Trop Anim Health Prod (2006) 38: 85–92
DOI 10.1007/s11250-006-4249-z
O R I G I NA L A RT I C L E
Radioimmunoassay of milk progesterone as a tool forfertility control in smallholder dairy farmsM. Shamsuddin · M.M.U. Bhuiyan · P.K. Chanda ·M.G.S. Alam · D. Galloway
Accepted: 19 August 2005C© Springer 2006
Abstract This study focused on the use of radioim-
munoassay of progesterone in milk for the diagnosis of
post-partum ovarian cyclicity and accurate detection
of oestrus and non-pregnancy in cows in the artificial
insemination (AI) programme in Bangladesh. In In-
vestigation 1, milk samples were collected on day 0
(day of AI), day 9–13 and day 21–24 from 444 milk-
ing cows of various breeds presented for the first post-
partum insemination by 413 farmers living at 182 vil-
lages/regions in Mymensingh District from 6 AI cen-
tres and sub-centres. Each cow was then examined three
times after each AI until it stopped returning to oestrus.
Sixty to 90 days after the last AI, the cows were exam-
ined per rectum to confirm the pregnancy. Milk pro-
gesterone data on day 21–24 contributed to a clear di-
agnosis with respect to non-pregnancy in 100% cows,
indicating a possible use of this progesterone assay for
identifying non-pregnant cows in AI programmes. In
Investigation 2, milk progesterone was monitored two
times in a month with a 10-day interval in 88 cows.
The samples were taken between 10 days after calving
and the first detected oestrus, followed by two more
M. Shamsuddin · M.M.U. Bhuiyan (�)· P.K. Chanda ·M.G.S. AlamDepartment of Surgery and Obstetrics, Faculty ofVeterinary Science, Bangladesh Agricultural University,Mymensingh, Bangladeshe-mail: [emailprotected]
D. GallowayDepartment of Veterinary Science, University ofMelbourne, Werribee, Australia
samples 10 days apart. The proportion of cows accu-
rately detected in oestrus was 30%. Another 30% were
stated to be in oestrus when they were not (false pos-
itive) and 40% were not detected when they were in
oestrus (false negative). The mean intervals between
calving and oestrus and between calving luteal activity
were 40 to 362 days (median = 120, n = 82) and 34
to 398 (median = 111, n = 64) days, respectively. The
body condition scores at calving and at the initiation
of luteal activity influenced the interval between calv-
ing and luteal activity (p < 0.05). Cows suckled twice
daily initiated luteal activity earlier than their counter-
parts suckled several times daily (p < 0.05). Determi-
nation of progesterone in milk on day 21–24 is a good
means for detecting non-pregnant cows.
Keywords Cattle · Progesterone · Non-pregnancy
diagnosis · Radioimmunoassay · Smallholder dairy
farm
AbbreviationsAIDA artificial insemination data analysis
BCS body condition score
RIA radioimmunoassay
FAO Food and Agriculture Organization
IAEA International Atomic Energy Agency
Introduction
Many farms in Bangladesh are so small that only one
cow can be kept. Cows are tethered in a stable or
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86 Trop Anim Health Prod (2006) 38: 85–92
on available grazing land. They are used for draught
work as well as milk production and weaning is not
controlled. These management practices promote the
occurrence of post-partum anoestrus and limit be-
havioural manifestations of oestrus. Most Bos indicuscows show weak oestrus signs for a shorter duration
than Bos taurus cows. Detection of oestrus and of the re-
turn to oestrus after unsuccessful artificial insemination
(AI) is clearly difficult under such conditions and inef-
ficiencies have been documented (Shamsuddin, 1995).
Extended post-partum anoestrus, conception failure
and embryonic mortality were claimed to be a major
constraint limiting the reproductive efficiency in zebu
and crossbred cows (Alejandrino et al., 1999).
