milk yield did not differ between DD1X and LD1X goats (2.3 ± 0.2 kg vs. 2.4 ± 0.2 kg; P = 0.717). However, between d 29 and 84 (early milking phase), mean daily milk yield was greater in LD1X does than in DD1X does (2.6 ± 0.1 kg vs. 2.1 ± 0.1 kg; P = 0.001). Finally, between d 85 and 140 (late milking phase), mean daily milk yield was greater in LD1X goats than in DD1X goats (P ≤ 0.05) only during the first 2 wk. In Exp. II, one group of goats was exposed to a photoperiod of naturally decreasing days (DD2X; n = 8) and another group was submitted to an artificial photoperiod of long days (LD2X; n = 7). In both groups, kids were weaned on d 28 of lactation and the dams were manually milked twice daily. During the nursing phase, mean daily milk yield did not differ between the DD2X and LD2X groups (2.5 ± 0.3 kg vs. 2.6 ± 0.2 kg; P = 0.767). In the early milking phase, mean daily milk yield was greater in LD2X than in DD2X goats (3.3 ± 0.2 kg vs. 2.8 ± 0.2 kg; P = 0.022), whereas during the late milking phase, milk yield did not differ between the 2 groups (P = 0.946). In both experiments, milk composition was not significantly influenced by exposure to long-day photoperiod. We conclude that, in subtropical female goats that start lactation in late autumn, exposure to an artificial long-day photoperiod stimulates milk yield, even if goats are milked once daily. In addition, combining exposure to long days with twice-daily milking will increase further milk yield in such goats without affecting milk components.  相似文献   

5.
Three experiments were conducted on Martina Franca jennies. Experiment 1 tested Wood's model for evaluating the lactation curve. Data from the entire lactation period of 12 jennies were used. The results showed that Wood's model was able to recognize the shape of the lactation curve from pooled data (r(2) = 0.11; P < 0.01), with the lactation peak occurring at 48 d. Individual curves showed wide variability. Experiment 2 aimed to evaluate the effects of the daily number of milkings (1, 3, or 6) and the interval between the separation of foals from dams and milking (2 or 3 h) on milk yield and udder health. Four groups of jennies (n = 5) were considered: 1 × 3H, milked once per day (1×) with a 3-h interval from the time of foal removal (3H) from the dams to mechanical milking (3-h interval); 3 × 3H, milked 3 times per day with 3-h intervals; 3 × 2H, milked 3 times per day with 2-h intervals; and 6 × 2H, milked 6 times per day with 2-h intervals. The milk somatic cell count (SCC) was monitored. Better efficiency was observed for 3 vs. 1 milking per day and for 3-h vs. 2-h intervals. The regimen of 6 daily milkings at 2-h intervals did not increase milk yield and was related to an increase in the SCC compared with 3 daily milkings. In Exp. 3, the effects of the interval from foal removal to milking (3, 5, or 8 h) on yield, gross chemical composition, organoleptic characteristics of the milk, and udder health of the jennies were evaluated. The effects of milking time were also evaluated. Twenty jennies milked twice daily (2×) were subdivided into 4 groups (n = 5): 2 × 3H, with milkings at 1200 h and 1900 h and an interval of 3 h; 2 × 5H, milked at 1200 h and 1900 h with a 5-h interval; 2 × 8H(1), milked at 1200 h and 2200 h with an 8-h interval; and 2 × 8H(2), milked at 0700 h and 1900 h with an 8-h interval. Milk yield was greater by 28.4% when an 8-h interval was used compared with a 3-h interval and at the morning vs. the evening milking. The milk yield per milking was greatest at 0700 h, indicating the existence of a circadian rhythm in milk secretion processes. Intervals of 5 and 8 h caused significant decreases in the fat and lactose content and organoleptic characteristics of the milk, whereas an 8-h interval led to an increase in the SCC. In conclusion, a milking regimen of twice-daily milking at 0700 h and 1900 h with an 8-h interval provided the maximum yield per day. In terms of milk quality, a 3-h interval yielded the best results.  相似文献   

