Br. vet.
J. (1977), 133. 33
THE VOLUME AND COMPOSITION OF AMNIOTIC AND ALLANTOIC FLUID IN GOAT X SHEEP HYBRID CONCEPTUSES By P. T.
MCGOVERN
Department oj Anatomy, Royal Veterinary College, London, NWI oTU SUMMARY
The volume and composition offoetal fluids in goat and goat X sheep hybrid conceptuses of 35 to 43 days gestational age were determined. The mean amniotic fluid volume in the hybrid conceptuses (12·6 ± 1.48 ml) was significantly lower than that in the goat conceptuses (18·2 ± 2·43 ml) ; the mean allantoic fluid volume in the hybrid conceptuses (173.0 ± 19.05 ml) was significantly higher than that in goat conceptuses (58.4 ± 4.48 ml). Compared to the values for the goat, the allantoic Na + concentration was higher and the allantoic urea concentration was lower in the hybrid conceptuses. Treatment of pregnant females with progesterone at a dose rate known to maintain allantoic fluid at a normal level in goat conceptuses in ovariectomized goats did not reduce allantoic fluid volume in the hybrid conceptuses, a nd had no apparent effect on the survival of the hybrid embryos. INTRODUCTION
The observations presented here on volume and composition of foetal fluids in goat and goat X sheep hybrid conceptuses, are based on data obtained on goats examined post mortem during the course of experiments extending over several breeding seasons. The observations were made with a view to obtaining further information concerning the increase in allantoic fluid in h ybrid conceptuses. In investigations into the death of the goat X sheep hybrid embryo, Alexander, Williams & Bailey (1967) noted that the volume of allantoic fluid in hybrid conceptuses was abnormally large; and Hancock, McGovern & Stamp (1968) found that uteri from goats carrying hybrid embryos were heavier than uteri containing normal goat embryos, the excess weight being attributed to an increase in the volume of foetal fluid. In view of the apparent relationship between progesterone and allantoic fluid volume in both sheep (Alexander & Williams, 1966, 1968) and goats (McGovern, 1976), it was also decided to examine the possibility that the volume of allantoic fluid in the hybrid conceptus could be regulated by administration of the hormone to pregnant goats. The opportunity was also taken to see if the
34
BRITISH VETERINARY JOURNAL, 133,
I
progesterone treatment would extend the survival of the hybrid embryo beyond the usual six-week period (see Hancock, 1964), although present indications are that it is an immunological rather than hormonal incompatability which is responsible for the death of the goat X sheep hybrid embryo (Hancock et al. , 1968 ; Dent, McGovern & Hancock, 1971 a, b; McGovern, 1973). MATERIALS AND METHODS
Observations were made on conceptuses obtained from 23 crossbred goats examined post mortem between day 35 and day 43 of pregnancy in connection with other experiments. None of the animals received any experimental treatment up to the time of slaughter. Measurements of fluid volume were made on 15 goat conceptuses from eight goats, and on 22 goat X sheep hybrid conceptuses from 15 goats. Samples of amniotic and allantoic fluid were obtained for analysis from six goat and nine hybrid conceptuses from three and six goats respectively. The procedures used for sampling, storage and analysis of the fluids were the same as those described previously (McGovern, 1976). Three goats which had been inseminated with sheep semen and had failed to return to service were treated with 40 mg progesterone (Intervet Laboratories Ltd.) per day, given by intramuscular injection. Treatment was begun on day 25 of pregnancy and was continued to day 42 when the animals were examined post mortem. An additional six goats which had been inseminated with sheep semen were treated with daily intramuscular injections of 10, 20 or 40 mg progesterone ('Protormone'; Burroughs Wellcome Ltd.) from day 25 until killed between day 53 and day 56 of pregnancy. RESULTS