Traditionally, pregnancy diagnosis is not carried
out as part of the AI programmes. Veterinary services
are not always available. There is therefore is a need
to introduce other methods to determine the status
of cows with respect to cyclicity and pregnancy in
association with AI programmes. Analysis of three
milk, plasma or serum samples on day 0 (the day
of AI), day 10–12 and day 22–24 after AI has been
shown elsewhere to be an effective tool for monitoring
the efficiency of oestrus detection, cyclicity of the cow
and quality of AI services (Cai et al., 2001). Usually,
sampling of milk is more convenient than sampling
of plasma and serum. Milk progesterone level on the
day of AI retrospectively reflects accuracy of oestrus
detection (Nebel et al., 1987). There are reports show-
ing high accuracy of non-pregnancy diagnosis based
on milk progesterone concentrations on day 22–24
after AI in large commercial dairy farms (Kaul and
Prakash, 1994). However, information on the use of
such techniques in smallholder cattle farms is limited.
The aim of the present work was to use the radioim-
munoassay (RIA) of progesterone in milk as a diag-
nostic tool to determine the status of cows in AI pro-
grammes with respect to cyclicity and pregnancy. This
could lead to use of milk progesterone RIA as a tool
for identifying non-pregnant cows as a service to AI
programmes.
Materials and methods
The investigation included 413 farmers living in 182
villages/regions in Mymensingh District, one of the 64
administrative units of Bangladesh. Mymensingh has a
medium-high type land with soil pH varying from 5.5
to 7.5 and is a part of Bangladesh usually unaffected
by floods. A 50-year meteorological data summary in-
dicated that the minimum and maximum temperatures
were between 11.7 and 25.6◦C and between 24.8 and
32.9◦C, respectively. The humidity and rainfall varied
from 67 to 87% and from 8 to 395 mm, respectively.
Crop production is the main source of livelihood. Most
people generate only a low income. The farmers’ land
totalled between 0 and 40 (median 0.6) hectares with 1–
70 (median 2.0) breedable cows. Dairying is mostly of
a subsistence type. Most of the cows were Bos indicusand others were crosses of Bos indicus with Holstein-
Friesian and a mixture of indigenous zebus. The cows
were milked 1 to 2 (median 1.0) times per day with their
calves at foot. Calves survived on residual milk after
the hand milking was completed. Controlled weaning
was not practised; therefore, the time of spontaneous
weaning was recorded. The cows were fed on rice straw,
cut-and-carry grass and milling by-product as concen-
trate (rice polish, wheat bran and various oil cakes) with
limited grazing on roadside and community land. The
field work took place between August 1995 and June
1998.
Investigation 1. Milk progesterone RIA in
diagnosing non-pregnancy and quality of AI
services
Milking cows presented for first post-partum insemi-
nation were included in this study. For analysis of pro-
gesterone concentration, milk samples were collected
in vials containing sodium azide tablets (8 mg; Merk,
Darmstadt, Germany) as preservative. The day 0 (day of
insemination) milk samples were collected by the AI
technician immediately after AI. Usually poor farm-
ers from the extensive farms bring the cows to the AI
centres, and on commercial farms or farms owned by
the rich farmers the AI operators visit the farms. If
AI operators were called to the farms, they arrived
within two hours. The research personnel picked up
the samples within 2 days after collection. The day
9–13 and day 21–24 milk samples were collected by
research personnel directly from the cow at a farm visit.
The milk samples were centrifuged and skimmed milk
was separated and stored at −20◦C until analysed. Pro-
gesterone concentration in milk was determined using
solid-phase radioimmunoassay (RIA) kits supplied by
the FAO/IAEA, Vienna, Austria. The intra-assay coef-
ficient of variation (CV) with internal quality control
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Trop Anim Health Prod (2006) 38: 85–92 87
(IQC) samples varied from 8.0% to 15.6% (10 assays,
each with 10 replicates) and the inter-assay CVs were
16.6% and 18.4% for beginning and end IQC samples,
respectively (number of assays = 10). Between day 60
and day 90 after the last recorded AI, all cows were
examined per rectum for confirmation of pregnancy; a
milk sample was always collected immediately before
rectal palpation if the cow was not dry at that time. The
farmers did not pay for the progesterone testing and
the economic benefit obtained by the farmers was not
estimated.