6.
To investigate the effects of supplemental Se on the transfer of Se to nursing pigs when sows are fed diets containing a Se level above the NRC recommendation (0.15 ppm), sows were fed diets containing no supplemental Se or supplemental (0.3 ppm) Se from sodium selenite or Se yeast. A nonSe-fortified corn-soybean meal basal diet with a high endogenous Se content served as the negative control (0.20 to 0.23 ppm Se). Fifty-two sows were fed diets from 60 d prepartum until 14 d of lactation. Six sows per treatment were bled at 60 and 30 d prepartum, at farrowing, and at 14 d postpartum to measure serum Se concentrations. Colostrum was collected within 12 h postpartum, and milk was collected at 14 d of lactation. Blood was obtained from 3 pigs each from 12 litters per treatment at birth and at weaning (d 14), and pooled serum was analyzed for Se and immunoglobulin G concentrations and glutathione peroxidase activity. Regardless of treatment, serum Se in sows declined throughout gestation and gradually increased during lactation. Sows fed Se yeast tended (P < 0.06) to have greater serum Se at farrowing than sows fed unsupplemented diets. Colostrum and milk (d 14) Se concentrations increased (P < 0.01) when sows were fed Se from yeast but not from sodium selenite. At birth, serum Se was increased (P < 0.01) for pigs whose dams were fed Se yeast compared with pigs from sows fed the basal diet. At 14 d of age, there was no difference in serum Se concentration of pigs from dams fed any of the treatments. Pig serum immunoglobulin G concentrations and glutathione peroxidase-1 activity were unaffected by dietary Se source. Supplementation of gestating and lactating sow diets with Se (0.3 ppm) from an organic or inorganic source reduced the number of stillbirths per litter. However, only pigs born to sows fed organic Se (Se yeast) had greater serum Se at birth. Organic Se increased Se concentration of colostrum and 14-d milk to a greater degree than inorganic Se.  相似文献   

7.
Four experiments involving 265, 410, 894, and 554 sows (Exp. 1 to 4, respectively) were conducted to determine the effect of spray-dried plasma (SDP) at 0 or 0.25% (Exp. 1 and 2) and 0 or 0.50% (Exp. 3 and 4) in lactation diets on average daily feed disappearance (FD), sum of sow BW, fetal and placental loss from d 110 gestation to weaning (SWL), litter size at weaning, litter weight at weaning, and average days from weaning to first estrus (WEI). Experiments 1, 3, and 4 were conducted during summer months, and Exp. 2 was conducted during fall to winter months. Experiment 1 used only parity 1 and parity 2 sows and Exp. 4 used only mature (>2 parities) sows, whereas Exp. 2 and 3 used all parity groups. Sows fed SDP in Exp. 1 had increased (P < 0.01) FD and a tendency for reduced (P = 0.06) SWL and WEI (P = 0.06). Sows fed SDP in Exp. 2 had a tendency for increased (P = 0.09) sow BW at weaning and reduced (P = 0.09) SWL, whereas other variables were not different between diets. Parity 1 and 2 sows fed SDP in Exp. 3 had increased (P < 0.01) FD, but mature sows fed SDP had reduced (P = 0.02) FD. Pig survival and litter size at weaning for all parity groups was not different between diets. The WEI for parity 1 sows fed SDP was reduced (P = 0.02) and tended to be reduced (P = 0.10) for mature sows fed SDP, but was not different between diets for parity 2 sows. More parity 1 sows fed SDP were detected (P = 0.01) in estrus 4 to 6 d after weaning, and fewer were detected (P < 0.01) in estrus 6 d after weaning compared with control parity 1 sows. In Exp. 4, FD was reduced (P < 0.01) for mature sows fed SDP; however, litter weight and average pig BW at weaning was increased (P < 0.01) with more (P < 0.01) marketable pigs (pig BW > 3.6 kg) weaned per litter. Relatively low dietary levels of SDP (0.25 to 0.50%) fed to parity 1 sows farrowed during summer months increased lactation FD and reduced WEI. Mature sows fed SDP during summer months consumed less lactation feed without compromising WEI, but had an increased litter weight, average pig BW, and number of marketable pigs at weaning.  相似文献   

