AÑO 1, NÚMERO 1, SEPTIEMBRE 2007
Estimados colegas, éste es el primer número de Noticias de Reproducción Bovina,
publicación que tiene como propósito ofrecer información para los Médicos
Veterinarios Zootecnistas que están trabajando en el manejo reproductivo de hatos
bovinos tanto lecheros como de carne. La información contenida proviene de publicaciones científicas
periódicas de alto nivel y también de artículos de difusión técnica escritos por especialistas. Aquí podrán
encontrar los resúmenes y la referencia para la consulta del artículo completo. La selección de la
información está a cargo de los editores y se hace de acuerdo con el criterio de la utilidad práctica de la
misma. El objetivo al iniciar con el primer número es ofrecer una publicación bimestral, la cual llegará
en forma electrónica a los colegas inscritos en nuestras bases de datos y a todos aquellos que nos escriban
solicitándola. Esta es una publicación sin fin de lucro y su único objetivo es ofrecer información actualizada
para mejorar el desempeño de los Veterinarios y con ello contribuir al aumento de la productividad de los
hatos bovinos de nuestro país.
Editores: Dr. Joel Hernández Cerón y MC Alvaro Ortega León
Departamento de Reproducción
Facultad de Medicina Veterinaria y Zootecnia
Universidad Nacional Autónoma de México
Journal of Dairy Science 2007;90:2569–2576
EXPECTED NET PRESENT VALUE OF PURE AND MIXED
SEXED SEMEN ARTIFICIAL INSEMINATION STRATEGIES IN
DAIRY HEIFERS
N. J. Olynk and C. A. Wolf
Sexed semen has been a long-anticipated tool for
dairy farmers to obtain more heifer calves, but
challenges exist for integrating sexed semen into
commercial dairy farm reproduction programs.
The decreased conception rates (CR) experienced
with sexed semen make virgin heifers better
suited for insemination with sexed semen than
lactating dairy cows. This research sought to
identify when various sexed semen breeding
strategies provided higher expected net present
value
(NPV)
than
conventional
artificial
insemination (AI) breeding schemes, indicating
which breeding scheme is advisable under various
scenarios. Budgets were developed to calculate
the expected NPV of various AI breeding
strategies incorporating conventional (non-sexed)
and sexed semen. In the base budgets, heifer and
bull calf values were held constant at $500 and
$110, respectively. The percentage of heifers
expected to be born after breeding with
conventional and sexed semen used was 49.2 and
90%, respectively. Breeding costs per AI were
held constant at $15.00 per AI for conventional
semen and $45.00 per AI for sexed semen of
approximately
the
same
genetic
value.
Conventional semen CR of 58 and 65% were
used, and an AI submission rate was set at 100%.
Breeding strategies with sexed semen were
assessed for breakeven heifer calf values and
sexed semen costs to obtain a NPV equal to that
achieved with conventional semen. Breakeven
heifer calf values for pure sexed semen strategies
with a constant 58 and 65% base CR in which
sexed semen achieved 53% of the base CR are
$732.11 and $664.26, respectively. Breakeven
sexed semen costs per AI of $17.16 and $22.39,
compared with $45.00 per AI, were obtained to
obtain a NPV equal to that obtained with pure
conventional semen for base CR of 58 and 65%,
respectively. The strategy employing purely sexed
semen, with base CR of both 58 and 65%, yielded
a lower NPV than purely conventional semen in all
but the best-case scenario in which sexed semen
provides 90% of the CR of conventional semen.
Other potential advantages of sexed semen that
were not quantified in the scenarios include
biosecurity-related concerns, decreased dystocia
due to increased numbers of heifer calves, and
implications for internal herd growth.
olynknic@msu.edu
Theriogenology 2007;67:1256–1261
CORPUS LUTEUM SIZE AND FUNCTION FOLLOWING
SINGLE AND DOUBLE OVULATIONS IN NON-LACTATING
DAIRY COWS
G.E. Mann, R.S. Robinson, M.G. Hunter
Data was collated from a number of studies on
various aspects of luteal function in non-lactating
dairy cows to allow comparisons to be made
between single and double ovulating animals. In
these studies, estrous cycles had been
synchronized and animals slaughtered on day 5 or
8. The overall incidence of double ovulations was
28.3%. Double ovulation was associated with
smaller individual corpora lutea but no difference
in total weight of luteal tissue or any aspect of
luteal tissue function or plasma concentrations of
progesterone. Furthermore, in a sub set of
animals, there was no difference in preovulatory
follicle characteristics or plasma concentrations of
estradiol around ovulation. These results
demonstrated a high incidence of double ovulation
in non-lactating cows that had no influence on
circulating progesterone concentrations.
george.mann@nottingham.ac.uk
Journal of Dairy Science 2007;90:1477–1485
DIETARY ENERGY SOURCE IN DAIRY COWS IN EARLY
LACTATION: METABOLITES AND METABOLIC HORMONES
A. T. M. van Knegsel, H. van den Brand, E. A. M. Graat, J. Dijkstra,
R. Jorritsma, E. Decuypere, S. Tamminga, and B. Kemp
Negative energy balance-related metabolic
disorders suggest that the balance between
available lipogenic and glucogenic nutrients is
important. The objectives of this study were to
compare the effects of a glucogenic or a lipogenic
diet on liver triacylglycerides (TAG), metabolites,
and metabolic hormones in dairy cows in early
lactation and to relate metabolite concentrations
to the determined energy retention in body mass
(ER). Sixteen dairy cows were fed either a
lipogenic or glucogenic diet from wk 3 prepartum
to wk 9 postpartum (pp) and were housed in
climate respiration chambers from wk 2 to 9 pp.