Investigation 2. Milk progesterone RIA in
monitoring of post-partum cyclicity and accuracy
of oestrus detection in cows
Eighty-eight cows on 58 farms were registered within
1 week after calving and relevant information with
regard to the farm and cattle was recorded. For indi-
vidual cows, information was collected on age, breed,
parity, last calving date, body weight and body condi-
tion score (BCS) at calving, occurrence of oestrus, and
the occurrence of any post-parturient disorders. Cows
that required major assistance during parturition and/or
that were diagnosed with periparturient disorders such
as retained placenta, puerperal metritis, post-partum
haemorrhage, prolapse of the genital tract or milk fever
were not included in the investigation. We requested the
farmers to report the date and signs of oestrus, but there
was no discussion between the project personnel and
farmers on the signs of oestrus and their relevance to
conception.
The research personnel collected milk samples from
individual cows twice a month, with a 10-day interval,
between 10 days post partum and the first report of
oestrus by the farmer. Two more samples were col-
lected, at 10 days’ interval, after the occurrence of
oestrus. During milk sampling, the research personnel
scored the cow for body condition (1–5 scales with 0.5
fractions), measured its body weight, asked the farmer
about the occurrence of oestrus and examined the cow
for the presence of any dry or fresh discharge adhering
to the perineum. The milk samples were processed as
in Investigation 1.
Analysis of the data
The data on milk progesterone concentrations at day 0,
day 9–13 and day 21–24 were compared with the results
of per rectum pregnancy diagnosis. Artificial insemi-
nation data application (AIDA, International Atomic
Energy Agency, Vienna, Austria) was used to record
and analyse the data. Progesterone data based on two
samples (day 0 and day 9–13) were used to examine the
efficiency of oestrus detection. Milk progesterone con-
centration on the day of AI was used to determine the
proportions of AI performed in the luteal phase of the
cow. In Investigation 2, the following model (Goodger
et al., 2001) was used to analyse the data:
INT = μ + b1x1 + b2x2 + b3x3 + b4x4 + b5x5
+ b6x6 + b7x7 + b8x8 + b9x9 + e
where: INT = log of interval between calving and the
first detected luteal activity (days); μ = general mean;
x1 = cattle rearing system (extensive vs intensive); x2
= purpose of rearing cows (dairy vs dairy + draught);
x3 = feeding system (concentrate fed vs no concentrate
fed); x4 = breed of cow (crossbred Friesian, crossbred
Sahiwal, local); x5 = BW at calving (group 1, ≤200 kg;
group 2, 201–250 kg; group 3, 251–300 kg; group 4,
≥301 kg); x6 = BCS at calving (group 1, 1.0–2.0; group
2, 2.5; group 3, 3.0; group 4, 3.5–5.0); x7 = BW at the
first detected luteal activity (group 1, ≤200 kg; group 2,
201–250 kg; group 3, 251–300 kg; group 4, ≥301 kg);
x8 = BCS at the first detected luteal activity (groups 1,
1.0–2.0; group 2, 2.5; group 3, 3.0; group 4 3.5–5.0); x9
= frequency of suckling (once or twice daily vs several
times a day); e = error term.
The data were log-transformed to near normality.
ANOVA was used to test the effect of the accuracy of
oestrus detection on the post-partum interval to oestrus
(false positive cases were deleted). Unless otherwise
indicated, the data are presented as median and range
owing to high individual variations. Only the factors
that tended (p = 0.10) to or significantly (p < 0.05)
influenced the dependent variables are presented in the
figure and tables.
