Abstract
This study aimed to contribute to understanding the interface between reproductive and nutritional energetic physiology in contemporary dairy cattle. Multiparous Holstein cows (n = 32) between 70 and 180 days in milk were used in a study starting 10 d prior to the artificial insemination (AI) date and were estrous synchronized using a hormonal regimen. Fourteen cows were determined pregnant on day 39 post-AI. Coccygeal blood samples of all cows were collected on d -10 and -3 prior to AI to determine estrous cyclicity, as well as at AI and at 6, 13 and 20 d post-AI. Milk progesterone was measured 20 d post-AI, and body condition was scored (BCS; 1-5 scale) on days -10, 0, 13 and 27 relative to AI. Blood non-esterified fatty acid concentrations, measured on the same days as BCS, and changes of BCS from d -10 to AI were not predictive of pregnancy outcome. The BCS of cows on the day of AI was greater (P = 0.02) for pregnant cows with an approximate minimum BCS for a high probability of conception being 2.50. Serum progesterone concentrations of pregnant cows were greater (P < 0.05) on days 6, 13 and 20 post-AI, as was milk progesterone at day 20 post-AI (P < 0.01). Pregnant cows had greater (P = 0.02) net energy output (NEL), which is inconsistent with a common belief that low pregnancy rates in contemporary dairy cows are due to excessive milk production, but is consistent with published studies in this study area. The present research indicates that current low pregnancy rates in commercial high-producing multiparous dairy cattle may be partly due to breeding cows that have insufficient BCS to support pregnancy.
| Original language | English (US) |
|---|---|
| Journal | Animal Reproduction Science |
| DOIs | |
| State | Accepted/In press - Jan 1 2018 |
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Keywords
- Body condition score
- Breeding
- Energy balance
- Progesterone
- Reproduction
ASJC Scopus subject areas
- Food Animals
- Animal Science and Zoology
- Endocrinology
Cite this
Effects of long-term, near-term, and real-time energy balance, and blood progesterone concentrations, on the pregnancy rate of contemporary dairy cows. / Gomez, N. A.; Conley, Alan J; Robinson, P. H.
In: Animal Reproduction Science, 01.01.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of long-term, near-term, and real-time energy balance, and blood progesterone concentrations, on the pregnancy rate of contemporary dairy cows
AU - Gomez, N. A.
AU - Conley, Alan J
AU - Robinson, P. H.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - This study aimed to contribute to understanding the interface between reproductive and nutritional energetic physiology in contemporary dairy cattle. Multiparous Holstein cows (n = 32) between 70 and 180 days in milk were used in a study starting 10 d prior to the artificial insemination (AI) date and were estrous synchronized using a hormonal regimen. Fourteen cows were determined pregnant on day 39 post-AI. Coccygeal blood samples of all cows were collected on d -10 and -3 prior to AI to determine estrous cyclicity, as well as at AI and at 6, 13 and 20 d post-AI. Milk progesterone was measured 20 d post-AI, and body condition was scored (BCS; 1-5 scale) on days -10, 0, 13 and 27 relative to AI. Blood non-esterified fatty acid concentrations, measured on the same days as BCS, and changes of BCS from d -10 to AI were not predictive of pregnancy outcome. The BCS of cows on the day of AI was greater (P = 0.02) for pregnant cows with an approximate minimum BCS for a high probability of conception being 2.50. Serum progesterone concentrations of pregnant cows were greater (P < 0.05) on days 6, 13 and 20 post-AI, as was milk progesterone at day 20 post-AI (P < 0.01). Pregnant cows had greater (P = 0.02) net energy output (NEL), which is inconsistent with a common belief that low pregnancy rates in contemporary dairy cows are due to excessive milk production, but is consistent with published studies in this study area. The present research indicates that current low pregnancy rates in commercial high-producing multiparous dairy cattle may be partly due to breeding cows that have insufficient BCS to support pregnancy.
AB - This study aimed to contribute to understanding the interface between reproductive and nutritional energetic physiology in contemporary dairy cattle. Multiparous Holstein cows (n = 32) between 70 and 180 days in milk were used in a study starting 10 d prior to the artificial insemination (AI) date and were estrous synchronized using a hormonal regimen. Fourteen cows were determined pregnant on day 39 post-AI. Coccygeal blood samples of all cows were collected on d -10 and -3 prior to AI to determine estrous cyclicity, as well as at AI and at 6, 13 and 20 d post-AI. Milk progesterone was measured 20 d post-AI, and body condition was scored (BCS; 1-5 scale) on days -10, 0, 13 and 27 relative to AI. Blood non-esterified fatty acid concentrations, measured on the same days as BCS, and changes of BCS from d -10 to AI were not predictive of pregnancy outcome. The BCS of cows on the day of AI was greater (P = 0.02) for pregnant cows with an approximate minimum BCS for a high probability of conception being 2.50. Serum progesterone concentrations of pregnant cows were greater (P < 0.05) on days 6, 13 and 20 post-AI, as was milk progesterone at day 20 post-AI (P < 0.01). Pregnant cows had greater (P = 0.02) net energy output (NEL), which is inconsistent with a common belief that low pregnancy rates in contemporary dairy cows are due to excessive milk production, but is consistent with published studies in this study area. The present research indicates that current low pregnancy rates in commercial high-producing multiparous dairy cattle may be partly due to breeding cows that have insufficient BCS to support pregnancy.
KW - Body condition score
KW - Breeding
KW - Energy balance
KW - Progesterone
KW - Reproduction
UR - http://www.scopus.com/inward/record.url?scp=85039943107&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85039943107&partnerID=8YFLogxK
U2 - 10.1016/j.anireprosci.2018.01.001
DO - 10.1016/j.anireprosci.2018.01.001
M3 - Article
C2 - 29310847
AN - SCOPUS:85039943107
JO - Animal Reproduction Science
JF - Animal Reproduction Science
SN - 0378-4320
ER -