Diets were isocaloric (net energy basis).
Postpartum, cows fed a lipogenic diet tended to
have higher nonesterified fatty acid concentration
(NEFA; 0.46 ± 0.04 vs. 0.37 ± 0.04 mmol/L) and
lower insulin concentration (4.0 ± 0.5 vs. 5.5 ±
0.6 ± IU/mL). No difference was found in plasma
glucose, β-hydroxybutyrate, insulin-like growth
factor-I, and thyroid hormones. Liver TAG was
equal between both diets in wk −2 and 2 pp. In
wk 4 pp cows fed the glucogenic diet had
numerically lower TAG levels, although there was
no significant dietary effect. Negative relationships
were detected between ER and milk fat and
between ER and NEFA. A positive relationship was
detected between ER and insulin concentration.
Overall, results suggest that insulin plays a
regulating role in altering energy partitioning
between milk and body tissue. Feeding lactating
dairy cows a glucogenic diet decreased
mobilization of body fat compared with a lipogenic
diet. The relative abundance of lipogenic
nutrients, when feeding a more lipogenic diet, is
related to more secretion of lipogenic nutrients in
milk, lower plasma insulin, and higher plasma
NEFA concentration.
Ariette.vanKnegsel@wur.nl
Animal 2007;1:335–346
EFFECT OF CHANGES IN DIET ENERGY DENSITY ON FEED
INTAKE, MILK YIELD AND METABOLIC PARAMETERS IN
DAIRY COWS IN EARLY LACTATION
Theriogenology 2007;67:486–493
EARLY PREGNANCY DIAGNOSIS BY PALPATION PER
VIABILITY IN
DAIRY CATTLE
RECTUM: INFLUENCE ON EMBRYO/FETAL
N. I. Nielsen, N. C. Friggens, T. Larsen, J. B. Andersen, M. O.
Nielsen, K. L. Ingvartsen
Juan E. Romano, James A. Thompson, Duane C. Kraemer, Mark E.
Westhusin, David W. Forrest, Michael A. Tomaszweski
The purpose of this experiment was to investigate
how early lactating cows adjust their metabolism
and production to acute, but moderate changes in
the energy density of the diet. Sixty dairy cows
were randomly assigned to one of four
treatments: two change-over groups (HNH and
NHN) and two control groups (HHH and NNN),
where H and N refer to a high and normal energy
density in the total mixed ration (TMR),
respectively. The experimental period covered the
first 9 weeks post calving, which was split up in
three 3-week periods. Thus, cows assigned to
HNH or NHN shifted TMR in weeks 4 and 7 after
calving while cows assigned to HHH or NNN were
fed the same TMR for all 9 weeks. Results from
cows on treatment HNH were compared with
group HHH while cows on treatment NHN were
compared with group NNN. When the diet
changed from N to H and H to N, cows increased
and decreased their dry-matter intake (DMI),
respectively compared with control groups. Cows
adjusted milk yield accordingly to changes in DMI,
although not always significantly. Energycorrected milk yield was not significantly affected
by any of the changes in the energy density of the
diet but generally showed same tendencies as
milk yield. Non-esterified fatty acids (NEFA), betahydroxybutyrate in blood and milk and
triacylglycerol and glycogen content in the liver
were not significantly affected by changes in the
energy density of the diet, except from NEFA at
one change. Glucose increased more when the
diet changed from N to H and increased less when
the diet changed from H to N, compared with
control groups, although not always significantly.
Collectively, these results suggest that cows
adjust their DMI and partly milk yield according to
the energy density of the diet and therefore only
limited effects were observed in physiological
parameters.
The objective was to estimate the effect of
palpation per rectum (for early pregnancy
diagnosis) on embryo/fetal viability in dairy cattle.
A controlled, randomized block-design experiment
with two blocks, one by category, and the other
by number of embryos, was conducted. Fivehundred-and-twenty pregnant dairy cows and
heifers with a viable embryo detected by
transrectal ultrasonography (TRUS) between days
29 and 32 after AI were included. The pregnant
females were randomly allocated into two nearly
equal groups: palpation per rectum (PAL group; n
= 258) and no palpation per rectum (NPAL group;
n = 262). The PAL group was submitted to
palpation per rectum (PPR) using the fetal
membrane slip (FMS) technique once between
days 34 and 41 of pregnancy. The fetal
membrane slip consisted of compressing the
pregnant uterine horn and allowing the
chorioallantoic membrane to slip between the
fingers. Both groups were submitted to two
additional TRUS at days 45 and 60 of pregnancy,
to monitor the potential immediate and delayed
deleterious effects of PPR on embryo and fetal
viability, respectively. A diagnosis of embryo/fetal
death was made when there was no embryo/fetal
heart beat or the absence of positive signs of
pregnancy in an animal previously diagnosed
pregnant, or the presence of signs of embryo/fetal
degeneration. The overall rate of embryo/fetal
death was 14.0% (73/520). Embryonic death
(10%; 52/520) was higher than fetal death
(4.5%; 21/468; P < 0.001). Embryo/fetal
mortality was higher in cows (16.4%; 59/360)
than in heifers (8.8%; 14/160; P < 0.025) and in
cattle with twin (25.5%; 12/47) versus singleton
pregnancies (12.9%; 61/473; P < 0.025), but was
not different (P > 0.05) between PAL (14.7%;
38/258) and NPAL (13.4%; 35/262). In
conclusion, PPR between days 34 and 41 of
pregnancy using the fetal membrane slip
technique did not affect embryo/fetal viability.
ncn@landscentret.dk
roma0033@umn.edu
Journal of Dairy Science 2007;90:649–658
RELATIONSHIPS AMONG MILK PRODUCTION, ENERGY
BALANCE, PLASMA ANALYTES, AND REPRODUCTION IN
HOLSTEIN-FRIESIAN COWS
J. Patton, D. A. Kenny, S. McNamara, J. F. Mee, F. P. O’Mara, M. G.
Diskin, and J. J. Murphy
Associations were examined between components
and indicators of early lactation energy balance
(EB) and measures of fertility in Holstein cows.
