The aim of this study was to evaluate supplementing linoleic acid to cows during the last two months of pregnancy on transfer of passive immunity to calves. Cows were fed diets formulated to supply minimum amounts of linoleic acid and supplemented without fat, with saturated fatty acids at 1.75 percent of dietary dry matter (DM), or with calcium salts of unsaturated fatty acids enriched in linoleic acid at 2 percent of dietary DM. Within two hours of birth, calves were given 4 liters of colostrum from their own dam or from a dam fed the same dietary treatment as the calf’s dam using an esophageal feeder. Acquisition of passive immunity was assessed by measuring concentration of IgG in colostrum and in serum, as well as total protein concentrations in serum at 0 hours and 24 hours of life.
Apparent efficiency of absorption was calculated considering serum as 9.9 percent of body weight. Body weight at birth did not differ among treatments however calves born from multiparous cows were heavier than those born from primiparous cows (93.7 pounds vs. 81 pounds). Concentration of colostral IgG was greater from multiparous cows fed fat than from those not fed fat prepartum whereas feeding fat to primiparous cows had no effect on colostral IgG.
As a result intake of IgG by calves born from multiparous cows fed fat prepartum was greater than that by calves born to cows not fed fat. Serum concentrations of IgG tended to be greater at 24 hours in calves born from cows fed fat compared with those not fed fat, among fat source, those calves born from cows fed saturated fat tended to have greater serum concentrations of IgG at 24 hours.
Calves born from cows fed fat prepartum tended to be more efficient at absorption of IgG (27.4 vs. 22.9 percent). Recovery rate from diarrhea incidence during the first 15 days of calf age tended to be faster for those calves born from cows fed fat prepartum than calves born from cows fed control diet.
Feeding supplemental fat prepartum to multiparous cows resulted in greater IgG concentration in colostrum, better efficiency of IgG absorption and faster recovery from diarrhea. This research was presented at the American Dairy Science Association meeting in Denver, Colo., this past July.
New research presented by at the American Dairy Science Association annual meeting in Denver, Colo., this past July looked at the effects of free-access feeding acidified milk replacer on pre and post-weaning growth of Holstein replacement heifers and veal calves.
The study was conducted by researchers at the University of Guelph at a commercial dairy operation in central Ontario, Canada. Heifer calves were reared as replacement animals and male calves were marketed as grain-fed veal. Calves were randomly assigned at birth to one of two milk feeding programs: free-access feeding of acidified milk replacer or conventional (3 liters fed twice daily) feeding of milk replacer. Calves were fed milk replacer containing 24 percent crude protein and 18 percent fat. Formic acid was used to acidify the milk replacer for the acid treatment. The target pH for acidified milk replacer was between 4.0 and 4.5.
Calves were gradually weaned from milk replacer at approximately six weeks of age. Body weight, hip width, hip height, body length and heart girth were measured at birth and weaning. A post-weaning body weight measurement was also collected for each calf. There was no difference between the acid and conventional calves for any of the measurements collected at birth. The acid calves had significantly higher pre-weaning body weight gain compared with the conventional calves, as well as greater change in hip width, hip height, body length and heart girth. The acid and conventional calves did not differ for post-weaning weight gain.
These results indicate that free-access feeding of acidified milk replacer supports improved body weight gain and structural growth during the pre-weaning period, but does not affect post-weaning weight gain.
Feed delivery impacts behavior
A new study published in the August Journal of Dairy Science looked at how different feeding methods may affect the learning of feeding and competitive behavior of growing dairy heifers.
Researchers hypothesized that heifers previously fed a total mixed ration (TMR) would distribute their feeding time more evenly throughout the day, compete less for feed, maintain a more solid fecal consistency, and continue to grow rapidly compared with heifers previously fed a top-dressed ration (TDR).
Thirty-two Holstein heifers were divided into eight groups of four and were exposed to one of two treatments for 13 weeks: 1) TMR or 2) TDR. Each treatment contained 65 percent grass/alfalfa haylage and 35 percent textured concentrate on a dry matter (DM) basis.
Following this feeding period, all heifers were switched to an unfamiliar TMR containing 56.1 percent grass/alfalfa haylage, 21.0 percent corn silage, 21.0 percent high-moisture corn, and 1.9 percent mineral supplement (DM basis). Heifers remained on the new treatment for an additional seven weeks.
Group DM intakes were recorded daily throughout the experiment. Feeding behavior, recorded using time-lapse video, and sorting behavior were measured for seven days during weeks one, four, and seven after the dietary change. Feeding competition was measured on days two, four, and six of each recording week. Sorting activity was determined through particle size analysis of the fresh feed and orts. The particle size separator separated feed into four fractions (long, medium, short, and fine). Sorting of each fraction was calculated as the actual intake expressed as a percentage of the predicted intake. Animals were scored for fecal consistency twice weekly, using a scale from one (liquid) to four (solid). Heifers were weighed every two weeks.
Neither DM intake nor average daily gain differed between treatments. Sorting also did not differ between treatments. Heifers tended to spend more time feeding if they had previously been fed a TDR, largely due to the increase in time spent feeding in the two hours following feed delivery. As they had done before the dietary change, heifers previously fed the TDR spent more time at the bunk in the two hours following feed delivery. Heifers previously fed the TDR were displaced from the feed bunk more frequently than heifers previously fed the TMR, particularly during the two hour period following feed delivery. Fecal scores were lower (more fluid in consistency) for heifers originally fed the TDR.
The continued difference in feed bunk competition suggests that heifers previously fed the TDR had learned these patterns when fed the TDR, retaining them even when switched to an unfamiliar ration. Furthermore, lower fecal scores for heifers previously fed the TDR suggest altered rumen fermentation, possibly because of altered daily consumption patterns. These results show that feeding a TMR to replacement dairy heifers from a young age promotes a more even daily feeding pattern, minimizes feed bunk competition, and promotes a more solid fecal consistency.
Source: Journal of Dairy Science
