Conception rates in synchronized beef cows with and without monensin feeding

Area of Science:

• Animal Science
• Reproductive Biology
• Ruminant Nutrition

Background:

• Optimizing beef cow reproductive efficiency is crucial for herd profitability.
• Timed artificial insemination protocols aim to improve conception rates and calving distribution.
• Monensin supplementation is used in cattle diets to alter rumen fermentation and potentially impact performance.

Purpose of the Study:

• To evaluate the efficacy of Syncro-Mate-B (SMB) for timed artificial insemination in Hereford and Hereford crossbred beef cows.
• To assess the impact of monensin supplementation on conception rates and rumen fermentation in these cattle.
• To compare conception rates between SMB-treated and naturally bred control groups.

Main Methods:

• Two groups of Hereford and two groups of Hereford crossbred beef cows were used.
• Cows were assigned to either SMB treatment with timed insemination or natural breeding (controls).
• Monensin supplementation (250 mg/head/day) was administered to one herd of each breed group.

Main Results:

• Overall conception rates were 77% for controls and 84.3% for SMB-treated cows, with no significant difference.
• Conception rates for SMB-timed insemination were significantly lower (P < .10) in Herefords (34.9%) compared to crossbreds (48.5%).
• Monensin treatment did not affect conception rates, but altered rumen acetate to propionate ratios in Herefords.

Conclusions:

• Syncro-Mate-B (SMB) treatment did not significantly improve overall conception rates in this study.
• Breed differences exist in response to SMB timed insemination, with crossbreds performing better.
• Monensin supplementation altered rumen fermentation but did not impact conception rates in the evaluated beef cow populations.