Milk production, dry matter intake (DMI), body
condition score (BCS), and endocrine and
metabolite data from 96 cows were analyzed
using multivariate logistic regression and survival
analysis. Fertility variables investigated were
interval to commencement of luteal activity (CLA), calving to conception interval (CCI), and
conception rate to first service (CON1). Mean daily
EB, milk protein content, and DMI during the first
28 d in milk were associated positively with CON1.
Cows having poorer BCS (≤2.25) at first service
had a lower CON1. Positive associations were
identified among EB, milk protein content, DMI,
and the likelihood of a shorter interval to C-LA.
Cows having greater DMI and a more positive EB
had an increased likelihood of a shorter CCI,
whereas a lower nadir BCS was associated with an
increased likelihood of a longer CCI. Milk yield was
not associated with any of the fertility variables
investigated. A greater plasma concentration of
insulin-like growth factor I (IGF-I) during the first
2 wk of lactation was associated with a greater
CON1 and an increased likelihood of a shorter
interval to C-LA. In conclusion, we identified DMI
as the principal component of EB influencing
subsequent fertility. Furthermore, results indicate
that milk protein content and plasma IGF-I
concentration in early lactation may be useful
indicators of reproductive efficiency.
john.murphy@teagasc.ie
Journal of Dairy Science 2007;90:2788–2796
THE EFFECT OF SUBCLINICAL KETOSIS IN EARLY
LACTATION ON REPRODUCTIVE PERFORMANCE OF
POSTPARTUM DAIRY COWS
R. B. Walsh, J. S. Walton, D. F. Kelton, S. J. LeBlanc, K. E. Leslie,
and T. F. Duffield
Data generated from 796 Holstein cows enrolled
in a clinical trial to investigate the health effect of
a monensin controlled release capsule were
analyzed to investigate the association between
circulating serum β-hydroxybutyrate (BHBA)
concentration in the periparturient period and
subsequent reproductive performance. Overall,
accounting for both repeated measures within
cow and clustering at the herd level, nonpregnant cows after first insemination tended to
have increased circulating BHBA concentrations
from 3 wk before calving to 9 wk after calving
relative to pregnant cows. Including the
interaction between the week of sample collection
and pregnancy outcome, non-pregnant cows had
higher circulating BHBA concentrations in the
second week after calving than cows diagnosed
pregnant after first artificial insemination. Within
individual weeks, cows with circulating BHBA
concentrations ≥1,000 _mol/L in the first week
postpartum were less likely to be diagnosed
pregnant after first insemination. In the second
week postpartum, the cows with circulating BHBA
concentrations ≥1,400 _mol/L were significantly
less likely to be pregnant after first artificial
insemination. A dose response relationship was
found when a comparison of the probability of
pregnancy after first insemination and duration of
elevated
circulating
ketone
bodies
was
investigated. The probability of pregnancy was
reduced by 20% in cows diagnosed subclinically
ketotic in either the first or second week
postpartum. Nevertheless, cows above the
subclinical ketosis threshold in both the first and
second week postpartum were 50% less likely to
be pregnant after first insemination. Similarly, the
median time to pregnancy increased in cows
experiencing elevated BHBA concentrations in
either (124 d) or both (130 d) the first and second
week postpartum relative to cows never
experiencing elevated BHBA concentrations
(108d). To further investigate this, the effect of
elevated circulating BHBA was permitted to vary
with time. The effect decreased with time, such
that the daily probability of pregnancy increased
similar to nonsubclinically ketotic cows by
approximately 160 d in milk. From this analysis,
both the relative circulating concentration of BHBA
and the duration of elevated circulating BHBA
were negatively associated with the probability of
pregnancy at first service.
rwalsh@uoguelph.ca
Theriogenology 2007;67:346–352
ARTIFICIAL INSEMINATION INCREASES THE PROBABILITY
OFA MALE CALF IN DAIRY AND BEEF CATTLE
D.P. Berry, A.R. Cromie
The objective of this study was to determine if
natural mating affected secondary sex ratio. Data
consisting of 642,401 calving records from the
Irish national database, during the years 2002–
2005, were used in the analysis. Factors affecting
the logit of the probability of a male calf being
born were determined using multiple regression
generalised estimating equations with sire of the
calf included as a repeated effect. Month of the
year at calving, sex of the previous calf born
within dam, breed of service sire, parity of dam
and type of mating (i.e., natural or artificial
insemination) significantly (P < 0.05) affected the
likelihood of a male calf being born. Male calves
were more likely to be born in the warmer months
of the year, when the sex of the previous calf
born to the same dam was male, in older cows
and when the service sire was a beef breed. No
significant interaction between the main effects
existed. The odds of a male calf being born,
following adjustment for confounding effects,
varied from 1.04 to 1.08 (P < 0.01) across the
years of analysis when artificial insemination was
used compared to natural mating. This equates to
a 1% unit increase in the probability of a male calf
being born following artificial insemination.