The findings on the untreated animals showed that the mean volume of amniotic fluid in the hybrid conceptuses (12·6 ± 1.48 ml) was significantly (P = 0·05) lower than that in the goat conceptuses (18·2 ± 2·43 ml). Differences in allantoic fluid volume were more marked. The mean volume of allantoic fluid in the hybrid conceptuses (173.0 ± 19.05 ml) was considerably greater (P < 0·001) than that in the goat conceptuses (58.4 ± 4.48 ml). The mean values for Na +, K +, CI-, urea and total protein concentration, and for osmolality of the foetal fluids are shown in Table 1. The composition of amniotic fluid in goat and goat X sheep hybrid conceptuses was similar, but differences were evident in the composition of the allantoic fluids. The mean Na + concentration in the hybrid conceptuses was significantly higher than that in the goat conceptuses (P < 0·001); and the mean urea concentration in the hybrid conceptuses was significantly lower than that of the goat conceptuses (P < 0·05). Two of the three progesterone-treated goats examined post mortem on day 42 of pregnancy were each found to be carrying a single embryo. The volumes of amniotic fluid present were 18 and 25 ml, and the volumes of allantoic fluid were 267 and 273 ml. The values for Na +, K +, Cl-, urea and total protein concentration, and for osmolality of the fluids were very close to the mean
COMPOSITION OF FOETAL FLUIDS
35
TABLE I THE MEAN VALUES (± SE ) FOR VOLU ME, NA +, K +, CL -, UREA AND TOTAL PROTEIN CONCENTRATION, AND OSMOLALITY OF THE FOETAL FLUIDS OF GOAT AND GOAT X SHEEP HYBRID CONCEPTUSES OF 35 TO 43 DAYS GESTATIONAL AGE
Amniotic fluid Goat Volume (ml) Na + (mEq/l) K+ (mEq/l) CI (mEq/l) Urea (mg/lOo ml) Total protein (g/ 100 ml) Osmolality (m,osm,/kg)
Allantoic fluid
Hybrid
18'2
±
2'43
12,6
±
1'48
12 7'5
±
3' 22
133'7
±
2' 14
11'2
±
1'02
9'0
±
0,87
116'7
±
4'13
119'0
±
31,8
±
1,68
33 '4
±
J. (1977), 133. 33
THE VOLUME AND COMPOSITION OF AMNIOTIC AND ALLANTOIC FLUID IN GOAT X SHEEP HYBRID CONCEPTUSES By P. T.
MCGOVERN
Department oj Anatomy, Royal Veterinary College, London, NWI oTU SUMMARY
The volume and composition offoetal fluids in goat and goat X sheep hybrid conceptuses of 35 to 43 days gestational age were determined. The mean amniotic fluid volume in the hybrid conceptuses (12·6 ± 1.48 ml) was significantly lower than that in the goat conceptuses (18·2 ± 2·43 ml) ; the mean allantoic fluid volume in the hybrid conceptuses (173.0 ± 19.05 ml) was significantly higher than that in goat conceptuses (58.4 ± 4.48 ml). Compared to the values for the goat, the allantoic Na + concentration was higher and the allantoic urea concentration was lower in the hybrid conceptuses. Treatment of pregnant females with progesterone at a dose rate known to maintain allantoic fluid at a normal level in goat conceptuses in ovariectomized goats did not reduce allantoic fluid volume in the hybrid conceptuses, a nd had no apparent effect on the survival of the hybrid embryos. INTRODUCTION
The observations presented here on volume and composition of foetal fluids in goat and goat X sheep hybrid conceptuses, are based on data obtained on goats examined post mortem during the course of experiments extending over several breeding seasons. The observations were made with a view to obtaining further information concerning the increase in allantoic fluid in h ybrid conceptuses. In investigations into the death of the goat X sheep hybrid embryo, Alexander, Williams & Bailey (1967) noted that the volume of allantoic fluid in hybrid conceptuses was abnormally large; and Hancock, McGovern & Stamp (1968) found that uteri from goats carrying hybrid embryos were heavier than uteri containing normal goat embryos, the excess weight being attributed to an increase in the volume of foetal fluid. In view of the apparent relationship between progesterone and allantoic fluid volume in both sheep (Alexander & Williams, 1966, 1968) and goats (McGovern, 1976), it was also decided to examine the possibility that the volume of allantoic fluid in the hybrid conceptus could be regulated by administration of the hormone to pregnant goats. The opportunity was also taken to see if the
