bump v, hence vbl n bumping
[. . .]
a To detect or test for the presence of (an unborn calf) by pushing on the cow’s flank and feeling for the fetus to rebound; to perform this test on (a cow); also intr, in phr bump for a calf.
1950 Sigel I Fell 193 ME, He tried so hard to bump a calf in Alice that I was afraid he might wear a hole in her side with his daily bumpings. He didn’t feel at all satisfied that Alice was in an expecting state. 1956 Breeder-Stockman 18.44, Although a week past her expected calving date, he was unable to “bump” a calf, the cow showed no signs of “bagging up”, and she was no bigger than normal through the barrel. 2012 DARE File cNY, To find out if a cow is pregnant you “bump calf”—Give the cow a little punch in the side to feel if the calf is there. 2015 in 2017 DARE File—Internet cwCA, A handful of months ago my dairy owner friend bumped her for me and felt a calf move. 2017 Ibid WA, How to Bump for a Calf—“Bumping a Calf” is just what it says—Using a soft fist to nudge the side of a cow’s belly to feel for the shape of a calf inside her around 7–9 months into the gestation. You can also use a soft rocking motion to see if the calf will “bump” back into your fist.
b Hence, of a cow: to prove to be carrying (an unborn calf) when tested in this way; to have (an unborn calf) detectable in this way; also intr. Cf spring n B2
1914 Oxford Gaz. (IN) [20 Mar 8]/5 (newspaperarchive.com), [Advt:] Ages range from 2 to 5 years old, and every one will bump a calf strong today. 1940 Cedar Rapids Gaz. (IA) 25 Feb sec 4 2/8, [Advt:] 1 black Holstein and Guernsey, 6 yrs. old, just ready to go dry, bumping a big calf. 1952 Humboldt Std. (Eureka CA) 19 Jan 12/4, [Advt:] 19 young Jersey and Guernsey cows. Some Holsteins. All bumping calves. 1965–67 DARE (Qu. K10, . . A cow that is going to have a calf) Infs AR4, MS1, She’s bumping; NY13, She’s bumping a calf (when you can feel it); TX37, Bumping a hard calf; [GA9, 12, (She’s) bumping up]. 1973 Winona Sun. News (MN) 18 Feb sec b 15/6, [Advt:] 20 Holstein cows, milking, are bumping calf. 1973 ID Free Press (Nampa) 13 Nov sec A 3/4, [Advt:] Herd Blood Tested, Preg. test on all animals that have not readily bumped a calf. 1983 Janesville Gaz. (WI) 9 Mar sec C 6/3, [Advt:] 58 milk cows. . . 18 are dry and bumping calves or are close springers. Some may be fresh by sale day. 2004 WI State Jrl. (Madison) 18 July sec L 19/5, [Advt:] (14) cows springing or bumping heavy calf, or due within the next 30–60 days. 2013 Eblen–Eblen Betty Bumpers 78 AR (as of 1930s), If a cow was already bred and bumping a calf, he’d take it home until closer to birthing.