donagh.berry@teagasc.ie
Biology of Reproduction 2007;77:9–17
IMPACT OF DIETARY FATTY ACIDS ON OOCYTE QUALITY
AND DEVELOPMENT IN LACTATING DAIRY COWS
Ali A. Fouladi-Nashta, Carlos G. Gutierrez, Jin G. Gong, Philip
C. Garnsworthy, and Robert Webb
The purpose of this study was to examine the
effects of level of rumen inert fatty acids on
developmental competence of oocytes in lactating
dairy cows. Estrous cycles were synchronized in
22 cows on a silage-based diet supplemented with
either low (200 g/day) or high (800 g/day) fat. A
total of 1051 oocytes were collected by
ultrasound-guided ovum pickup (OPU) in seven
sessions/cow at 3–4 day intervals. Oocytes were
matured, fertilized, and cultured to the blastocyst
stage in vitro. Embryo quality was assessed by
differential staining of Day 8 blastocysts. The
high-fat diet reduced numbers of small and
medium follicles. There was no effect on the
quality of oocytes (grades 1–4) or cleavage rate.
However, high fat significantly improved
blastocyst production from matured (P, 0.005)
and cleaved (P, 0.05) oocytes. Blastocysts from
the high-fat group had significantly more total,
inner cell mass and trophectoderm cells than the
low-fat group (P, 0.05). Regression analysis
showed negative effects of milk yield (P, 0.001),
dry matter intake (P, 0.001), metabolizable
energy intake (P, 0.005), and starch intake (P,
0.001) on blastocyst production in the low-fat
group but not in the high-fat group. Within the
low-fat group, blastocyst production was
negatively related to growth hormone (P, 0.05)
and positively related to leptin (P, 0.05). The
lowfat group had higher nonesterified fatty acids
than the high-fat group (P, 0.05). In conclusion,
higher milk yields were associated with reduced
developmental potential of oocytes in cows given
a low-fat diet. Provision of a high-fat diet buffered
oocytes against these effects, resulting in
significantly improved developmental potential.
bob.webb@nottingham.ac.uk
Reproduction 2007;133:155–163
RELATIONSHIP BETWEEN METABOLIC HORMONES AND
OVULATION OF DOMINANT FOLLICLE DURING THE FIRST
FOLLICULAR WAVE POST-PARTUM IN HIGH-PRODUCING
DAIRY COWS
Chiho Kawashima, Saori Fukihara, Mayumi Maeda, Etsushi Kaneko,
Carlos Amaya Montoya, Motozumi Matsui, Takashi Shimizu,
Nobuyoshi Matsunaga, Katsuya Kida, Yoh-Ichi Miyake, Dieter Schams
and Akio Miyamoto
Recent studies suggest that IGF-I is a crucial
regulatory factor in follicular growth during early
post-partum period. The aim of the present study
was to determine in detail the changing profiles of
metabolic and reproductive hormones in relation
to ovulation of the dominant follicle (DF) of the
first follicular wave post-partum in high-producing
dairy cows. Plasma concentrations of related
hormones in 22 multiparous Holstein cows were
measured from 4 weeks pre-partum to 3 weeks
post-partum, and the development of DF was
observed with colour Doppler ultrasound. Thirteen
cows showed ovulation by 15.2 days post-partum.
Anovulatory cows showed higher GH and lower
IGF-I levels than those in ovulatory cows during
the peri-partum period. Each DF developed
similarly, and a clear blood flow in the follicle wall
was observed despite ovulation or anovulation. In
addition, detailed endocrine profiles were
analyzed in 9 out of the 22 cows. Five cows
showed an increase in plasma oestradiol-17b (E2)
with follicular growth followed by E2 peak, LH
surge and ovulation. In these cows, plasma IGF-I
concentrations remained high until 10 days postpartum followed by a gradual decrease.
Subsequently, the insulin level increased together
with the E2 peak towards ovulation. These
profiles were not observed in anovulatory cows.
In conclusion, our data strongly support the
concept that IGF-I and insulin represent
‘metabolic signals’ of the resumption of ovarian
function post-partum in high-producing dairy
cows. Moreover, we provide the first visual
evidence that both ovulatory and anovulatory DFs
of the first follicular wave post-partum are
similarly supplied with active blood flow.
akiomiya@obihiro.ac.jp
Theriogenology 2007;67:824–834
REPRODUCTIVE PERFORMANCE OF LACTATING DAIRY
COWS AND HEIFERS RESYNCHRONIZED FOR A SECOND
INSEMINATION WITH AN INTRAVAGINAL
PROGESTERONE-RELEASING DEVICE FOR 7 OR 8 D WITH
ESTRADIOL BENZOATE INJECTED AT THE TIME OF DEVICE
INSERTION AND 24 H AFTER REMOVAL
J. Cavalieri, G. Hepworth, V.M. Smart, M. Ryan, K.L. Macmillan
One aim of this study was to compare the
reproductive performance of cows and heifers
when resynchronizing returns to estrus for a
second insemination by treating with an
intravaginal progesterone-releasing device (IVD)
for 7 or 8 d when estradiol benzoate (EB) was
administered at the start of treatment and again
24 h after device removal. An additional aim was
to document the pattern of onset and
characteristics of estrus with each resynchrony
treatment. Lactating cows in three herds were
synchronized for a first estrus and AI by treatment
with an IVD for 8 d, starting on Day 0,
cloprostenol (0.5 mg im) at device removal and
EB at device insertion (2.0 mg im) and 24 h after
removal (1.0 mg im). Cows were resynchronized
for a second estrus starting on Day 23 by
reinsertion of IVDs for 7 (IVD-7-EB; n = 449) or 8
d (IVD-8-EB; n = 445) with EB (1.0 mg im)
administered at device insertion and 24 h after
removal. Cows were resynchronized for a third
estrus by administration of EB (1.0 mg im) on Day
46, but subsequent treatments (no further
treatment, reinsertion of CIDR or administration
of EB on Day 55) varied among herds as part of
separate studies. Maiden heifers (7-Day, n = 68;
8-Day, n = 69) were similarly treated as cows in a
separate herd, but doses of EB were always 1.0
mg im at device insertion and 0.75 mg im 24 h
after removal. Heifers were not resynchronized for
a third estrus. Cattle were inseminated on
detection of estrus at each synchronized estrus.
