PLR
Well-known member
Found this while researching mummified fetuses... One thing I found interesting was the # of services compared to pregnacies 743 services and 323 pregnacies...less than half. study done on the isle of Jersey with the native cattle.
the rest of the study can be read here....
http://www.jersey.syd-fyn.dk/earl.htm
84. We now come to a study of Gestation periods and the likeThis investigation is based on the records kept in my own Val Poucin Herd from 1951 to 1961. While one would have liked to work on data from the whole Island, it was impossible to find anything sufficiently comprehensive or reliable. The gestation period is usually given as 281 to 285 days.
85. During those ten years there were 743 services altogether resulting in 323 pregnancies, of which six were twins. Of these 150 were bull calves, 169 heifers. There were 290 normal full term, eight full term but still-born or died within a week, 28 premature or aborted, and three mummufied fæetus. The average gestation period was 278.4 days, with extremes of 248 and 288 days, and 80% of births took place within a week either side of the average, that is to say between 271 and 285 days.
86. We analysed this information further. As between calvings resulting in bull and heifers calves we found no significant difference i the gestation period. As between first calvers, second calvers and so on, there was no significant difference in the average, but that the older the cows get the less likely they are to calve near the due date, the greater the spread about the average. One strange but inexplicable thing though, in cows calving for the sixth time the average gestation period rose to 281.5 days, this however was based only on 16 calvings. It returned to 278 for 7th calvings. No difference was fond between summer and winter calvings.
87. Although the average gestation period remains virtually the same as a cow grows older we wondered if individual cows showed a constant variation, that is to say if one cow was consistently early, and another consistently late. We therefore tabulated all cows with three or more calvings, nine with three calvings, 10 with with four only, 29 with five or more. The result showed no regular pattern.
88. We next turned our attention to the unsuccessful services. These are of course of great importance commercially, for when a cow returns, you keep her for three weeks extre, instead of the cow keeping you. It represents an actual loss of nearly 7% of her productive time in the year We took heifers first, 145 of them. About 60% got into calf at the first service, nearly all after three services, but 12.3 % failed to get into calf at all. One hundred cows were served to get their record calf, 63 stod at first service, 19 at second and 15 failed altogether, and almost identical percentages obtained for 50 cows served to get their third calf. Out of 47 cows served to get their fouth calf 70% stood to first service with only 6.3% not in calf after their third visit to the bull. Frankly it seems to me that these sort of statistics indicate rather how drastic you are about eliminating your shy breeders, and the skill of your vet., than hereditary or environmental factors for sterility.
89. We analysed our data further. Firstly to check an idea that it is more difficult to get a heifer into calf in the winter than in the summer, but found nothing to support this theory.
Secondly, we thought be interesting and useful to see if the heifer that was difficult to get into calf grew up into the cow that was a shy breeder, and conversely that the heifer that got into calf at first service continued throughout her life in the same desirable way. We examined the records of cows which had had six or more calvings to this end, but were disappointed to find no such pattern.
90. Next comparede the breeding records of the different bulls we had used, eight in all, each of which had served more than 30 females (the lowest was actually 29, the highest 122). There was no significant difference between the results got by the different bulls, and as these mere reflect the figures I have given you for the females I will not repeat them.
91. I want through to comment on one bull which I call Bull x, which was the sire of three mummufied calves. Now, as you doubtless know, the mummified calf is due to a lethal double recissive gene. The heterozygous animal appears quite normal, but when at conception, an egg with this lethal gene is fertilized by a sperm with the same lethal gene, the results is double recessive and the embryo dies "in utero" at about five months and instead of being discharged becomes mummified and is retained indefinitely. The double recessive of course can only occur when both bull and acow are carriers of the gene. But if a bull which is a carrier serves a whole lot of cows which are not carries, half those resulting embryos will be heterozygous for this gene.
92. I had always suspected that cows in calf to Bull x abort more frequently than others, and here are the figures which I would suggest confirm that view. This bull served 74 cows abnormal, three being mummufied. Seven other bulls served 398 cows (this excludes daughters of Bull x because one would expect half of them to be herterozygous for the mummified gene) and 247 calves on the farm, and only 20 or 8% were abnormal births. ALthough we were dealing in small numbers in the case of Bull x the result I think deserves further investigation. On those figures the bull that was a carrier was getting 7% less normal births than the others, a serious loss of calves.
