Oral and Poster Abstracts

simultaneously, and these delay the first ovulation after calving. In
conclusion, to ovulate early after calving, cows should be given
better management in dry period, such as to avoid low DMI. For
monitoring nutritional and health status, b-carotene is a good
indicator.
112 ß-Carotene Deficiency in Dairy Cattle: Reasons and
Prevention
W. Schliffka
Dairy Production Research Centre, Germany
An adequate supply of ß-Carotene is of prime importance for dairy
cows. ß-Carotene is not only the natural precursor of vitamin A for
ruminant animals; it has also a very important function as a fertility
vitamin in these species. Access to pasture or good quality grass
silage should guarantee an adequate supply of ß-Carotene to dairy
cows. However, modern rations for high yielding dairy cows are
often based on total mixed rations (TMR). TMRs in early lactation
frequently contain more than 50% maize silage and cows usually
have little or no access to pasture. Maize silage has a negligible ß-
Carotene concentration. The capacity of grass products to
compensate for the low ß-Carotene content in maize based rations is
often overestimated. DSM survey results from 1999-2007 show that
the ß-Carotene content of grass silage is highly variable and
unpredictable. This is very much related to the crop and conservation
technique. Moreover, the oxidative losses of ß-Carotene during
harvest, wilting and ensiling can be considerable. Compared to the
pre-ensiled fresh grass, ß-Carotene losses can easily exceed 50%
during storage and decreases further once the silo is opened. The
correlation between the ß-Carotene concentration of the diet and the
ß-Carotene concentration in plasma of dairy cows is very strong. The
optimum level of ß-Carotene in the blood should exceed 3.5 µg/ml.
Recent surveys of blood plasma samples in intensive dairy herds in
selected countries worldwide showed that the majority of the cows
do not exceed ß-Carotene levels of 2.5 µg/ml plasma. These findings
confirm that the ß-Carotene concentration in dairy cow rations is
often insufficient to fulfill the requirements in early lactation. An
inadequate supply of ß-Carotene leads to a dramatic decline in
reproductive performance. The following are typical symptoms,
weak or silent heat, delayed ovulation, low fertility rate, increased
occurrence of cystic ovaries, early embryonic losses and retained
placenta. Reproductive disorders result in losses of up to 150 _ per
cow per year. They play a key role for early culling in dairy herds.
Inadequate dietary ß-Carotene can be easily rectified with
supplementary ß-Carotene added to minerals or compound feed. If
blood levels are < 1.5 µg/ml the cow is deficient and
supplementation of 500 mg ß-Carotene/cow/day is recommended.
Levels between 1.5 – 3.5 µg/ml are classified marginal and require at
least the supplementation of 300 mg ß-Carotene/cow/day. The
supplementation should start at the beginning of the dry period to
support ovum development and heat intensity but also for optimum
fortification of the colostrum. Supplementation should be continued
until the next pregnancy is confirmed.
113 Factors Related to the Reproductive Performance of Dairy
Herds in Chile
L. Poo
Private, Clínica de Rumiantes, Osorno, Chile
Chile is a very long country and the climate is very different between
north and south. The main milk production areas are in the south with a
production of more than 70% of the total country milk production.
Basically there are two models of milk production. One is based on the
use of cows with high volume of individual productions which are
frequently fed with high amount of concentrated feed. In Chile several
aspects including management, nutrition and genetics are responsible
for the reproductive level in cows and this topic is discussed.
Reproductive parameters more frequently used in Chile are discussed
and the conclusion is that the reproductive performance of dairy herds
in the southern Chile is not affected by serious problems but it must be
improved in factors such as heat detection, age at first calving,
nutrition, artificial insemination use, as well as record keeping and use
of ultrasonographic techniques.