Cumulative pregnancy rates 4 week (66.0%,
276/418 versus 59.1%, 247/418) and 7 week
(72.7%, 304/418 versus 67.7%, 283/418) after
the start of AI were greater (P < 0.05) in the IVD7-EB cows compared to the IVD-8-EB cows,
respectively; this was associated with a 9%
increase in conception rates at the second estrus
(P = 0.051) in the IVD-7-EB cows. Treatment did
not significantly affect reproductive performance
in heifers. Characteristics of estrus measured with
radiotelemetry did not differ significantly between
the two treatment groups, but more cows were
detected in estrus 36 h after removal of IVDs in
the IVD-8-EB cows compared to the IVD-7-EB
cows (P < 0.05). We concluded that reproductive
performance in resynchronized dairy cows but not
heifers was greater following resynchronization of
estrous cycles after AI with an IVD for 7
compared to 8 d when EB was injected at the
start of treatment and 24 h after device removal.
john.cavalieri@jcu.edu.au
Theriogenology 2007;67:1386–1392
PREGNANCY DIAGNOSIS IN DAIRY COWS BY WHEY
PROGESTERONE ANALYSIS: AN ROC APPROACH
M. Faustini, M. Battocchio D. Vigo A. Prandi M.C. Veronesi A. Comin
F. Cairoli b
Concentration of progesterone in milk may be
used to predict pregnancy status of dairy cattle by
the 21st day after insemination. However, the
accuracy of this method may be affected by fatsolubility of progesterone and sample storage
conditions. After coagulation of a milk sample with
rennet, an alternative method is to quantify
progesterone concentration in whey with a novel,
validated EIA. In this experiment, a receiver
operating characteristic (ROC) analysis was
performed to estimate the optimal discrimination
point for whey progesterone concentration, using
a sample of 991 Friesian cows evaluated between
the 42nd and 44th day after insemination. Cows
also were diagnosed for pregnancy by rectal
palpation at this time. The overall conception rate
at palpation was 57%. ROC analysis indicated that
259 pg/mL progesterone in whey was the most
effective cutoff to discriminate correctly between
pregnant and non-pregnant cows. Using this point
for prediction, sensitivity was 98.2%, specificity
was 70.9% and the area under ROC curve was
0.859, levels generally considered to denote
moderate accuracy. The negative likelihood ratio
at the cutoff of 259 pg/mL was 0.02, indicating
satisfactory performance in detecting negative
subjects, while the positive likelihood ratio (+LR =
3.37) suggested average performance. In
conclusion, EIA of progesterone concentration in
whey is a viable method for predicting pregnancy
status in cows. However, operators should take
management objectives for the herd into account
in determining the cutoff point and also
considering important influencing variables such
as conception rate in the herd. This method can
provide diagnostic support for efforts to improve
reproductive success, especially in low-fertility
herds.
massimo.faustini@unimi.it
Journal of Dairy Science 2007;90:2804–2814
RECTAL TEMPERATURE, CALVING-RELATED FACTORS,
AND THE INCIDENCE OF PUERPERAL METRITIS IN
POSTPARTUM DAIRY COWS
M. E. Benzaquen, C. A. Risco, L. F. Archbald, P. Melendez, M. J.
Thatcher, and W. W. Thatcher
The objectives of this study were as follows: 1) to
evaluate the association among abnormal calving,
parity, and season on the incidence of puerperal
metritis (PM) and clinical endometritis (CE) during
d 3 to 13 and 20 to 30 postpartum, respectively;
2) to describe the rectal temperature (RT) of cows
with PM before diagnosis; and 3) to document
associations among PM, CE, and reproductive
performance in lactating dairy cows. This study
followed a prospective observational study design.
Cows were classified as having an abnormal
calving status (AC), i.e., cows calving with
dystocia, twins, retained fetal membranes, or
some combination of these conditions, and having
a normal calving status (NC). Daily RT was
recorded from d 3 to 13 postpartum for all cows,
and health examinations were performed on cows
that appeared not well. A total of 450 calvings
were evaluated. Cows with an AC had greater
odds of PM than cows with NC [adjusted odds
ratio (AOR) = 4.8; 95% confidence interval (CI) =
2.9 to 8.0). A season by parity interaction showed
that primiparous cows that calved during the
warm season had lower AOR of PM than during
the cool season (0.24; 95% CI = 0.09 to 0.62),
whereas multiparous cows did not have seasonal
effects on PM (1.43; 95% CI = 0.65 to 3.18).
Cows with AC have greater AOR for CE than cows
with NC (2.8; 95% CI = 1.7 to 4.9), and greater
AOR of CE were detected in cows diagnosed with
PM than in cows without PM (2.2; 95% CI = 1.1
to 3.9). Rectal temperature in cows with PM
increased significantly 24 h before diagnosis of
PM, reaching 39.2 ± 0.05°C on the day of
diagnosis. In cows with PM and fever at diagnosis,
the RT began to increase from 72 to 48 h before
the diagnosis of PM and continued to increase to
39.7 ± 0.09°C on d 0 (day of diagnosis).
