Reproductive Tract Scoring Brendan Kraus, DVM

Heifer Selection Most Cattleman Select Visually Use Size and Appearance Cannot evaluate reproductive traits externally

Age at Puberty Defined as the age of first behavioral estrus (heat) Age of puberty is highly associated with Pregnancy Percentage Percent calving in first 25 days Milk production Heavier progeny weaning weights

Early Conception is the Name of the Game Early calving heifers have higher annual lifetime calf production Are more likely to conceive and calve as 3 year olds Wean a bigger calf Can’t afford to have heifers and 2nd calf heifers drop out of the program

Reproductive Tract Scoring RTS system estimates pubertal status via rectal palpation of the uterine horns and ovaries RTS 1: Infantile tracts RTS 2: Small uterine horns and ovaries RTS 3: Slight uterine tone RTS 4: Good uterine tone, functional ovaries RTS 5: RTS 4 + palpable corpus luteum

Bovine Reproductive Tract

Bovine Repro Tract

Bovine Ovaries

When to Perform RTS? The distribution of RTS for a group of heifers depends on when they are examined If before 12 months of age, most heifers will not be cycling If taken too late, most will receive a 4 or 5 The time of exam depends on the desired use of the system and the particular group of heifers

For Instance, Last minute culling tool Scoring should occur a month or less before breeding. Immature heifers are culled Selection pressure for age at puberty Evaluate when ½ of heifers are cycling based on age, weight, and estrus observation Heifer development check-up 30 to 60 days prior to breeding. Nutritional ration can be adjusted according to findings

RTS 3 vs 4 Heifers scoring 3 at 30 days prior to breeding have up to 20% more opens than heifers scoring 4 or 5 There is considerable expense developing heifers from weaning to pregnancy exam. It is very costly to have them turn up open at this stage

Effects on RTS Age of Heifer Sire genetics Weight/Condition Score Scrotal size Weight/Condition Score Inbreeding

Other Strategies Breed heifers one month before the cow herd Minimally develop heifers and use RTS as a tool to select for inherent fertility and lower maintenance cows

Prepare for Breeding MLV vaccine for IBR/BVD Vibrio/Lepto 7-Way Clostridial Deworm Brand/Ear Tag Pelvic Measure

Pelvic Measure Used as a tool to eliminate small pelvis or those with abnormal shape Used in conjunction with RTS Is not used to select for largest pelvic Utilizes a formula which considers age, weight, and size of calf to deliver Has been shown to allow heifers to deliver 80% unassisted

Questions? * “The Use of Reproductive Tract Scoring in Beef Heifers” Anderson et al CSU Dept of Animal Sciences. Agri-Practice 1991