[show abstract][hide abstract] ABSTRACT: This study was designed to 1) determine milk yield of sows that were machine milked; 2) assess the effects of pulsation rate, pulsation ratio, and pig removal on milk yield; and 3) assess litter weights. In Exp. 1, four sows were milked daily to 60 d postpartum. There were differences (P < .05) in milk yield among sows, the greatest being 1,898 mL/d. Daily milk yield peaked between 15 and 25 d postpartum. Litter weights were 18.0 +/- 1.0 kg at farrowing and 60.8 +/- 12.1 kg at d 60. In Exp. 2, four sows were milked daily for 28 d. Pulsation rate and ratio (150/min and 28:72, milk:rest, and 60/min and 50:50) were alternated on a daily basis and pigs were isolated for either 0 or 60 min before milking. The higher pulsation rate resulted in more milk per milking (202 +/- 13 vs 168 +/- 13 mL; P < .05). Pig removal resulted in 221 +/- 11 vs 148 +/- 14 mL milk (P < .01). Pig removal times and pulsation characteristics affect the amount of milk obtained, but milk removal from sows has a severe effect on litter weight. This system can be used to harvest sow's milk for pharmaceutical purposes, but supplementation of the pigs is necessary.
Journal of Animal Science 08/1999; 77(7):1620-3. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: 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.
Journal of Animal Science 08/1999; 77(7):1624-30. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: Our studies in transgenic animal bioreactors sought to determine the rate limitations in posttranslational processing of recombinant human protein C (rhPC) made in mammary gland of mice and pigs. Human protein C (hPC) is a complex plasma protein containing nine gamma-carboxylated glutamic acid (gla) residues that bind calcium at about 1 to 3 mM. Gamma carboxylation is a vitamin K-dependent posttranslational modification. The effect of rhPC synthesis rate on the extent of gamma-carboxylation of glutamic acid was studied. We have perturbed the biosynthesis of rhPC by using two different transgenes to direct mammary gland-specific expression. Promoter elements of the murine whey acid protein (mWAP) gene were used to drive the expression of hPC-cDNA and hPC-genomic transgenes. Transgenic mice with hPC-cDNA and hPC-genomic sequences gave expression levels of 11 +/- 4 micrograms rhPC/ml of milk and 895 +/- 21 micrograms rhPC/ml of milk, respectively. Transgenic pigs with hPC-cDNA and hPC-genomic sequences gave expression levels of 100 to 500 micrograms rhPC/ml of milk and 800 to 2000 micrograms rhPC/ml of milk, respectively. A monoclonal antibody (7D7B10-mAb) that binds an epitope in the gla domain of hPC in the absence of calcium was used to study the conformational behavior of immunopurified rhPC. Immunopurified rhPC from lower expressing mice and pigs gave a calcium-dependent binding inhibition by 7D7B10-mAb similar to that of hPC. Immunopurified rhPC from higher expressing mice and pigs gave a less calcium-dependent response. This study suggests that a rate limitation in gamma-carboxylation by the mammary gland occurs at expression levels about > 20 micrograms/ml in mice and > 500 micrograms/ml in pigs.
Annals of the New York Academy of Sciences 05/1996; 782:87-96. · 4.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: The similar biological activity of rhPC and hPC indicates that porcine mammary gland can perform many of the processing reactions necessary for recombinant synthesis of complex human proteins and produce them at levels suitable for industrial bioreactor applications. The health of the transgenic pigs appeared unaffected by the expression of high levels of the heterologous protein. We suggest that one of the advantages of using the mammary gland as a bioreactor appears to be the high cell density relative to that of cell culture.
Annals of the New York Academy of Sciences 06/1994; 721:218-33. · 4.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: Endometrial tissue was collected by biopsy from mature Holstein cows either on d 0 (estrus) or on d 9, 14, or 18 of the estrous cycle to determine the effects of day of the cycle, uterine horn, and in vitro progesterone on endometrial protein secretion. Tissue was incubated for 24 h in supplemented media containing 14C amino acids and either 0, 4.7, or 47 ng of progesterone/ml. Media were analyzed for total protein, radiolabeled protein, and profile of protein released during incubation. Endometrial tissue at d 0 released more protein than did tissue collected on all other days. Radiolabeled proteins were greater on d 0 and 18 than on d 9 and 14. Endometrium from the uterine horn contralateral to the corpus luteum released more radiolabeled protein than endometrium from the uterine horn ipsilateral to the corpus luteum. Seventeen protein bands were identified by electrophoresis. Proximity of the uterine horn to the site of ovulation affected the distribution of specific bands 21,400, 55,000, 74,600, and 88,100 molecular weight. The proportion of released proteins represented by proteins of molecular weights 12,700, 19,100, 21,400, 32,000, and 66,500 was affected either by day of the estrous cycle, proximity of uterine horn to the site of ovulation, or progesterone concentration. The results show that day of the estrous cycle and uterine horn not only alter overall endometrial protein secretion and synthetic activity but also have specific effects on distribution of individual proteins.