Nonetheless, cows with PM without fever at
diagnosis had no daily increases in RT before
diagnosis of PM. Still, the RT on d 0 was different
from cows without PM. Cows without PM had a
stable RT (38.6 ± 0.01°C). There were no
detected differences in first-service conception
risk or cumulative pregnancy risk by 150 d
postpartum between cows with or without PM.
Still, a season effect on first-service conception
AOR (warm vs. cool = 0.98; 95% CI = 0.18 to
0.72) and accumulated pregnancy AOR by 150 d
postpartum was detected (warm vs. cool = 0.18;
95% CI = 0.10 to 0.33).
riscoc@mail.vetmed.ufl.edu
Theriogenology 2007;67:590–597
EFFICACY OF AN INJECTION OF DINOPROST
TROMETHAMINE WHEN GIVEN SUBCUTANEOUSLY ON
LUTEAL REGRESSION IN LACTATING HOLSTEIN COWS
Ricardo C. Chebel , Jose E.P. Santos b, Heloísa M. Rutigliano b,
Ronaldo L.A. Cerri b
The objectives of these studies were to evaluate
the efficacy of a PGF2a (PGF) analog given
through different routes on causing luteal
regression in lactating dairy cows. In Experiment
1, lactating Holstein cows (n = 118) at random
stages of lactation were blocked by parity and
days in milk (DIM) and, within each block,
randomly assigned to receive PGF as an intramuscular
(IM)
injection
in
the
semimembranous/semitendinous muscle (CON),
subcutaneous (SC) injection in the cervical area
(SCN), or SC injection in the ischio-rectal fossa
(IRF). Blood was sampled at 0, 12, 24, 36, and 48
h after treatment for assessment of progesterone
concentration. In Experiment 2, a total of 379
lactating Holstein cows, 46 ± 7 DIM, were blocked
by DIM and, within each block, randomly assigned
to receive treatment similar to CON or IRF groups
from Experiment 1. Blood was sampled 0 and 48
h after treatment for assessment of progesterone
concentration.
Cows
were
classified
as
experiencing luteal regression when progesterone
concentration was <1.0 ng/mL or <40% of initial
concentration (0 h = 100%). In Experiment 1,
there was no effect of route of PGF treatment on
decline in progesterone concentration and on the
proportion of cows experiencing luteal regression
by 12, 24, 36, and 48 h after treatment. Similarly,
in Experiment 2, route of treatment did not affect
either the decline in progesterone concentration
or the proportion of cows that had luteal
regression by 48 h after treatment. Treatment of
lactating dairy cows with 25 mg of PGF given SC
in the ischio-rectal fossa did not affect either the
decline in progesterone concentration or the
proportion of cows that experienced luteal
regression by 12, 24, 36, and 48 h after PGF
treatment.
rchebel@uidaho.edu
Animal 2007;1:29–43
intended for rebreeding that were back in-calf
again within 100 days of calving (ICR-100) and
the proportion of cows that reappeared again with
365 (RR-365) and 400 days (RR-400) of a
previous calving were considered in addition to
the traditional measures of reproductive
performance. Each 100-kg increase in genetic
merit for milk yield was associated with an
increased interval to first service (IFS) and calving
index (CI) of 1.4 (P, 0.001) and 1.8 days (P,
0.001), respectively, a 0.5% increase (P , 0.05) in
calving rate to first insemination (CR-1) and 0.8%
increase in RR-400. Each £10 increase in £PIN
(the economically weighted yield selection index
used in the UK that takes account of butterfat and
protein yields) was associated with an increased
IFS and CI of 1.5 (P, 0.001) and 3.0 days (P,
0.001), respectively. Cows with increased genetic
merit for milk yield and £PIN were more likely to
re-calve (RR-overall; P, 0.001). Each 1000-kg
increase in 305-day milk yield was associated with
an increased IFS and CI of 3.2 (P, 0.001) and 7.8
days (P, 0.001), respectively, and a 13.6 (P,
0.001), 22.4 (P, 0.001), 19.9 (P, 0.001) and
19.0% (P, 0.001) decrease in CR-1, ICR-100, RR365 and RR-400, respectively. A 10-kg increase in
maximum yield was associated with a 6.6-day
increase in CI (P, 0.001) and a 14.9 (P, 0.001),
18.3 (P, 0.001), 9.6 (P, 0.05) and 14.2% (P,
0.001) decrease in CR-1, ICR-100, RR-365 and
RR-400, respectively. Fertility performance was
also associated with season of calving, lactation
number and dystocia score. Level of production
had a larger effect on fertility performance than
genetic merit for milk production suggesting that
infertility at an individual cow level is more likely
to be associated with increased production and an
inability to meet the nutritional requirements of
the cow.
david.mackey@dardni.gov.uk
ASSOCIATIONS BETWEEN GENETIC MERIT FOR MILK
PRODUCTION AND ANIMAL PARAMETERS AND THE
FERTILITY PERFORMANCE OF DAIRY COWS
D. R. Mackey, A. W. Gordon, M. A. McCoy, M. Verner, C. S. Mayne
Relationships between genetic merit for milk
production and animal parameters and various
parameters of reproductive performance were
examined using multilevel binary response
analysis in a study of 19 dairy herds for three
successive years, representing approximately
2500 cows per year. The proportion of cows
Theriogenology 67 (2007) 494–501
A META-ANALYSIS OF THE EFFECTS OF VITAMIN E
SUPPLEMENTATION ON THE INCIDENCE OF RETAINED
FOETAL MEMBRANES IN DAIRY COWS
N. Bourne, R. Laven, D.C. Wathes, T. Martinez, M. McGowan
A meta-analysis was performed to consolidate the
results of studies which have evaluated the effects
of Vitamin E supplementation during the dry
period on the risk of retained foetal membranes
(RFM) in the dairy cow. Twenty studies
demonstrated a beneficial response to Vitamin E
whilst 21 found no benefit and 3 reported an
increase in the incidence of RFM in treated cows.