8.
The acyclic postpartum period in cows is prolonged due to frequent suckling when compared with twice daily milking. In conventional milking systems twice daily milking is common, while in automatic milking systems (AMS) three or more milkings are performed in early lactation. In this study, the hypothesis was tested that an increased milking frequency in AMS causes a delay in resumption of ovarian cyclicity postpartum and increases days open in German Fleckvieh cows (n = 124). Calvings were equally distributed throughout the 1-year experimental period. All cows were housed in one barn. Sixty-three cows were milked in an AMS (AC) and 61 cows were twice daily milked in a conventional milking parlour (PC). Forty-two AC and 36 PC remained in the herd until conception. After parturition, milk samples were analysed for progesterone twice weekly to record the ovarian activity until pregnancy was diagnosed. The first and the second ovulation were determined by the progesterone profile of each individual cow. The mean milking frequency during the first 3 weeks after parturition was higher in AC (3.17 +/- 0.09 milkings/day) than in PC (milked twice daily). The individual mean milking frequency of AC for the first 3 weeks of lactation ranged from 2.0 to 5.9 daily milkings. The time span from parturition until the first and second ovulation did not differ between AC and PC. However, first ovulation was observed earlier in primiparous (23 +/- 1 days) than in multiparous cows (29 +/- 1 days, P < 0.05). Within AC no relationship between milking frequency and duration of the acyclic period was observed. Days open did not significantly differ between AC and PC and between primiparous and multiparous cows. In conclusion, the increased milking frequency in AMS did neither cause a delay in resumption of ovarian cyclicity postpartum nor did it increase days open.  相似文献   

9.
A cooperative study involving six experiment stations and 236 crossbred litters was conducted to determine the effect of nominal nipple drinker water flows of 700 mL/min and 70 mL/min (actual = 701 and 76 mL/min, respectively) during winter (November through February; 124 litters) and summer (June through August; 112 litters) seasons on performance of lactating sows and their litters. Within a season, sows were paired according to expected farrowing date and assigned at random to crates. Water flow rate treatments were assigned at random to sows within pairs. Sows were housed in farrowing crates from d 109 of gestation until either d 21 (two stations) or d 28 of lactation (four stations). Within 24 h after farrowing, litters were adjusted to contain 8 to 12 piglets. Sow feed intake (SFI) and litter weight (LW) were recorded weekly. Sow weights were recorded at d 109 of gestation, d 0, and d 21 of lactation. Sows lactating beyond 21 d were also weighed on d 28. Analysis of covariance was applied to sow weight change, average daily SFI, and LW data where litter size after crossfostering was the covariate. Average ambient temperature 30 cm above the floor at 0830 and 1600 was 24.6 +/- 0.15 degrees C and 29.4 +/- 0.14 degrees C, respectively, during summer and 20.7 +/-0.13 degrees C and 21.8 +/- 0.11 degrees C during winter trials. Restricted drinker water flow rate decreased SFI (P < 0.01; 4.59 vs. 3.94 kg/d, respectively, for 700 and 70 mL/min) and increased BW loss (P < 0.01; 0.56 vs 0.89 kg/d, respectively for 700 and 70 mL/min) but did not affect litter size (P > 0.87) or LW (P > 0.89) during the first 21 d of lactation. During d 22 to 28, the 70 mL/min flow decreased SFI (P < 0.01; 5.02 vs. 4.47 kg/d respectively, for 700 and 70 mL/min). Over the 21-d lactation period, the 70 mL/min treatment depressed (P < 0.01) SFI more during the winter (5.12 vs. 4.24 kg/d for 700 and 70 mL/ min, respectively) than during the summer (4.05 vs 3.65 kg/d for 700 and 70 mL/min, respectively). Season affected SFI (P < 0.01; 4.68 vs. 3.85 kg/d, respectively, for winter and summer), sow weight loss (P < 0.001; 0.46 vs 0.83 kg/d, respectively, for winter and summer), and LW at 21 d (P < 0.05; 52.8 vs. 49.6 kg, respectively, for winter and summer) but not (P > 0.96) the number of pigs per litter. Results of this study suggest that ample access to drinking water and controlling ambient temperature during summer months are essential for sow and litter performance.  相似文献   