93. I would like to report further on the breeding records of Bull x daughters, since half of these would be carriers of the gene. It is of course impossible to identify the individual carrier unless or until she produces a mummufied calf. We had 20 of his daughters, 15 of which calved in the herd, and three or 20% of them were abnormal births. The numbers are again small but the tendency is the same. That is the end of the story so far as I am concerned as I eliminated all potential carriers of the Mummified Fætus gene from my herd as soon as possible.
94. Mummified Foetus is not common on the Island and is not of course the only hereditary defect in the Jersey breed. Indeed, every breed has its quota. Some years ago untershot jaws got into the news in a rather big way. Nowadays they are hardly ever seen. Certainly on the Island this defect does not prevent the animal concerned from feeding normally on the fairly long pasture, though in the countries with bare, shor pastures it might obviously do so. The procedure in connection with all defects is that the Herd Book Examiners in their tours of the Island, are instructed to watch out for any, and report back. Doubtless the Vets. also use their influence and advice to keep such things in check.
95. Probably though, the biggest problems that the Farmer on the Island has to cope with are Milk Fever and Acetona emia and infertility not caused by infections. Unfortunately though I cannot give you any statistical data as to their incidence, nor voice an opinion as to whether they are due to breeding, feeding or the stress factor.
96. As to the other common diseases, I can almost say "We have not any". Bovine Tuberculosis was eradicated about 1860, and there is a vigorous system of testing constantly in operation. Any animal moved from one farm to another or for export has to be tested before moving, and only occasional reactors have turned up since. It is perhaps worth pointing out that there are no cattle markets on the Island. In England these especially are the means by which infectious diseases are so easily spread all over the country and make it so difficult to enforce control. In Jersey, cattle are sold individually or at Farm Auction Sales.
97. Contagious Abortion, Brucellosis or Banks Disease was eradicated by slaughter between 1930 and 1938. Only 128 animals were in fact destroyed. I am told that in England a theory is being followed up that Brucellosis in cattle is associated with Slipped Discs and lower back pain in man.
98. Vibrio Foetus and Trichomaniasis are never known to have occurred on the Island, yet strangely enough they do in Guernsey, and are responsbile for the setting up of an A.1 Station in that Island.
99. Johnnes Disease does exist though it only occurred on three farms in 1962 and it is hoped that by a slaughter policy that this too has been eradicated.
the rest of the study can be read here....
http://www.jersey.syd-fyn.dk/earl.htm
84. We now come to a study of Gestation periods and the likeThis investigation is based on the records kept in my own Val Poucin Herd from 1951 to 1961. While one would have liked to work on data from the whole Island, it was impossible to find anything sufficiently comprehensive or reliable. The gestation period is usually given as 281 to 285 days.
85. During those ten years there were 743 services altogether resulting in 323 pregnancies, of which six were twins. Of these 150 were bull calves, 169 heifers. There were 290 normal full term, eight full term but still-born or died within a week, 28 premature or aborted, and three mummufied fæetus. The average gestation period was 278.4 days, with extremes of 248 and 288 days, and 80% of births took place within a week either side of the average, that is to say between 271 and 285 days.
86. We analysed this information further. As between calvings resulting in bull and heifers calves we found no significant difference i the gestation period. As between first calvers, second calvers and so on, there was no significant difference in the average, but that the older the cows get the less likely they are to calve near the due date, the greater the spread about the average. One strange but inexplicable thing though, in cows calving for the sixth time the average gestation period rose to 281.5 days, this however was based only on 16 calvings. It returned to 278 for 7th calvings. No difference was fond between summer and winter calvings.
87. Although the average gestation period remains virtually the same as a cow grows older we wondered if individual cows showed a constant variation, that is to say if one cow was consistently early, and another consistently late. We therefore tabulated all cows with three or more calvings, nine with three calvings, 10 with with four only, 29 with five or more. The result showed no regular pattern.
88. We next turned our attention to the unsuccessful services. These are of course of great importance commercially, for when a cow returns, you keep her for three weeks extre, instead of the cow keeping you. It represents an actual loss of nearly 7% of her productive time in the year We took heifers first, 145 of them. About 60% got into calf at the first service, nearly all after three services, but 12.3 % failed to get into calf at all. One hundred cows were served to get their record calf, 63 stod at first service, 19 at second and 15 failed altogether, and almost identical percentages obtained for 50 cows served to get their third calf. Out of 47 cows served to get their fouth calf 70% stood to first service with only 6.3% not in calf after their third visit to the bull. Frankly it seems to me that these sort of statistics indicate rather how drastic you are about eliminating your shy breeders, and the skill of your vet., than hereditary or environmental factors for sterility.
