Is Supplemental Feeding Necessary for Fawn Production? - Part II
Does Supplemental Feeding Improve Fawn Production Or Survival?
Supplemental feeding is mandatory if you wish to maximize the number of deer on your ranch. Fawn production and survival much like antler growth are directly related to nutrition. If nutrition is limiting for pregnant does, especially late in pregnancy (May-July), fawn production will be reduced. If nutrition is limiting for lactating does during July-September, fawn survival will also be negatively affected.
The first scientific study on supplemental feeding in south Texas, by Bob Zaiglin and Dr. Charles DeYoung at Texas A&I University (now Texas A&M University-Kingsville), clearly showed the positive effects a supplemental feeding program can have on fawn crops. The study was conducted on the Zachry Blanco Ranch south of Laredo in Webb County during 1976 and 1977.
These researchers divided the ranch in half by using one pasture as the control area where supplemental feed was not provided. The second pasture served as the treatment area. Four feeder sites were established in this pasture and supplemental feed was provided from February, 1976 through January, 1977. The second year of the study, the feeders were moved to the other pasture to reverse the control and treatment areas.
During helicopter surveys in October of each year, they counted a significantly higher ratio of fawns in the supplemental-fed pastures (0.39 fawns per doe in the supplemented pasture vs. 0.20 in the control pasture during 1976 and 0.24 fawns per doe in the supplemented pasture vs. 0.08 in the control pasture during 1977). The researchers concluded that (1) supplemental feeding significantly increased fawn survival; (2) deer ate 0.55 pounds of supplemental feed per minute; (3) bucks fed for an average of 2.4 minutes (1.3 lbs.) per visit; and (4) does fed an average of 2.9 minutes (1.6 lbs.) per visit.
Graduate student Mark Richman and his co-workers and professors at the Caesar Kleberg Wildlife Research Institute at Texas A&M University-Kingsville studied the effects of supplemental feeding on fawn weights. They weighed 42 fawns contained within both supplemental-fed and non-fed 200-acre enclosures. The researchers found that supplemental feeding resulted in fawn weights that were 14 to 47% higher than weights of fawns from enclosures where supplement was not provided. Interestingly, fawn weights were lowest in the enclosure with the highest deer density and highest in the enclosure with the lowest deer density.
The two Michigan researchers mentioned above, John Ozoga and Louis Verme, also found that supplementation greatly increased deer numbers, by improving both fawn production and survival, and by increasing buck survival during the post-rut.
Feeding Fawns and Does
Unfortunately, fawn production and survival could no doubt be further improved with supplementation if it were easier to get feed to fawns and does. At typical feeder densities of around one feeder per 200 to 500 acres, few if any fawns will access feeder sites. This is especially true if the feeder sites are fenced to exclude feral hogs and javelinas. Relatively few does will access these sites as well if timed-release feeders are used due to buck dominance at this style of feeder.
A recent study in Colorado involving mule deer supports the above concerns. Chad Bishop and his co-workers fed manufactured protein pellets to deer during winter and spring only, by placing the pellets directly on the ground in two-to-three-pound piles spread out along primitive roads within the study area. They reported that survival rates of fetuses and newborn fawns, overwinter survival of older-aged fawns, and adult doe survival all increased as a result of the supplemental feeding.
When Is The Best Time To Feed?
The short answer, in south Texas at least, is that supplemental feed should be provided year-round. A supplemental feeding program should be designed to cover two different stress periods. The first stress period is based on the native habitat and occurs whenever 