10.
Two experiments were conducted to determine the voluntary feed intake and performance of lactating sows fed diets containing a sucrose/milk chocolate product (MCP) blend (Exp. 1) or dried porcine solubles (DPS; Exp. 2). Dried porcine solubles is a coproduct of heparin extraction from porcine small intestines. In Exp. 1, mixed-parity sows (n = 108) at two research centers were assigned to a corn-soybean-meal-based diet formulated to contain 0.9% total lysine or a similar diet that contained 4% sucrose and 2% MCP on an as-fed basis. Sows were allowed ad libitum access to dietary treatments from the day of farrowing until pigs were weaned at approximately 21 d postpartum. Diet had no significant effect on voluntary feed intake of sows during lactation, backfat depth, or postweaning interval to estrus, but it had variable effects on body weight changes. Inclusion of the sucrose/MCP blend in diets elicited a 2% improvement in litter weaning weight at one research center and a 6% depression in litter weaning weight at the other center (diet x research center, P < 0.05). Litter size throughout lactation was unaffected by dietary treatment. In Exp. 2, mixed-parity sows (n = 119) at two research centers were assigned to corn-soybean meal-based diets formulated to contain 0.9% total lysine with 0, 1.5, or 3.0% added DPS. Sows were assigned to dietary treatments within research center, farrowing group, and parity at parturition. Dried porcine solubles tended to increase (P < 0.10) total feed consumed in the first 9 d of lactation and average daily feed intake over the entire lactation (6.03, 6.53, and 6.30 kg) for sows fed 0, 1.5, and 3.0% DPS, respectively. Litter size and weight on d 18 of lactation were not affected by concentration of DPS in the diet. Days from weaning to estrus and percentage of sows displaying estrus were not influenced by diet. We conclude that inclusion of the sucrose/MCP blend in the diet for lactating sows had no consistent effect on voluntary feed intake of sows and weight gain of nursing pigs. Inclusion of DPS at 1.5 or 3.0% tended to improve feed intake of lactating sows but had no significant influence on litter performance.  相似文献   

11.
Two experiments were conducted to examine the milk producing ability of Western White-Faced sheep and to identify traits that correlate well with milk production. In Exp. 1, 31 Targhee ewes were milked and five samples were taken during 107-d lactations in which the ewes nursed twin lambs. Milk yield and composition, lamb weights, ewe weights, wool growth, and udder size also were measured. In Exp. 2, 24 ewes (Rambouillet x Finn-Dorset) were separated from their lambs at 7 wk and milked twice per day for eight more weeks, during which milk yield and composition, feed consumption, udder width, and ewe weights were measured. Results from Exp. 1 showed that lamb 30-d weights, ewe weights at breeding time, and udder width at peak lactation were highly correlated with suckled milk yield (r = .81, .75 and .66, respectively). Results from Exp. 2 indicated that lamb weights and ewe weights were not useful for predicting milk yield in dairy ewes, but feed intake and udder width were (r = .74 and .86, respectively). Single-day milk yield measurements were excellent estimators of total lactation yield in both experiments. Milk yields averaged 1,714 g/d in the suckled ewes and 477 g/d in the dairy ewes.  相似文献   

12.
Boer and Boer crossbred meat-type does were used in two experiments to determine whether goat milk serum contains leptin and to investigate possible correlations of milk and serum leptin in does and subsequent growth of their offspring. Blood and milk samples were collected within 2 h of kidding (d 0) from 20 (Exp. 1; spring) or 22 does (Exp. 2; the following fall). Blood milk samples were then collected again on d 0.5, 1, 3, 5, 7, 14, 21, 28, 35, 42, 49, and 56 (Exp. 1) or d 0.5, 1, 2, 3, 4, 5, 6, 7, 14, and 21 (Exp. 2). Body weights of kids were recorded on d 0, and BW of kids and does were recorded weekly beginning on d 7 (kids) or 21 (does), with BCS also recorded for does beginning on d 28 for Exp. 1 and on d 0.5, 1, 2, 3, 4, 5, 6, 7, 14, and 21 for Exp. 2. Leptin was detected in colostral milk and was influenced by days postpartum, decreasing (P < 0.001) over time with an average of 4.4 +/- 0.3 ng/mL (Exp. 1) and 18.1 +/- 1.0 ng/mL (Exp. 2) on d 0 compared with 1.0 +/- 0.3 ng/mL on d 56 (Exp. 1) and 2.9 +/- 0.2 ng/mL on d 21 (Exp. 2). Day postpartum and milk serum leptin were negatively correlated (P < 0.001) for Exp. 1 (r = -0.27) and Exp. 2 (r = -0.46). For Exp. 1 only, blood serum leptin tended (P = 0.09) to be influenced by day, with a weak positive correlation (r = 0.15; P < 0.02). Weak positive correlations (P < 0.01) were found between blood serum leptin and doe BCS (r = 0.42 in Exp. 1, and r = 0.13 in Exp. 2) and doe BW (r = 0.44 in Exp. 1, and r = 0.26 in Exp. 2), with the absence of a stronger relationship likely due in part to the short time period measured and the lack of significant changes in BCS and BW during that time. In conclusion, leptin was present in milk and blood serum of does, and blood serum leptin was weakly correlated with doe BW and BCS, but it was not related to kid BW. Therefore, further studies are needed to clarify the relationships involving milk and serum leptin in goats.  相似文献   

