Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/1995
Publication Date: N/A
Citation: Interpretive Summary: To the cow-calf producer reproductive efficiency and calf weaning weights are the most important factors determining profitability. Of the cow herd, first calf heifers have the lowest conception rates and the lightest calves. Early weaning and restricted suckling by calves have increased conception rates, but the effects of these strategies on calf performance are variable. Determinants affecting calf weights appear to be quality of forage available to the calf and the length of time suckling is restricted. Studies examining this relationship were conducted on improved pastures. This study was designed to determine the effect of restricted sucking on calves raised under two differing New Mexico range sites. Calves raised in either shortgrass prairie or mountain pastures were prevented from suckling the rear quarters for 14 days at 48 days of age. These calves weighed less than calves allowed to suckle all four quarters when weighed immediately after the restriction period, but weight differences were not observed afterwards. However, calves restricted from suckling the rear quarters for 28 days had lower body weights after the restriction period that persisted until weaning. Restricting suckling did not affect weight changes of the cow or the forage intake of the cows or calves. This suggests that under either set of range conditions calves did not compensate for lower milk intakes by increasing forage intake.
Technical Abstract: Twenty 2-year-old primiparous Angus x Hereford cows and their heifer calves were used to study effects of partial suckling restriction on cow and calf performance. Ten cow-calf pairs were allotted to two treatments at Fort Stanton, NM. Calves from five cows were prevented from suckling the rear udder quarters for 2 weeks (Restricted, RES) when calves were 48 +/- 4 days sof age. The other five cow-calf pairs served as controls (CON). Average daily gain (ADG) of RES calves was less (P <.05) than CON calves during restriction, but was not different (P >.10) on any subsequent date. Likewise, cow ADG, calf body weight (BW) and cow BW were not different (P >.10) at any time. The experiment was repeated at Clayton, NM, except that calves (52 +/- 4 days of age) were restricted for a total of 28 days and four 12-day grazing trials were conducted from June through September. Calves from the CON group weighed more (P <.05) in each trial and averaged greater (P <.05) ADG than RES calves during the restriction period and at weaning. Calves from the RES group did not (P >.10) suckle longer or more frequently than CON calves during any trial. Forage Organic Matter (OM) intake and fluid passage rate were not (P >.10) different between cows or calves from either group at any date. Milk production was not different (P >.10) between groups one month after restriction periods were terminated at either location.