Transit factors affecting shrink, shipping fever and subsequent performance of feeder calves.

Five shipments of feeder calves (965 head hauled in 11 drop-center trailers) were shipped 1,600 km by tractor trailer from Algood, Tennessee, to Bushland, Texas, during the fall seasons of 1976, 1977 and 1978. Shrink, incidence of shipping fever and subsequent feedlot performance of these feeder calves were analyzed. There were significant differences in shrink and subsequent feedlot performance between calves shipped on different dates. In only one instance was there a significant difference in shrink between trucks of steers shipped on the same date, and this was due to a difference of in-transit time between trucks. There were no significant differences in shrink, incidence of shipping fever of feedlot performance between calves shipped in different trailer compartments, nor were there any interactions between shipping dates and trailer compartments for shrink, incidence of shipping fever and feedlot performance. The number of calves treated for shipping fever did not differ significantly among trailer compartments, but did differ among shipment dates. Significant differences in morbidity between shipping dates indicate that the incidence of shipping fever is apparently affected by environmental conditions before, during and immediately after transit. The results indicate that multiple truckloads of calves, if traveling together, can be treated as a single unit for the statistical analysis of shrink, incidence of shipping fever and feedlot performance.

Effect of drinking water temperature on heat stress of dairy cows.

Experiments were to determine the effectiveness of chilled drinking water in reducing heat stress of lactating dairy cows. Using a 4 X 4 Latin square statistical design, 16 cows (4/treatment) were deprived of water from 0800 until 1400 h at which time they were given chilled water (10, 16, 22 degrees C) or a control water (28 degrees C) ad libitum. Cows were rotated weekly among treatments. Eight of the cows (2/treatment) were selected at random and monitored continuously for body temperature measured in the middle ear near the tympanic membrane. The coldest water (10 degrees C) reduced body temperature (.75 degrees C) more than 28 degrees C water (.46 degrees C). The coldest water also reduced respiration rate and kept body temperatures lower longer. Chilled water was only about 32% effective in reducing body temperature, and it is doubtful if the effect was prolonged enough (about 2 h) to keep the body temperature of cows from rising above the critical temperature of thermoneutrality. Offering chilled water at milking time may provide an incentive for the cows to enter the milking parlor.

Effects of drinking water temperature on physiological responses of lactating Holstein cows in summer.

Nine lactating Holstein cows were offered drinking water of 7.2, 15.6, and 23.9 degrees C in a 3 X 3 Latin square design in Experiment 1. Water was offered for 10 min at 1300 h to simulate time in a milking parlor. Water consumption declined as drinking water temperature decreased. Respiration rates decreased as the drinking water temperature decreased. In Experiment 2, 8 lactating Holstein cows were offered water of 12.8 and 26.7 degrees C in a 2 X 2 changeover design. Results were consistent with Experiment 1. In experiment 3, 16 lactating Holstein cows were offered drinking water of 10, 16, 22, and 28 degrees C in a 4 X 4 Latin square design. Water was offered for 10 min at 1400 h. Respiration rates and deep rectal temperatures were taken before and after watering. Water consumption declined as drinking water temperature decreased, but the cooling effect of the low temperature water was greater. Lower drinking water temperature decreased respiration rates postwatering. Deep rectal temperatures were not affected as drinking water temperature decreased. Both respiration rates and deep rectal temperatures began to increase within 40 min after watering, indicating a transient cooling effect of the chilled water.

Effects of drinking water temperature on production responses in lactating Holstein cows in summer.

During late summer, 24 lactating Holstein cows were offered 10 or 28 degrees C (control) drinking water ad libitum at 1400 h for 10 min to investigate the effects on respiration rates, body temperatures, dry matter intake, and milk production. Experimental design was a 2 X 3 factorial arrangement of the two drinking water temperatures with .8, 1.1, and 1.4% dietary potassium associated with another experiment. Following 1 wk adjustment and 1 wk standardization, cows were blocked by dry matter intake as a percentage of body weight within parity and randomly assigned to treatments within blocks. Cows were denied access to water from 0900 until 1400 h. Respiration rates and rectal temperatures were recorded before and after watering. Tympanic membrane temperatures (8/h) were recorded during the comparison period using 4 cows per water treatment. No interaction occurred between water and potassium. Water at 10 degrees C had a greater cooling effect than 28 degrees C water. No differences were found between treatments in respiration rates and rectal temperatures after drinking water was temperatures after drinking water was offered. Chilled drinking water decreased tympanic membrane temperatures, which remained lower longer. Cows that drank 10 degrees C drinking water increased dry matter intake and milk yield.

Responses of lactating Holstein cows to chilled drinking water in high ambient temperatures.

In Experiment 1, 12 lactating Holstein cows were provided drinking water of either 10.6 or 27.0 degrees C for 24 h/d in a changeover design to examine the effects of water temperature on feed intake, water intake, respiration rate, rectal temperature, plasma thyroid hormone concentration, and milk yield. The 1st wk of each 3-wk treatment period was for adjustment and the next 2 wk were comparison periods. Least squares means for DM intake as a percentage of body weight were 3.68 and 3.57 for 10.6 and 27.0 degrees C treatment groups. Water intakes in liters per kilogram of dry feed consumed as a percentage of body weight were 21.3 and 20.3. Respiration rates were 70.5 and 81.0 breaths per minute; rectal temperatures were 39.7 and 39.9 degrees C, Triiodothyronine averaged .88 and .75 ng/ml; thyroxine, 42.4 and 39.2 ng/ml; cortisol, 3.03 and 2.06 ng/ml; and progesterone in milk, 4.58 and 3.15 ng/ml for the 10.6 and 27.0 degrees C treatment groups. Milk yield averaged 25.9 and 24.7 kg/d and FCM averaged 25.6 and 23.6 kg/d, respectively. In Experiment 2, 24 cows given a choice of chilled or warm water showed a clear preference (about 98%) for the warm water. If cows are given chilled water of 10 degrees C continuously, no warm drinking water should be available. Chilled drinking water lowered respiration rates and body temperatures and increased feed intake and milk yield.

Chilled drinking water effects on lactating Holstein cows in summer.

In Experiment 1, 12 multiparous lactating cows (six per group) were offered drinking water ad libitum at temperatures of 10 or 30 degrees C in a switchback design. The treatment group received 10 degrees C water from 1235 to 2000 h and was then changed to 30 degrees C water for the remaining 16.5 h/d. The control group received 30 degrees C water 24 h/d. Respiratory rates, rectal temperatures, and rumen motilities were measured at 1100, 1440, and 1810 h, 3 d/wk. Water consumed was recorded for 1235 to 2000 h and 2001 to 1234 h of the next day. Water consumption for the treatment group was 3.90 L/h per cow compared to 5.40 L/h per cow for the control group from 1235 to 2000 h. However, the 10 degrees C water absorbed 65.6 kcal/h more heat than the 30 degrees C water. No differences were found in respiratory rates, rectal temperatures, rumen motilities, or milk yield. Cows that drank 10 degrees C water consumed 3.67 kg of feed DM/100 kg of body weight compared with 3.36 kg of feed for the controls. In Experiment 2, the same two groups of cows were offered 9.5 degrees C water ad libitum for 24 h/d or 27.5 degrees C water for a 48 h comparison. The treatment group tended to consume more water than the control group and to have lower respiratory rates and body temperatures.