Results
Investigation 1. Milk progesterone RIA in
diagnosing non-pregnancy and quality of AI
services
The cows studied were 4–18 (median 7.4) years old,
their parity ranged from 1 to 12 (median 2), body
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88 Trop Anim Health Prod (2006) 38: 85–92
Table 1 Three-sample milk progesterone data with respect to pregnancy results
Day 0 Day Day Number of
(day of AI) 9–13 21–24 cases (%) Rectal palpation results; interpretation
Lowa Highb High 202 (56.1) Pregnant
Low Intermediatec High 7 (1.9) Pregnant; RIA problem, biological variations
Low High Low 75 (20.8) Non-pregnant; fertilization failure, early embryonic
death, post-AI anoestrus
Low Intermediate Low 7 (1.9) Non-pregnant; fertilization failure, short luteal phase,
RIA problem, biological variation
Intermediate/high Low/intermediate/
high
Low 6 (1.7) Non-pregnant; AI at incorrect time, post-AI anoestrus
Clear interpretation 297 (82.5)
Low High High 27 (7.5) Non-pregnant; late embryonic death (>16 days) luteal
cyst, persistent corpus luteum (CL)
High High High 2 (0.6) Pregnant; AI on pregnant animal
Low Intermediate High 4 (1.1) Non-pregnant; RIA problem, biological variation, late
embryonic death, persistent CL
Low High Intermediate 20 (5.6) Non-pregnant; fertilization failure, late embryonic death
RIA problem, biological variation
Low Low Intermediate 2 (0.6) Non-pregnant; AI in anoestrous cow, RIA problem
Intermediate/high Low/intermediate/
high
Intermediate/
high
8 (2.2) Non-pregnant; AI at incorrect time, luteal cyst,
persistent CL
Total number of observations 360
aLow, <1.0 nmol/L; bHigh, ≥3.0 nmol/L; cIntermediate, 1.0–3.0 nmol/L
weight was from 103 to 480 (median 196) kg, BCS
was from 1 to 5 (median 3) and milk production var-
ied from 0.3 to 16.0 (median 2) litres per day. The
interpretation of progesterone data based on three sam-
ples (day 0, day 9–13 and day 21–24) with respect to
pregnancy results is shown in Table 1. Milk proges-
terone data gave a clear interpretation in 82.5% cows
(n = 360) about their pregnancy status when compar-
ison was made with per rectum pregnancy diagnosis
at day 60–90. None of the 75 cows with a proges-
terone profile of low (<1.0 nmol/L), high (≥3 nmol/L)
and low on day 0, day 9–13 and day 21–24, respec-
tively, were found pregnant at rectal palpation. Twenty-
seven cows (7.5%) had a progesterone profile of low
high and high on day 0, day 9–13 and day 21–24, re-
spectively, but were not pregnant at rectal examina-
tion. Two inseminations were made in pregnant cows.
All cows confirmed pregnant at rectal palpation had
≥3 nmol/L progesterone in skimmed milk at the day
of pregnancy diagnosis. Cows with milk progesterone
level <3 nmol/L were always non-pregnant. Eighty-
one percent of cows (n = 478; including all services)
had a progesterone profile of low and high on day
0 and day 9–13, respectively, indicating AI not per-
formed at luteal phase nor during ovarian acyclicity
(Table 2). Fifty-nine cows (12.3%) received AI at an in-
correct time as evident from a deviant progesterone pro-
file. Twenty-seven of 505 services (5.3%) were made
when the cow had a high to intermediate level of milk
progesterone.
Investigation 2. Milk progesterone RIA in
monitoring of post-partum cyclicity and accuracy
of oestrus detection in cows
The cows studied were 3–15 (median = 6.0) years old
and of parities 1–8 (median = 3.0). At calving they
weighed 160–456 (median 270) kg and BCS was 1.5–
3.5 (median 2.5). The intervals from calving to the first
detected oestrus and to the initiation of luteal activity
were 40–362 (median 115; n = 82) and 34–398 (me-
dian 108, n = 64) days, respectively. Farmers missed
detecting an oestrus (false negative) on 1–3 (median
1.0) occasions post partum. The proportion of cows
accurately detected in oestrus was 30%. Another 30%
were stated to be in oestrus when they were not (false
positive) and 40% were not detected when they were in
oestrus (indicated by one to three progesterone peaks
(≥3 nmol/L) before the cow was identified as being in
oestrus).