13.
Release of oxytocin at suckling or milking may delay onset of estrous cycles in postpartum cows. Twenty lactating Holsteins of mixed parity were given 100 mU oxytocin iv (n = 10) or 2 ml saline (control; n = 10) via jugular catheters at 0530, 0930, 1730 and 2130 daily from calving (d o) until 28 d postpartum. All cows were milked twice daily at 0130 and 1330. Blood was collected thrice weekly (Monday, Wednesday, Friday at 0530) for 12 wk and analyzed by radioimmunoassay for progesterone and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) in serum. On d 12, blood was collected every 15 min for 6 h via jugular catheters and concentrations of luteinizing hormone (LH), cortisol and PGFM were determined. Rate of involution of the reproductive tract was estimated twice weekly by palpation per rectum. Overall mean, baseline concentrations, number of pulses/6 h, and pulse duration of LH on d 12 were similar among treatment groups. However, oxytocin seemed to reduce (P less than .10) pulse amplitude of LH in multiparous cows (.4 +/- .2 vs .8 +/- .1 ng/ml), but not in primiparous cows. Concentrations of cortisol and PGFM in serum on d 12 were unaffected by treatment. The average intervals from calving to first ovulation, based on changes of progesterone in serum and the intervals to first estrus, were similar between treatment groups. Rates of involution of the cervix and uterus also were similar between treatments. Milk yield, percent protein in milk and somatic cell counts did not differ between treatment groups. However, percent fat in milk tended to be higher (P less than .10) in cows given oxytocin than in controls (3.99 +/- .22 vs 3.68 +/- .21). These data indicate that multiple daily injections of oxytocin did not affect: 1) length of anestrus and anovulation in postpartum dairy cows, 2) LH release and 3) rates of cervical and uterine involution.  相似文献   

14.
Two experiments were conducted, involving 68 third-litter sows and 20 first-litter gilts in Exp. 1 and 82 first-litter gilts in Exp. 2. On d 108 of gestation, the dams were moved into individual crates, stratified by parity and breed, and randomly assigned within strata, to one of two treatments: (1) fed a basal 16% protein corn-soybean meal diet, 1.8 and 2.7 kg once daily before farrowing and for the first 7 d of lactation, respectively, and then ad libitum until pigs were weaned at 28 d of age, and (2) fed the basal diet plus 1 g of L-ascorbic acid (vitamin C)/dam daily from d 108 of gestation through d 7 of lactation and on the same feeding schedule as for treatment 1. In Exp. 1, no effect of vitamin C supplementation was observed in sows or gilts on total pigs born/litter, number of live pigs/litter or average live pig weight at birth, 7 or 28 d of age, or on plasma vitamin C concentration of dams at d 108 of gestation or d 7 of lactation or of pigs at birth, 7 or 28 d of age. However, there was a lower (P less than .01) plasma vitamin C concentration of the dams at d 7 of lactation than at d 108 of gestation. Plasma vitamin C concentration also declined (P less than .01) as pigs aged. In Exp. 2, with all gilts, vitamin C supplementation again showed no effect on any of the reproductive traits measured in Exp. 1. It is concluded that daily supplementation of 1 g of vitamin C to either sows or gilts from d 108 of gestation through d 7 of lactation has no beneficial effect on the reproductive or lactation performance of swine.  相似文献   

