The Impacts of Supplemental Protein during Development on Amino Acid Concentrations in the Uterus and Pregnancy Outcomes of Angus Heifers

• Published in: Animals (Basel) Vol. 13; no. 12; p. 1995
• Main Authors: Brandt, Kiernan J, Ault-Seay, Taylor B, Payton, Rebecca R, Schneider, Liesel G, Edwards, J Lannett, Myer, Phillip R, Rhinehart, Justin D, McLean, Kyle J
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.06.2023; MDPI
• Subjects: Amino acids; Animal reproduction; Beef; Body weight; Catheters; Cattle; Composition; Critical components; Dietary supplements; Fertility; heifer development; Hypotheses; Meat production; Nutrition; Pregnancy; Pregnant women; Proteins; Puberty; reproductive efficiency; Semen; supplemental protein; uterine environment; Uterus; United States > US; heifer development; uterine environment; reproductive efficiency; supplemental protein; amino acids
• ISSN: 2076-2615; 2076-2615
• DOI: 10.3390/ani13121995

Replacement heifer development is one of the most critical components in beef production. The composition of the ideal uterine environment could maximize fertility and reproductive efficiency. Our hypothesis was that protein supplementation would affect the uterine environment of beef heifers without inhibiting development or reproduction. To test the effects of dietary supplementation on these outcomes, a randomized complete block design with repeated measures was implemented. Angus heifers ( = 60) were blocked by body weight (BW) and randomly assigned to one of three supplemental protein treatment groups (10% (CON), 20% (P20), and 40% (P40)). Mixed model ANOVAs were used to determine whether protein supplementation treatments, time, and the interaction or protein supplementation, semen exposure, and the interaction influenced uterine luminal fluid (ULF) and pregnancy outcomes. Amino acids (AAs) were impacted ( < 0.001), specifically, the essential AAs: Arg, Iso, Leu, Val, His, Lys, Met, Phe, Trp. Protein supplementation influenced multiple AAs post-insemination: Arg ( = 0.03), CC ( = 0.05), 1-MH ( = 0.001), and Orn ( = 0.03). In conclusion, protein supplementation did not affect the reproductive development via puberty attainment or the timing of conception even with alterations in growth. However, uterine AA concentrations did change throughout development and protein supplementation influenced ULF d 14 post-insemination, which may affect the conception rates.