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Trop Anim Health Prod (2006) 38: 85–92 89
Table 2 Milk progesteroneprofiles of the artificiallyinseminated cows on the dayof service and on day 9–13with respect to the accuracyof oestrus detection
Day 0 Day Number of
(day of AI) 9–13 cases (%) Interpretation
Lowa Highb 387 (81.0) Progesterone concentration within negative
range on day 0 and within positive range on
day 9–13 indicates an ovulatory cycle –
accurate oestrus detection
Low Low 47 (9.8) Progesterone concentration within negative
range on both days indicates anoestrus,
anovulation, or short luteal phase –
inaccurate oestrus detection
High High 6 (1.3) Progesterone concentration within positive
range on both days indicates AI in pregnant
animals or in animals with luteal cyst –
inaccurate oestrus detection
High Low 6 (1.3) Progesterone concentration within positive
range on day 0 and within negative range
on day 9–13 indicates that AI was
performed during luteal phase – inaccurate
oestrus detection
Total occurrence 478
Total inaccurate oestrus detection 59 (12.3)
aLow =< 1.0 nmol/L;bHigh =≥ 3.0 nmol/LThirty two services (6.7%)were made in cows with anintermediate level of milkprogesterone(1.0–3.0 nmol/L) on day 0,on day 9–13 or on bothoccasions
Fig. 1 Effect of body condition (BCS) at calving (A) and at first luteal phase (B) on the post-partum interval to the initiation of lutealactivity
The post-partum intervals to the initiation of first
luteal activity were examined in these cows. Those with
BCS 3.5 or more at calving needed fewer days to initiate
luteal activity than their counterparts having BCS 3.0
or less (Figure 1A, B; p < 0.05). Cows suckled once
or twice daily required fewer days (median 95, range
34–398; n = 28) than the cows suckled several times a
day (median 127, range 35–279; n = 36) (p < 0.05).
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90 Trop Anim Health Prod (2006) 38: 85–92
The median interval to first post partum oestrus was
prolonged by 33.5 days due to farmers’ inability to
detect the oestrous cows (p < 0.05). The age of the
cows and their parities did not influence the initiation
of luteal activity (p > 0.50). The effects of body weight
at calving, purpose of rearing cows (dairy vs dairy +draught) and breed of cow on the initiation of luteal
activity were not significant (p > 0.10)
Discussion
Milk progesterone data based on three samples (day 0,
day 9–13 and day 21–24) helped in making a clear de-
cision about the pregnancy in 82.5% cows. If only the
non-pregnancy diagnosis is concerned, milk proges-
terone concentration on day 21–24 (day of oestrus =day 0) will give the same results without compromising
the accuracy. Milk progesterone concentration on day
0 and day 9–13 together not only identified inaccurate
oestrus detection but also gave a clear indication of the
cyclical status of the animals. Progesterone concentra-
tion on day 0 can only indicate whether or not AI was
done in a cow with functional luteal tissues in the ovary.
It was clear that cows with less than 3 nmol/L in milk
on day 21–24 were always non-pregnant. Where vet-
erinary services are not available or are too expensive,
milk progesterone concentrations on day 21–24 can be
used to interpret pregnancy results with 100% accuracy
of non-pregnancy diagnosis (Kaul and Prakash, 1994).
It is possible for a RIA laboratory to apply this approach
easily in smallholder dairy farms where heat is not de-
tected by any aids. Farmers’ Knowledge of the non-
pregnancy status of cows by 21–24 days would defi-
nitely help detecting the cows’ return to estrus and en-
able them to be inseminated by 42 days without losing
time until confirmation of pregnancy. Consequently, the
interval from calving to conception would decrease, re-
sulting in economic benefit to the farms even though
the farmer had to wait for another cycle length to get the
cow inseminated. This problem could be minimized if
the non-pregnancy status of cows could be determined
by 19 days and the farmer could be informed about
the result of AI immediately after RIA, resulting in de-
tection of heat by careful observation followed by AI
without wasting time for another cycle. However, at
the moment, owing to transportation and communica-
tion problems, it would take at least 3–4 days for the
milk sample to be analysed and the result sent back
to the farmer, resulting in waiting for another cycle
length.