15.
The purpose of this study was to determine growth performance of nursing pigs in relationship to teat order and to observe teat preference by pigs. In the first experiment, litter size of 13 primiparous sows was adjusted to 9 (8.7 +/- 1.5) pigs and teat order of each litter was observed on the day before slaughter. Another group of eight sows was killed on d 0 (within 12 h after farrowing). In the second experiment, litter size was adjusted to 9 (8.9 +/- 1.4) pigs for 20 primiparous sows and teat order for each litter was observed 1 d before slaughter. The weights of sows and individual pigs were recorded at farrowing, weekly, and on the day before slaughter. Mammary glands were collected at slaughter on d 21 of lactation and trimmed of skin and the extraneous fat pad. Individual glands were separated, weighed, and ground for measurement of dry matter, dry fat-free tissue, protein, fat, ash, and DNA contents. Middle mammary glands had the greatest wet weight among glands obtained within 12 h after weaning (P < .05). For sows completing the 21 d lactation, only glands known to have been nursed were included in the data sets. Greater than 60% of the first four pairs of mammary glands were nursed, and less than 40% of the seventh and eighth glands were nursed by pigs during lactation. Pigs that nursed the first five pairs of anterior glands gained faster than pigs nursing the remaining glands. The first five pairs of anterior glands had greater wet and dry weights, and greater protein and DNA contents compared with the remaining glands. Pigs that nursed heavier glands gained weight faster (r = .68, P = .0001), and those heavier glands contained greater amounts of protein (r = .98, P = .0001) and DNA (r = .66, P = .0001). Variation in weight gain of pigs nursing the anterior and middle glands was not statistically significant. The functional superiority of anterior and middle glands was positively correlated with body weight gain of nursing pigs.  相似文献   

16.
Two experiments were conducted to assess the effects of feeding thyrotropin-releasing hormone (TRH) during lactation on sows. In Exp. 1, sows were fed 0, 1, 10, 100 or 1,000 mg TRH on d 10.8 +/- .4 (mean +/- SE) after parturition. Blood samples were taken from sows every 30 min from -2 h to 8 h and at 10, 12 and 18 h from feeding. Consumption of 100 or 1,000 mg TRH increased mean serum concentrations of thyroxine (T4; P less than .001), 1,000 mg TRH increased growth hormone (GH; P less than .06) and 100 or 1,000 mg TRH increased prolactin (PRL; P less than .01), but insulin (INS; P greater than .10) was unaffected by TRH. Serum concentrations of T4 were elevated within 2 to 4 h after feeding TRH and remained elevated for 12 to 18 h. Concentrations of GH and PRL began to increase immediately after feeding 100 or 1,000 mg TRH and remained elevated for 6 and 8 h, respectively. In Exp. 2, sows were fed 0 or 200 mg TRH from d 111 of gestation to weaning at 27.1 +/- .3 d of lactation. Consumption of TRH elevated concentrations of T4 at all stages of lactation and increased respiration rate on d 10 and d 20, heart rate on d 20, and milk production on d 20 of lactation. Consumption of TRH did not influence number of pigs born, number born alive, survival rate during lactation, sow body weight, heartgirth, backfat depth, feed disappearance, or milk production on d 10 of lactation. Piglets nursing sows fed TRH were similar in weight to piglets nursing sows not fed TRH on d 0 and 5 of lactation, but they were heavier on d 10 (P less than .07), 15 (P less than .001), 20 (P less than .001) and 27 (P less than .0001). Sows fed TRH took longer (P less than .001) to return to estrus after weaning than control sows. Results indicated that feeding TRH elevated T4, GH and PRL and that feeding TRH for the duration of lactation increased milk production on d 20 of lactation and increased weaning weights, but it delayed estrus after weaning.  相似文献   

17.
Twenty-eight primiparous sows were used to study nutrient mobilization among body tissues as influenced by litter size in lactating sows. Litter size was set to 6, 7, 8, 9, 10, 11, or 12 pigs within 48 h postpartum by cross-fostering. Four sows were allotted to each litter size group. Sows had 11.5 +/- 1.3 Mcal of ME and 39.3 +/- 4.4 g of lysine per day and were killed on d 20.6 +/- 1.1 of lactation. Liver, gastrointestinal tract (GIT, composed of the empty stomach, empty small and large intestines, cecum and rectum), reproductive tract, and other organs (excluding liver, GIT, reproductive tract, and mammary gland) were separated from the carcass. Gastrointestinal tracts were manually stripped of contents and flushed with water to remove digesta. Hot carcasses were split longitudinally at the midline after removing mammary glands and internal organs. Individual organs and carcasses were weighed then ground for chemical analysis. Dry matter, crude protein, fat, and ash contents were measured. As litter size increased, protein mobilization was linearly increased (P < 0.05) in carcass, GIT, and reproductive tract. Protein mobilization in liver was quadratically affected by litter size (P < 0.05). Fat mobilization was not affected by litter size. The amount of protein mobilized from carcass, GIT, liver, and reproductive tract in sows increased by 641 g as litter size increased by one pig from 6 to 12 pigs after a 21-d lactation. Carcass contributed the largest amount of protein (600 g for an additional pig) among body tissues, whereas the reproductive tract contributed the highest percentage (26%) of its protein among body tissues. Protein efficiency from milk to litter weight gain was 72% as litter size increased during a 21-d lactation. In feeding lactating sows, effect of litter size on nutrient mobilization from various tissues should be considered for minimizing the excess tissue mobilization during lactation.  相似文献   