Key words: Pregnancy rate, conception rate, heat detection, open days,
voluntary waiting period
114 Factors Responsible for Increased Calving Intervals in Crossbred
Cows in India
A. Nanda, J. Singh
Guru Angad Dev Veterinary & Animal Sciences, Animal
Reproduction, Gynaecology & Obstetrics, Ludhiana, India
India made tremendous progress in dairy production through
crossbreeding of indigenous low yielding cows with high yielder
exotic breeds, especially HF, over the last two decades. Compared to
indigenous cows, the crossbreds mature early and calve first at the
age of 31.1 vs 44±2.41 months, and have shorter Inter Calving
Intervals (ICI; 437±28.9 vs 517±53.8 days). However, the crossbred
generations from F2 and beyond have increased reproductive
problems and their ICI increased to 451±34.3 days or even longer.
Conditions like repeat breeding syndrome (RBS; 20-39%), anestrus
(14-48%) and cystic ovaries (30%) have been increasing. Cows with
>75% exotic blood have lower uterine immunity than natives and
hence higher incidence of endometritis. Insufficient pre- and
postpartum nutrition and unhygienic, unscientific conventional
animal husbandry practices also favored uterine infections. Stress of
high milk production, seasonal extremes, and lameness, add to
hormonal abrasions and infertility. Modulation of uterine immunity
in crossbred cows with microbial endometritis has been proposed as
an alternate to conventional treatment with antibiotics / antiseptics
etc. Single intrauterine infusion of 100 g E. coli lipopolysaccharide
(LPS) in 30 ml normal saline or of 500 mg Oyster Glycogen in 50 ml
normal saline induced an influx of neutrophils into the uterine lumen
within 6h. These cleared uterine infections in more than 75% repeat
breeding endometritic cows through enhanced phagocytosis and
substantially improved their fertility (CR 45 - 66.6% vs 12.6% in
untreated controls). General immunomodulation of such cows
through parenteral administration of 10 ml Inmodulen once or twice
(25 mg inactivated cells of Propionibacterium granulosum and 2.0
mg E. coli LPS per 100 ml) also been proposed. Management of
fertility in repeat breeding cows with prolonged estrus, estrus with
suprabasal circulatory P4 and luteal insufficiency could be better
made through either (i) stimulating LH release with exogenous
GnRH or (ii) by early termination of luteal phase using
PGF2·. Although good quality fodder/balanced feeding is
indispensable, supplementation with urea molasses multinutrient
blocks feeding or parenteral soybean oil emulsions proved beneficial
in improving fertility and attaining normal ICI. A comprehensive
approach, however, would need to be involved to deal with infertility
in a holistic way in crossbred cows in India.
Key words: Reproduction, Crossbred Dairy Cow, India
115 Prevalence, Causes, Treatment and Prophylaxis of Cow
Infertility in Poland
E. Malinowski
National Veterinary Research Institute, Department of
Pathophysiology of Reproduction and Mammary Gland, Pulawy,
Poland
The efficiency of reproduction is the best indicator of the adequate
management, feeding, housing, welfare and good health status of
dairy cows. Diseases of the genital tract, metabolic disorders,
mastitis, and lameness are the main causes of subfertility or
infertility in cows. Incidences of the genital tract diseases
significantly ranged among different herds. Embryo mortality and
abortions were noted from 0 to 11.4%, dystocia from 1.2 to 19.4%,
retained fetal membranes from 3.4 to 31.2%, puerperal metritis from
0 to 40.6%, clinical endometritis from 2.8 to 34.7%, ovarian cysts
from 0 to 50%, ovarian afunction from 1.4 to 50% and silent heat
from 1.6 to 49% of cows. Other diseases such as clinical mastitis
ranged from 13 to 72%, clinical ketosis (0-14.5%), lameness (0-
45.3%) and displaced abomasum from 0 to 4% of cows in particular
herds. Fertility indicators: conception rate (26-63%), artificial
insemination index (1.6-3.5), calving-pregnancy period (88-178
days), and culling rate (2.1-12.5%) also differed among the
examined herds. A deficiency or excess of energy and protein, and
deficiency of antioxidants were the main feeding factors that
negatively affected the fertility. Reproductive disorders were also
connected with BVD-MD and IBR-IPV. Infections of the uterus
were caused by Arc. pyogenes, E. coli and other coliforms,
Streptococcus spp. Staphylococcus spp., Bacterioides spp. and other
Reprodiction Workshop 317