Failure to detect oestrus (false negative) and false
determination of oestrus (false positive) are common
problems in AI of cows in intensive farming (Smith,
1986; Dawuda et al., 1989; Johnson et al., 1992). False
negative and false–positive categories of oestrus detec-
tion have been found by others to be as high as 30–
50% (Rounsaville et al., 1979; Dawuda et al., 1989;
Johnson et al., 1992) and 17–30% (Smith, 1986), re-
spectively. This can be explained by the fact that in
intensive farming or in small holdings having one cow,
oestrus cannot be detected by primary signs such as
‘standing to be mounted’ as the cows are always tied
up. However, the main weakness affecting the accu-
racy of oestrus detection is that farmers are missing
or misinterpreting or are unaware of secondary signs
of oestrus such as mucus discharge and swollen vulva.
Nevertheless, the false positive oestrus detection was
lower in Investigation 1 (12%) than that in Investigation
2 (30%). In Investigation 1, the cows were recorded at
the AI centres. Firstly, this means that farmers made
a positive decision about the oestrus of the cow. Sec-
ondly, the registration of cows by the AI technicians in
Investigation 1 raises the question whether they made
any selection in favour of good oestrus signs to prove
their good performance. In Investigation 2, to avoid our
frequent visits, some farmers might have made inten-
tional false reports about oestrus. Because cows in the
false-negative category are not inseminated and cows
in the false-positive category are unlikely to become
pregnant in that cycle, resulting in increased calving to
conception interval.
Cows with good body condition at calving and there-
after initiate post-partum cyclicity earlier than those
with poor body condition. This is in agreement with
earlier findings (Bolanos et al., 1998) and indicates the
importance of good nutritional management of preg-
nant cows to cover the negative energy balance due
to growth of the fetus and subsequent milk production
(Claycomb et al., 1996). A positive effect of a high
nutrition plan with restricted suckling on reducing the
calving to conception interval was described by Das
and colleagues (1999). Early initiation of postpartum
cyclicity will reduce the interval from calving to first
service and to conception.
The adverse effects of the duration and frequency
of suckling on the initiation of post-partum cyclicity
as indicated by our results are in accordance with
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Trop Anim Health Prod (2006) 38: 85–92 91
other reports (Williams, 1990). In a different study,
we found an increased interval from calving to first
service and to conception due to frequent suckling
(Shamsuddin et al., 2001). Controlled suckling for a
restricted period favours post-partum reproduction in
cows (Msanga and Bryant, 2003). The results of the
present investigations do not clarify whether prolonged
suckling lengthens the onset of post-partum ovarian
activity or wheather the suckling continues because
the cows do not dry off since they are not pregnant.
However, in commercial dairy farming, controlled
weaning should be practised to identify cows with an
inherent tendency to remain acyclic irrespective of
suckling and nutrition management.
It appears that determination of progesterone in milk
on day 21–24 is a good means of making decisions on
pregnancy by diagnosing the non-pregnant state with
high accuracy. Farmers should have better training in
oestrus detection. The nutritional condition of the cow
at calving and duration and frequency of suckling are,
among others, important determinants of the intervals
to the initiation of ovarian activity.
Acknowledgements
The project was funded by the joint FAO/IAEA divi-
sion, Vienna, Austria (research contract no. 8566/RB).
We thank the Department of Livestock Services of
Bangladesh for giving us access to its AI activities for
the completion of this study.