18.
Twenty-eight primiparous sows were used to determine the effect of litter size on the growth of mammary glands and nursing pigs during lactation. Litter size was set to 6, 7, 8, 9, 10, 11, or 12 pigs by cross-fostering immediately after birth. Four sows were allotted to each litter-size group. Sows were allowed to consume a daily maximum of 13.6 Mcal ME and 46.3 g of lysine during lactation. Sows were slaughtered on d 21 (20.6+/-1.1) of lactation. Mammary glands were collected at slaughter and trimmed of skin and the extraneous fat pad. Each gland was separated, weighed, and ground for chemical analysis. Dry matter, dry fat-free tissue (DFFT), crude protein, ash, and DNA contents were measured. Only glands known to have been nursed were included in the data set. Wet and dry weights and the amounts of DFFT, protein, DNA, ash, and fat in individual nursed mammary glands linearly decreased (P<.05) as litter size increased. Percentages of DFFT, protein, and DNA were quadratically affected (P<.05) by litter size on d 21 of lactation. Total mammary wet and dry weights and total DFFT, protein, DNA, fat, and ash amount of all nursed mammary glands of each sow were increased as litter size increased (P<.05). Changing litter size from 6 to 12 pigs resulted in 2,098, 432, 253, 227, 4.4, 178, and 20 g increases in the amounts of total mammary wet weight, dry weight, DFFT, protein, DNA, fat, and ash, respectively, on d 21 of lactation. Litter weight gain was 18.1 kg greater in sows with 12 pigs than in sows with 6 pigs. Sows with a larger litter size had a greater increase in total mass of mammary gland tissue and litter weight but had lower growth of individual nursed mammary glands and individual pigs than sows with the smaller litter size. The need for nutrients to support additional mammary gland and litter growth as litter size increases should be considered when estimating nutrient requirements for lactating sows. Sows need an additional .96 g lysine per day to account for mammary gland growth for each pig added to a litter.  相似文献   

19.
A total of 146 primiparous sows was used in four replications of an experiment to investigate the effect of energy intake during a 28-d lactation on sow and litter performance. Dietary treatments consisted of three energy intakes; 10, 12 or 14 Mcal of metabolizable energy (ME) X sow-1 X d-1. All sows were fed equal amounts of crude protein, vitamins and minerals daily, which met or exceeded standard recommendations. The experiment was initiated at parturition. Sow weight and backfat loss during lactation decreased linearly (P less than .001) as energy intake increased. There were no differences in litter size at either 14 d of lactation or weaning. Pig weights on d 14 increased linearly (P less than .05) and litter weights tended to increase linearly (P = .13) as energy intake increased. At weaning, pig weights and litter weights increased (P less than .05) as sow energy intake increased. There were no significant differences in the percentages of sows in estrus by 7, 14, 21 and 70 d postweaning, but sows fed 10 Mcal ME/d had a slightly longer interval from weaning to first estrus than sows fed higher energy intakes. Serum urea concentrations of sows were inversely related to energy intake during lactation. Serum creatinine concentrations were not affected by energy intake. An intake of 10 Mcal ME/d by primiparous sows during a 28-d lactation resulted in reduced sow and litter performance; there was little difference between sows fed 12 and 14 Mcal ME/d.  相似文献   

20.
The aim of the study was to determine the association of automatic milking systems milking frequency (≤2.40, 2.41–2.80 and >2.80 times/day) in primiparous and multiparous cows with their daily milk yield and milkability. The analysis included of the milk production level and the interaction between milking frequency per day and daily milk yield. Regardless of the daily production level, most primiparous cows were milked 2.41–2.80 times/day and most multiparous cows >2.80 times/day. Higher daily milk yield and a more favourable effect of increasing milking frequency on this parameter were observed in multiparous cows, with an increase from 29.7?kg (milking frequency ≤2.40 times/day) to 31.1?kg milk (>2.80 times/day). In primiparous cows, this increase was smaller and amounted to 0.8?kg milk (from 29.2 to 30.0?kg).  相似文献   

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