Freshening the First Calf Heifer
The first-calf heifer must successfully adapt to numerous physiological and behavioral changes at calving. Strategies that reduce stress prior to calving should optimize the chance for success, says Noah Litherland, Dairy Nutritionist, University of Minnesota, Dairy Extension.
Stress reducing strategies should focus on adaptive nutrition and behavioral management prior to calving, According to the USDA, first-calf heifers represent approximately 36 per cent of the U.S. cow population. First calf heifers represent the present and the future of dairy farms.
Improvements in transition programs for first calf heifers will have an effect on herd performance today and in subsequent lactations. Strategies that promote favorable energy balance, reduce negative social and behavioral interactions, and reduce health challenges may improve profitability.
Opportunities for improvement exist even on well managed herds. A large (n = 1905) heifer field study conducted in California (Ettema and Santos, 2004) showed that culling after calving and mortality averaged 17.6 per cent and 3.9 per cent, respectively. Disorders reported included: mastitis (19.4 per cent), lameness (15 per cent), and left displaced abomasum (2.9 per cent).
Overfeeding energy to first calf heifers prior to calving appears to be detrimental to health. Researchers in Wisconsin found that heifers fed a moderate energy diet prepartum had higher DMI postpartum than heifers fed greater amounts of energy (Grummer et al., 1995). Higher energy feeding prepartum did not improve milk yield, resulted in higher blood non-esterified fatty acids and β-hydroxy butyrate, and tended to increase liver triglycerides.
These measurements suggest that feeding excessive energy prior to calving results in greater negative energy balance after calving. Another Wisconsin study determined that feeding pregnant first calf heifers low-energy/high fiber diets may help control energy intake and minimize overconditioning at calving (Hoffman et al., 1996).
More recently, an Illinois study showed that heifers fed excessive energy prior to calving tended to have lower DMI postpartum than those fed a high forage moderate energy diet (Janovick Guretzky, 2006). Therefore, keep in mind that overconditioning increases risk for excessive body fat mobilization, which reduces energy intake postpartum and predisposes heifers to metabolic disorders.
First calf heifers must adapt to co-mingling with older socially dominant cows, learn to use head locks and freestalls, become accustomed to increased handling by humans, and adjust to the milking routine. Interesting data from Spain showed total eating time was longer when primiparous (first-calf heifers) cows were housed with multiparous (two or more freshenings) cows; however, primiparous cows housed alone ate almost one more meal per day than those housed with multiparous cows (Bach et al., 2006).
Feeding area for cattle co-mingled by parity was limited to one feeder per 1.8 cows; however, more than 50 per cent of the feeders at time of feeding were occupied by primiparous cows, suggesting they were not intimidated by multiparous cows. Housing heifers and cows separately does, however, offer several advantages including: matching stall size, reducing negative social interaction, and feeding to more closely meet nutrient requirements.
Smooth return from the heifer grower
Whether heifers are raised by the owner or farmed out to a heifer grower, a smooth transition into the milking herd is important to the success of the first and subsequent lactations. Variables such as avoiding overconditioning, calving at an appropriate age and size, and experience with the use of headlocks and freestalls are important factors. Norwegian researchers evaluated proper freestall use by heifers transferred from heifer growers back to the milking herds. On day 2 after transfer, 34 per cent of the heifers refused to use freestalls and by day 15, there will still 23 per cent of the heifers exhibiting this behavior (Kjoestad and Myren, 2001). Allowing heifers adequate time to adapt to their new surroundings in the milking herd may have some impact on transition success.
Reducing udder edema in first calf heifers
Udder edema is a disorder characterized by excessive accumulation of fluids in the intercellular tissue spaces of the mammary gland. Challenges with udder edema have been attributed to genetic predisposition, feeding excessive grain, and mineral imbalances (excessive sodium and potassium). Prepartum nutrition strategies such as selecting forages low in potassium and reducing sodium intake may help reduce udder edema.
Prepartum exercise for primiparous cows?
Exercising close-up heifers has become a standard on some dairy farms. Researchers at Michigan State exercise-trained cows on a treadmill and determined that exercise reduced heart rate in responses to stress and muscle fitness to reduce response to fatigue (such as at calving) (Davidson and Beede, 2009). Responses in exercised first calf heifers might be similar.
We must continue to be vigilant in our quest for improved performance, health, and well-being of our dairy cattle. Areas where opportunities for improvement exist, such as optimal management of first calf heifers, should not be overlooked. A high degree of variability is inherent in transition cows often shrouding solutions to transition cow failures. Feeding strategies that work for both primiparous and multiparous cows should be considered.