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92 Trop Anim Health Prod (2006) 38: 85–92
Radioimmunodosage de la progesterone du lait atitre d’outil de controle de la fecondite dans des fer-mes laitieres de petit* cultivateurs
Resume – La presente etude s’est concentree sur l’usage d’unradioimmunodosage de la progesterone dans le lait pour le di-agnostic de la cyclicite ovarienne post-partum, la precision de ladetection de l’œstrus et la non-gravidite chez des vaches dans lecadre d’un programme d’insemination artificielle (AI) entreprisau Bangladesh. Dans l’investigation 1, des echantillons de lait ontete recueillis au Jour 0 (jour de l’AI), aux Jours 9 a 13 et aux Jours21 a 24 de 444 vaches allaitantes de diverses races presentees pourla premiere insemination post partum par 413 cultivateurs vivantdans 182 villages/regions du district de Mymensingh a 6 centreset sous-centres de AI. Chaque vache a ensuite ete examinee troisfois apres chaque AI jusqu’a ce qu’elle cesse d’être fecondable.Soixante a 90 jours apres le dernier AI, les vaches ont ete ex-aminees par le rectum pour confirmer la gravidite. Les donneesde la progesterone du lait aux Jours 21 a 24 ont contribue a undiagnostic irrefutable de non-gravidite chez 100% des vaches,indiquant la possibilite d’utiliser ce dosage de la progesteronepour l’identification des vaches non gravides dans le cadre desprogrammes AI. Dans l’investigation 2, la progesterone du lait aete controlee deux fois en un mois a 10 jours d’intervalle chez 88vaches. Les echantillons ont ete preleves entre 10 jours apres levêlage et le premier oestrus detecte, suivis de deux echantillonsde plus a 10 jours d’intervalle. La proportion des vaches detecteesavec precision en oestrus a ete de 30%. Une autre proportion de30% des vaches a ete declaree être en oestrus alors qu’elles nel’etaient pas (faux positifs) et une proportion de 40% des vachesn’ont pas ete detectees alors qu’elles etaient en oestrus (fauxnegatifs). Les intervalles entre le velage et l’œstrus et l’activiteluteale ont ete de 40 a 362 (valeur mediane = 120, n = 82)et 34 a 398 (valeur mediane = 111, n = 64) jours, respective-ment. Les scores de la condition corporelle (BCS) au velage etau commencement de l’activite luteale ont influence l’intervalleentre le velage et l’activite luteale (p < 0.05). Les vaches teteesdeux fois par jour ont commence une activite luteale plus tot queleurs hom*ologues tetees plusieurs fois par jour (p < 0.05). Ladetermination de la progesterone dans le lait aux Jours 21 a 24est un bon moyen de detection des vaches non gravides.
Radioinmunoanalisis de progesterona en lechecomo herramienta para el control de la fertilidaden pequenas granjas lecheras
Resumen – El presente estudio se centro en la utilizacion de ra-dioinmunoanalisis de progesterona en leche para el diagnosticode la ciclicidad ovarica post-parto, la precision de la detecciondel estro y la ausencia de prenez en vacas en el programa de in-seminacion artificial (IA) de Bangladesh. En la investigacion 1,se recogieron muestras de leche en el dıa 0 (dıa de IA), dıas 9–13y dıas 21–24 a partir de 444 vacas de ordeno de diferentes razaspresentadas para la primera inseminacion post-parto a 6 centrosy subcentros de IA, por 413 granjeros que vivıan en 182 pueb-los/regiones del Distrito de Mymensingh. Cada vaca era luegoexaminada tres veces despues de cada IA hasta que paraba deregresar al estro. Se examino el recto de las vacas, a los 60–90dıas despues de la ultima IA, para confirmar el embarazo. Losdatos de la progesterona en leche en los dıas 21–24 contribuıana un claro diagnostico con respecto a la no prenez en el 100%de las vacas, indicando con ello una posible utilizacion de esteanalisis de progesterona para identificar a las vacas no prenadasen los programas de IA. En la investigacion 2, se monitorizola progesterona de la leche, dos veces al mes con un intervalode 10 dıas, en 88 vacas. Las muestras fueron tomadas entre 10dıas despues del parto y el primer estro detectado, seguidas pordos muestras mas con 10 dıas de diferencia. La proporcion devacas a las que se les detecto con precision el estro fue de un30%. Otro 30% fue declarado estar en estro cuando en realidadno estaban (falso positivo) y a un 40% no se les detecto cuandose hallaban en estro (falso negativo). Los intervalos entre partosy estros, y la actividad luteınica fueron de 40 a 362 (media =120, n = 82) y 34 a 398 (media = 111, n = 64) dıas, respec-tivamente. La puntuacion de la condicion corporal (PCC) en elparto y al inicio de la actividad luteınica influıa en el intervalo en-tre partos y actividad luteınica (p < 0.05). Las vacas que dabande mamar dos veces al dıa iniciaban la actividad luteınica maspronto que sus companeras que daban de mamar varias veces aldıa (p < 0.05). La determinacion de la progesterona en la lecheen los dıas 21–24 es un buen medio para detectar a las vacas noprenadas.
Springer