The odds ratios (OR) of the available studies
exhibited
significant
heterogeneity,
so
multivariable logistic regression analysis was
performed to enable the identification of factors
associated with the response to Vitamin E
supplementation. Our multivariable analysis
included parity and Vitamin E supplementation
(control/treated) in the model, because all other
factors were co-linear. Results indicated that
Vitamin E supplementation led to a reduction in
the incidence of RFM. A second multivariable
analysis was undertaken on a subset of the data
including only supplemented cows to determine
the influence of supplementation factors on the
risk of RFM. All factors were co-linear with each
other, therefore, only type of Vitamin E
supplementation was included in this analysis.
The regression model demonstrated that
administration of the synthetic Vitamin E atocopheryl acetate was associated with a lower
risk of RFM than treatment with natural Vitamin E
(a-tocopherol) (P = 0.047, OR = 0.49), whereas
the difference between the synthetic Vitamin E atocopherol acetate and natural Vitamin E just
failed to attain statistical significance (P = 0.059,
OR = 0.53). Overall the analyses indicate that
Vitamin E supplementation during the dry period
is associated with a reduced risk of RFM, and that
the synthetic forms of Vitamin E are more
effective than the natural compound.
that act via intracellular signaling pathways. Here,
we show the differences in Akt, Erk, c-Jun Nterminal protein kinase, and p-38 signaling
pathways between dominant and subordinate
follicles at the dominance stage of the follicle
wave. However, earlier in the follicle wave
(dominant follicle selection), there were only
differences in the levels of Akt and Erk signal
transduction proteins among dominant and
subordinate follicles. Using this profile of Akt and
Erk protein expression in granulosa and theca
cells of selected dominant follicles compared with
subordinate follicles, we suggest a predictive
model to identify future dominant and subordinate
follicles from the pool of otherwise similar cohort
follicles at the time of follicle wave emergence.
We conclude that the Erk and Akt signal
transduction pathways are important for dominant
follicle
selection
and
development
and,
furthermore, that the observed differences in
these pathways mark the future dominant follicle
from subordinate follicles before differences in
follicular diameter, follicular fluid estradiol, and
IGFBP-4 concentrations are apparent.
nbourne@rvc.ac.uk
Our objective was to assess the effect on heifer
pregnancy rate of deposition at three sites within
the uterus of frozen-thawed sex-sorted sperm at a
fixed time after estrus synchronization. Estrus was
synchronized in 209 heifers by administration of
PGF2a 14 days apart. At 80–82 h after the second
PGF2a injection, X-chromosomes bearing fractions
of semen with 2.2 _ 106 sperm in insemination
dose were used for single insemination into the
uterine body (UB-AI, n = 91) or for intracornual
deposition in the middle of the uterine horn (MHAI, n = 57) or close to the utero-tubal junction
(UTJ-AI, n = 61). The overall pregnancy rate was
43.1%. Pregnancy rates did not differ (P > 0.05)
among sites of sperm sperm deposition, between
the two farms at which the heifers were kept or
between the two bulls producing the semen.
Within UB-AI, MH-AI and UTJ-AI treatments,
Reproduction 2007;133:617–626
AKT AND ERK SIGNAL TRANSDUCTION PATHWAYS ARE
EARLY MARKERS OF DIFFERENTIATION IN DOMINANT
AND SUBORDINATE OVARIAN FOLLICLES IN CATTLE
K E Ryan, S M Casey, M J Canty, M A Crowe, F Martin and A C O
Evans
Dominant follicles are those that continue to
develop and have the potential to ovulate while
subordinate follicles regress. Characteristics of
dominant follicles include a larger diameter,
higher intrafollicular estradiol, and lower IGFbinding
protein
(IGFBP)-4
concentrations
compared with other cohort follicles. Follicle
development is regulated by endocrine hormones
alex.evans@ucd.ie
Theriogenology 2007;67:754–759
PREGNANCY PERCENTAGE FOLLOWING DEPOSITION OF
SEX-SORTED SPERM AT DIFFERENT SITES WITHIN THE
UTERUS IN ESTRUS-SYNCHRONIZED HEIFERS
J. Kurykin, U. Jaakma, M. Jalakas, M. Aidnik, A. Waldmann, L. Majas
pregnancy rates were 41.8%, 49.1% and 39.3%,
respectively (P > 0.05). Pooled across classes for
deposition site, pregnancy rate was 25.1% higher
(P < 0.01) for heifers showing strong signs of
estrus than for heifers showing weak signs of
estrus (45.9 versus 20.8%, respectively).
Embryonic and fetal loss from diagnosis of
pregnancy to term and at calving equalled 5.6%.
Of 88 calves of identified sex, 93.2% were female.
In conclusion, pregnancy rates of heifers did not
differ significantly following deposition of 2.2 x 106
sex-sorted sperm 80–82 h after the second PGF2a
injection near the utero-tubal junction, in the
middle of the horn or into the uterine body.
Jevgeni.Kurykin@emu.ee
Animal Reproduction Science 2007;100:257–263
CONCENTRATIONS OF FREE RADICALS AND BETAENDORPHINS IN REPEAT BREEDER COWS
A. Rizzo, G. Minoia, C. Trisolini, R. Manca, R.L. Sciorsci
Repeat breeding (RB) is one of the major
problems that affect the reproductive efficiency
and economy of milk production in dairy animals.