Journal of Dairy Science 09/1992; 75(8):2112-8. · 2.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: Crossbred gilts and sows (n=116) were used for the collection of 1-cell zygotes for DNA microinjection and transfer. Retrospectively, estrus synchronization and superovulation schemes were evaluated to assess practicality for zygote collection. Four synchronization and superovulation procedures were used: 1) sows were observed for natural estrous behavior; 1000 IU human chorionic gonadotrophin (hCG) was administered at the onset of estrus (NAT); 2) cyclic gilts were synchronized with 17.6 mg altrenogest (ALT)/day for 15 to 19 days followed by superovulation with 1500 IU pregnant mares serum gonadotropin (PMSG) and 500 IU hCG (LALT); 3) gilts between 11 and 16 days of the estrous cycle received 17.6 mg ALT for 5 to 9 days and PMSG and hCG were used to induce superovulation (SALT); and 4) precocious ovulation was induced in prepubertal gilts with PMSG and hCG (PRE). A total of 505 DNA microinjected embryos transferred into 17 recipients produced 7 litters and 50 piglets, of which 8 were transgenic. The NAT sows had less (P < 0.05) ovarian activity than gilts synchronized and superovulated by all the other procedures. Synchronization treatments with PMSG did not differ (P > 0.05) in the number of corpora hemorrhagica or unovulated follicles, but SALT and PRE treaments had higher ovulation rates than LALT (24.7 +/- 2.9, 24.3 +/- 1.8 vs 11.6 +/- 2.7 ovulations; X +/- SEM). The SALT and PRE treatments yielded 12.3 +/- 2.6 and 17.7 +/- 1.7 zygotes. Successful transgenesis was accomplished with SALT and PRE procedures for estrus synchronization and superovulation.
[show abstract][hide abstract] ABSTRACT: The effect of pronuclear microinjection of DNA and culture in excised mouse oviducts on the development of porcine zygotes was assessed in this study. Precocious ovulation was induced in prepubertal gilts with pregnant mare's serum gonadotrophin and hCG. Zygotes received either pronuclear microinjection of buffer alone, buffer containing a DNA construct, or no microinjection. Zygotes were cultured in vitro in either modified Krebs-Ringer bicarbonate medium (KRB) for 144 h or in mouse oviduct (MO) explant culture with KRB for 48, 72, 96, or 120 h. Pronuclear microinjection of DNA resulted in a lower (P less than .05) cleavage index (CI) than did buffer or no microinjection (CI 2.16 +/- .10 vs 2.80 +/- .13 and 2.93 +/- .10). The CI loss was greatest for DNA-injected zygotes at the two-cell stage of development. Coculture of zygotes in MO resulted in a higher CI (P less than .01) than did culture in KRB. Culture in MO for 72 h was the most beneficial system compared with MO for 48, 96, or 120 h (P less than .05; CI 3.25 +/- .12 vs 2.66 +/- .18, 2.79 +/- .14, and 2.40 +/- .14, respectively). Microinjection of DNA, not merely the mechanical procedure, was detrimental to early zygote development and may be the cause of low pregnancy rates.
Journal of Animal Science 08/1992; 70(7):2207-11. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: Uterine body and cornual inseminations (n = 2127) were evaluated over a 3-yr period in Holstein and Jersey cattle. For cornual insemination one-half of each semen dose was deposited approximately 2.5 cm into each uterine horn. Conception rate was lower for cervical insemination (39.4%) than uterine body (48.1%) or cornual (49.3%) inseminations. Pregnancy site distribution was equal for both insemination techniques but cervical insemination resulted in 60% right horn pregnancies. Primary housing, service number, inseminator, lactation number, and sire affected conception rate. Older cows were least fertile (31.4%), second service conception rate was lowest (42.6%), and barn housed cattle had a 39.7% conception rate. Days open was affected by primary housing, service number, sire, site of semen placement, and twinning. Twinning increased days open by 10 d. Optimum time for insemination of lactating cows was between 6 and 12 h after the initial observation of estrus. From this study we conclude that shallow cornual insemination is as effective as uterine body insemination, and conception rate is optimized when estrus is positively assessed.
Journal of Dairy Science 09/1988; 71(8):2278-83. · 2.57 Impact Factor