89. We analysed our data further. Firstly to check an idea that it is more difficult to get a heifer into calf in the winter than in the summer, but found nothing to support this theory.
Secondly, we thought be interesting and useful to see if the heifer that was difficult to get into calf grew up into the cow that was a shy breeder, and conversely that the heifer that got into calf at first service continued throughout her life in the same desirable way. We examined the records of cows which had had six or more calvings to this end, but were disappointed to find no such pattern.
90. Next comparede the breeding records of the different bulls we had used, eight in all, each of which had served more than 30 females (the lowest was actually 29, the highest 122). There was no significant difference between the results got by the different bulls, and as these mere reflect the figures I have given you for the females I will not repeat them.
91. I want through to comment on one bull which I call Bull x, which was the sire of three mummufied calves. Now, as you doubtless know, the mummified calf is due to a lethal double recissive gene. The heterozygous animal appears quite normal, but when at conception, an egg with this lethal gene is fertilized by a sperm with the same lethal gene, the results is double recessive and the embryo dies "in utero" at about five months and instead of being discharged becomes mummified and is retained indefinitely. The double recessive of course can only occur when both bull and acow are carriers of the gene. But if a bull which is a carrier serves a whole lot of cows which are not carries, half those resulting embryos will be heterozygous for this gene.
92. I had always suspected that cows in calf to Bull x abort more frequently than others, and here are the figures which I would suggest confirm that view. This bull served 74 cows abnormal, three being mummufied. Seven other bulls served 398 cows (this excludes daughters of Bull x because one would expect half of them to be herterozygous for the mummified gene) and 247 calves on the farm, and only 20 or 8% were abnormal births. ALthough we were dealing in small numbers in the case of Bull x the result I think deserves further investigation. On those figures the bull that was a carrier was getting 7% less normal births than the others, a serious loss of calves.
93. I would like to report further on the breeding records of Bull x daughters, since half of these would be carriers of the gene. It is of course impossible to identify the individual carrier unless or until she produces a mummufied calf. We had 20 of his daughters, 15 of which calved in the herd, and three or 20% of them were abnormal births. The numbers are again small but the tendency is the same. That is the end of the story so far as I am concerned as I eliminated all potential carriers of the Mummified Fætus gene from my herd as soon as possible.
94. Mummified Foetus is not common on the Island and is not of course the only hereditary defect in the Jersey breed. Indeed, every breed has its quota. Some years ago untershot jaws got into the news in a rather big way. Nowadays they are hardly ever seen. Certainly on the Island this defect does not prevent the animal concerned from feeding normally on the fairly long pasture, though in the countries with bare, shor pastures it might obviously do so. The procedure in connection with all defects is that the Herd Book Examiners in their tours of the Island, are instructed to watch out for any, and report back. Doubtless the Vets. also use their influence and advice to keep such things in check.
95. Probably though, the biggest problems that the Farmer on the Island has to cope with are Milk Fever and Acetona emia and infertility not caused by infections. Unfortunately though I cannot give you any statistical data as to their incidence, nor voice an opinion as to whether they are due to breeding, feeding or the stress factor.
96. As to the other common diseases, I can almost say "We have not any". Bovine Tuberculosis was eradicated about 1860, and there is a vigorous system of testing constantly in operation. Any animal moved from one farm to another or for export has to be tested before moving, and only occasional reactors have turned up since. It is perhaps worth pointing out that there are no cattle markets on the Island. In England these especially are the means by which infectious diseases are so easily spread all over the country and make it so difficult to enforce control. In Jersey, cattle are sold individually or at Farm Auction Sales.
97. Contagious Abortion, Brucellosis or Banks Disease was eradicated by slaughter between 1930 and 1938. Only 128 animals were in fact destroyed. I am told that in England a theory is being followed up that Brucellosis in cattle is associated with Slipped Discs and lower back pain in man.
98. Vibrio Foetus and Trichomaniasis are never known to have occurred on the Island, yet strangely enough they do in Guernsey, and are responsbile for the setting up of an A.1 Station in that Island.
99. Johnnes Disease does exist though it only occurred on three farms in 1962 and it is hoped that by a slaughter policy that this too has been eradicated.