So far, the etiopathogenesis of this pathology has
not been defined completely. Stress has been
hypothesized to be a cause of impaired
reproductive efficiency. Stress may cause an
overproduction of beta-endorphins and free
radicals; in particular, reactive oxygen species
(ROS). The aim of this work is to determine the
concentrations of these substances in RB cows
and to evaluate the correlation with the serum
level of progesterone. The study was performed
on 60 dairy cows: 26 RB and 34 control cows.
Blood samples were collected on day 12 and day
16, after artificial insemination (AI) in all subjects,
in order to assess the concentrations of
progesterone, free radicals and beta-endorphins.
The stressors, free radicals and beta-endorphins,
that we considered, were higher in repeat
breeders (day 12, 93.32(±1.91) UCarr and
0.50(±0.03) ng/ml; day 16, 94.42(±1.91) UCarr
and 0.61(±0.03) ng/ml), with a lower level of
progesterone, which probably is responsible for
failure to conceive. The stress factors (free
radicals and beta-endorphins) may actually
enhance each other and induce an inhibition of
progesterone synthesis in repeat breeders.
r.sciorsci@veterinaria.uniba.it
Theriogenology 2007;67:632–638
FACTORS AFFECTING THE FERTILITY OF HIGH
PRODUCING DAIRY HERDS IN NORTHEASTERN SPAIN
I. García-Ispierto, F. López-Gatius, P. Santolaria, J.L. Yániz, C.
Nogareda, M. López-Béjar
Infertility has been often correlated to a rising
milk yield in high producing dairy cattle. The aim
of the present study was to evaluate, using
logistic regression procedures, the effects of
several management indicators on the fertility of
four dairy herds in northeastern Spain. Data
derived from 10,965 artificial insemination (AI).
The factors examined were: herd, milking
frequency (three versus two milkings per day),
lactation number, previous twinning and disorders
such as placenta retention and pyometra, milk
production at AI, the inseminating bull, season
(warm versus cool period) and year effects, AI
technician and repeat breeding syndrome (cows
undergoing four or more AI). Our findings
indicated no effects on fertility of the herd, year of
AI, previous twining, placenta retention and
pyometra and milk production at AI. Based on the
odds ratios, the likelihood of pregnancy
decreased: in cows milked three times per day (by
a factor of 0.62); for each one unit increase in
lactation number (by a factor of 0.92); for
inseminations performed during the warm period
(by a factor of 0.67); in repeat breeder cows (by a
factor of 0.73); and when 3 of the 45
inseminating bulls included in the study were used
(by factors of 0.35, 0.43 and 0.44, respectively).
Of the 13 AI technicians participating in the study,
3 were related to a fertility rate improved by odds
ratios of 1.86, 1.84 and 1.30, respectively,
whereas 2 technicians gave rise to fertility rates
reduced by odds ratios of 0.64 and 0.49,
respectively. Under our study conditions,
management practices were able to compensate
for the effects of previous twining and
reproductive disorders such as placenta retention
and pyometra. However, fertility was significantly
affected by the factors milking frequency, AI
technician, inseminating bull, repeat breeding
syndrome, lactation number and AI season.
flopez@prodan.udl.es
Federación de Colegios y Asociaciones de Médicos
Veterinarios Zootecnistas de México, A.C.
www.fedmvz.com
Organización Mundial de Sanidad Animal.
Foro: Complejo Abortivo en Bovinos
Universidad Autónoma de Puebla
Centro de Convenciones, Puebla, Pue.
19 y 20 de octubre de 2007
Informes: direccion@comitepecuario
conevet@yahoo.com
Ganadería de Doble Propósito en el Trópico
Universidad Nacional Autónoma de México
Facultad de Medicina Veterinaria y Zootecnia
Unión Ganadera Regional del Norte de Veracruz.
Auditorio de la Unión Ganadera Regional del Norte
de Veracruz. Tuxpan, Ver.
25 y 26 de octubre de 2007
Informes: (236) 32 43941
(783) 83 40164
www.oie.int
Organización de las Naciones Unidas para la
Agricultura y la Alimentación.
www.fao.org
Organización Panamericana de la Salud.
www.cinu.org.mx/onu/estructura/mexico
/org/ops.htm
Organismo Internacional Regional de Sanidad
Agropecuaria.
www.oirsa.org
Productora Nacional de Biológicos Veterinarios.
www.pronabive.gob.mx
Bovinotecnia Boletín técnico virtual. Departamento
de Producción Animal: Rumiantes. FMVZUNAM
www.fmvz.unam.mx/bovinotecnia/
Revista Veterinaria México
http://www.fmvz.unam.mx/fmvz/revvetm
ex/revvetmex.htm
Dirección General de Salud Animal
http://senasicaw.senasica.sagarpa.gob.mx
/portal/html/salud_animal/introduccion/i
ntroduccion.html
Secretaría de Agricultura, Ganadería, Desarrollo
Rural, Pesca y Alimentación.
http://www.sagarpa.gob.mx
Confederación
Ganaderas
Nacional
de
Servicio Nacional de Sanidad, Inocuidad y Calidad
Agroalimentaria
http://www.senasica.sagarpa.gob.mx/
Organizaciones
http://www.cnog.com.mx
Instituto Nacional de Investigaciones Forestales,
Agrícolas y Pecuarias.
http://www.inifap.gob.mx
Facultad de Medicina Veterinaria y Zootecnia,
UNAM.
http://www.fmvz.unam.mx
Academia Veterinaria Mexicana, A.C.
http://www.academiaveterinaria.org
Asociación Mexicana de Médicos Veterinarios
Especialistas en Bovinos, A.C.
http://www.AMMVEB.net
NRB 1 ,2007