<p>Fat supplementation has
potential to improve reproductive performance and increase pregnancy rates in
cattle by increasing the energy density of the diet. However, some of the
positive effects of fat seem to be influenced by the type of fatty acid fed.
Supplementation of omega-3 (n-3) fatty acids increase uptake of n-3 fatty acids
into tissue phospholipids and can mitigate immune and inflammatory responses in
favor of pregnancy maintenance in cattle. However, n-3 fatty acid
supplementation in ruminants has been associated with a decrease in circulating
PGF<sub>2α</sub>, which may delay CL regression, extend an animal’s time in
diestrus, and prevent ovulation. Prostaglandin F<sub>2α</sub> is a series 2
prostaglandin, synthesized from omega-6 (n-6) fatty acids, which is inhibited
by production of series 3 prostaglandins from n-3 fatty acids. Docosohexaenoic
acid (DHA, 22:6n-3) and
eicosapentaenoic acid (EPA, 20:5n-3) are long-chain n-3 poly-unsaturated fatty
acids (PUFA) that have important biological effects on reproduction through
their involvement in hormone and series 3 prostaglandin synthesis. Ruminant
tissues are naturally almost devoid of n-3 long-chain PUFA, specifically EPA and DHA. Fish oil is the most common ration additive used to provide
very long chain n-3 fatty acids to ruminants. However, marine fish do not
synthesize n-3 fatty acids; they consume microscopic algae or other
algae-consuming fish to obtain n-3 fatty acids. Algae biomass provides a
consistent source of DHA and EPA that could be fed to alter hormonal profiles
and improve reproduction of beef heifers. Eighty-eight Angus × Simmental
heifers (427 ± 1.8 kg) were blocked by BW and allotted to 2 treatments (44/treatment,
4 pens/treatment, 11 heifers/pen). Control heifers were fed a diet that
contained (DM basis) 52.8% mixed grass silage, 32% corn silage, and 15.2%
concentrate. DHAgold™ (49% fat; 21.8% DHA; DSM Inc.) was included in the algae
diet at 1.65% of DM, replacing equal parts of corn and DDGS. Diets were
formulated to contain 12% CP and 0.79 Mcal/kg NEg. Heifers were fed treatment
diets from 54 d prior to the breeding season through the first trimester.
Follicular fluid was collected on day 47 for hormonal analysis. Artificial
insemination (AI) was from d 55 to 98, after which open heifers were removed to
1 control and 1 algae pen and placed with a bull. The study ended on d 180.
Performance data were analyzed using the MIXED procedure and conception data
were analyzed using the GLIMMIX procedure of SAS. Dominant follicle diameter
and follicular estrogen concentration were unaffected by treatment (<i>P</i>≥0.12). Follicular insulin-like
growth factor-1 was greater in algae compared to control heifers (<i>P</i>=0.03).
During the pre-breeding period, algae supplemented heifers had lesser DMI (<i>P</i>=0.006), and greater ADG (<i>P</i>=0.03) during the
breeding period, while BW tended to be greater compared to control heifers on d
98 and 180 (<i>P</i>≤0.07). First service conception rate
did not differ between treatments (<i>P</i>=0.67);
however, second service tended (<i>P</i>=0.08) and overall conception was (<i>P</i>=0.03)
lesser in algae compared to control heifers. These data suggest supplementing
DHA-rich algae improved growth, but decreased conception rates of primiparous
beef females.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12252728 |
| Date | 07 May 2020 |
| Creators | Griffin T Nicholls (8581524) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/EFFECT_OF_SUPPLEMENTING_ALGAE_TO_BREEDING_AND_EARLY_GESTATION_NULLIPAROUS_HEIFERS_ON_GROWTH_AND_REPRODUCTION/12252728 |
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