Vetscore: a new method for nutritional assessment and selection of beef cows to TAI

Reproductive performance of suckled beef cows is directly associated to their nutritional status. Cows with adequate body condition score (BCS) at timed artificial insemination (TAI) are more likely to become pregnant than cows with low BCS. Although the benefits that BCS evaluation may represent in selecting cows for TAI, the method still consists in visual observation and, therefore, subjective. Based on that, the objectives of this study were to: 1) evaluate the relationship between the angle formed between the sides of the rump and BCS; and, 2) develop an objective tool to select cows for TAI according to their nutritional status. In Experiment 1, 801 suckled Nelore cows of 3 to 12 years old and weighing 400 - 625 Kg. All females were evaluated according to their BCS (1 to 5 scale; 1=emaciated e 5=obese; Ferguson et al., J Dairy Sci, v.77, p.2695-2703, 1994). Moreover, the angle formed between the sides of the rump was measured in all cows with a goniometer instrument. All analysis were performed in SAS 9.0 statistical software. The relationship between BCS and the rump angles was analyzed by regression models. There is a positive relationship between BCS and angle of the rump (P 4.25. In this study, 354 Nelore multiparous suckled cows, 4 - 8 years old, were subjected to a TAI protocol (2 mg BE + CIDR at D0 / 2 mL PGF + 300 IU eCG + 1 mg ECP – CIDR at D8 / TAI at 48 h). On D0 all cows were evaluated with the Vetscore and were classified according to its nutritional scale. The pregnancy status was detected with ultrasound 30 d after TAI. Pregnancy rate was analyzed using the Chi-square test. Vetscore presented a precision of 80% and cows classified as Green had higher pregnancy rate than cows classified as Red and Yellow (Pu003c0.01). The pregnancy rates according to Vetscore were 38.6% (51/132), 56.74% (122/215), and 28.6% (2/7), for Red, Green, and Yellow, respectively. These results demonstrate that the new methodology to evaluate nutritional status and select cows for TAI is proven efficient. Therefore, Vetscore device may easily be applied to livestock’s production system.