34
BRITISH VETERINARY JOURNAL, 133,
I
progesterone treatment would extend the survival of the hybrid embryo beyond the usual six-week period (see Hancock, 1964), although present indications are that it is an immunological rather than hormonal incompatability which is responsible for the death of the goat X sheep hybrid embryo (Hancock et al. , 1968 ; Dent, McGovern & Hancock, 1971 a, b; McGovern, 1973). MATERIALS AND METHODS
Observations were made on conceptuses obtained from 23 crossbred goats examined post mortem between day 35 and day 43 of pregnancy in connection with other experiments. None of the animals received any experimental treatment up to the time of slaughter. Measurements of fluid volume were made on 15 goat conceptuses from eight goats, and on 22 goat X sheep hybrid conceptuses from 15 goats. Samples of amniotic and allantoic fluid were obtained for analysis from six goat and nine hybrid conceptuses from three and six goats respectively. The procedures used for sampling, storage and analysis of the fluids were the same as those described previously (McGovern, 1976). Three goats which had been inseminated with sheep semen and had failed to return to service were treated with 40 mg progesterone (Intervet Laboratories Ltd.) per day, given by intramuscular injection. Treatment was begun on day 25 of pregnancy and was continued to day 42 when the animals were examined post mortem. An additional six goats which had been inseminated with sheep semen were treated with daily intramuscular injections of 10, 20 or 40 mg progesterone ('Protormone'; Burroughs Wellcome Ltd.) from day 25 until killed between day 53 and day 56 of pregnancy. RESULTS
The findings on the untreated animals showed that the mean volume of amniotic fluid in the hybrid conceptuses (12·6 ± 1.48 ml) was significantly (P = 0·05) lower than that in the goat conceptuses (18·2 ± 2·43 ml). Differences in allantoic fluid volume were more marked. The mean volume of allantoic fluid in the hybrid conceptuses (173.0 ± 19.05 ml) was considerably greater (P < 0·001) than that in the goat conceptuses (58.4 ± 4.48 ml). The mean values for Na +, K +, CI-, urea and total protein concentration, and for osmolality of the foetal fluids are shown in Table 1. The composition of amniotic fluid in goat and goat X sheep hybrid conceptuses was similar, but differences were evident in the composition of the allantoic fluids. The mean Na + concentration in the hybrid conceptuses was significantly higher than that in the goat conceptuses (P < 0·001); and the mean urea concentration in the hybrid conceptuses was significantly lower than that of the goat conceptuses (P < 0·05). Two of the three progesterone-treated goats examined post mortem on day 42 of pregnancy were each found to be carrying a single embryo. The volumes of amniotic fluid present were 18 and 25 ml, and the volumes of allantoic fluid were 267 and 273 ml. The values for Na +, K +, Cl-, urea and total protein concentration, and for osmolality of the fluids were very close to the mean
COMPOSITION OF FOETAL FLUIDS
35
TABLE I THE MEAN VALUES (± SE ) FOR VOLU ME, NA +, K +, CL -, UREA AND TOTAL PROTEIN CONCENTRATION, AND OSMOLALITY OF THE FOETAL FLUIDS OF GOAT AND GOAT X SHEEP HYBRID CONCEPTUSES OF 35 TO 43 DAYS GESTATIONAL AGE
Amniotic fluid Goat Volume (ml) Na + (mEq/l) K+ (mEq/l) CI (mEq/l) Urea (mg/lOo ml) Total protein (g/ 100 ml) Osmolality (m,osm,/kg)
Allantoic fluid
Hybrid
18'2
±
2'43
12,6
±
1'48
12 7'5
±
3' 22
133'7
±
2' 14
11'2
±
1'02
9'0
±
0,87
116'7
±
4'13
119'0
±
31,8
±
1,68
33 '4
±
