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The purpose of this study is to characterize the thermoregulatory responses of unrestrained heat-stressed dairy cows within a freestall environment using fan and spray configurations for cooling cows while lying or standing. An experimental treatment sprayed individual cows lying in freestalls from 11:00 to 15:00 (stall cooling period) during hot-humid weather (average THI of 82.4) over a five-day trial period, using ultrasound transceivers to detect their presence. Core body temperatures were continuously monitored with vaginal temperature loggers. To assess behavioral responses, cows were visually monitored during the stall cooling period. Respiration rates and dorsal surface temperatures were recorded when the cow lay down or stood up in a stall. Core body temperature of lying cows rises at a rate of 0.6°C h-1 when exposed to fan cooling alone. Adding spray cooling to fan cooling slows the rate of rise to 0.3°C h-1. With or without freestall spray cooling, cows stand and seek cooling when their core body temperatures reach 38.9°C. Core body temperature is a more reliable indicator than either dorsal skin temperatures or respiration rates for predicting when cows stand and seek cooling. Core body temperatures of cows fall at a rate of 0.7°C h-1 while standing under feed line spray and fan cooling, while core body temperatures of cows standing under fans without spray remain unchanged. To cool heat-stressed cows, water spray is required in addition to fans while the cows are standing. Fans alone are inadequate. [ABSTRACT FROM AUTHOR]

Glycosaminoglycans (GAG) promote acrosome reactions (AR) in bovine and rabbit spermatozoa in vitro. Female bovine reproductive tract secretions contained GAG and the concentrations and composition of those GAG varied with different regions and stages of the estrous cycle. This study was designed to evaluate the types of GAG found in reproductive tract secretions of ewes at different stages of the estrous cycle and the ability of the secretions to promote AR. Ewes (n=48) were slaughtered at 0, 12, 24, 36,72 and 144 h following observations of standing estrus. Reproductive tracts were flushed with a modified Tyrode's medium (TALP; 7 ml) not containing calcium. Concentrations and composition of GAG in the tract were determined by high performance liquid chromatography. Concentrations of GAG decreased anterior to the cervix: 2.28 to .74 mg/100 mg protein (P<.05). Increases in heparin-like GAG during the estrual phase and chondroitin sulfate GAG during the luteal phase were noted. Bovine sperm were incubated in tract flushings standardized to contain 4 µg/ml of GAG and supplemented with calcium. Sperm incubated in estrual flushings for 9 h exhibited a higher incidence of AR than those incubated in luteal flushings or control, 50% vs 36% and 29%, respectively (P<.0001). It is concluded that during the estrous cycle there were changes in concentrations and composition of GAG in ewe reproductive tracts and the potencies of those female secretions causing AR varied.

Concentrations of progesterone in uterine and arterial tissue and in uterine and jugular venous plasma were determined. Blood was collected on Days 4 and 9 postestrus from the jugular vein and the first and last venous branches draining each uterine cornu; uterine tissue and arteries were subsequently collected. Progesterone was greater (p<0.05) in the cranial third than in the middle or caudal thirds of the uterine horn adjacent to the corpus luteum (CL)-bearing ovary or in any third of the contralateral horn. Progesterone in uterine arterial segments adjacent to the CL-bearing ovary was higher (p<0.05) than in contralateral segments. Progesterone was higher (p<0.05) in blood from the first venous branch of the cranial third of the uterine cornu adjacent to the ovary with the CL, than in the last branch of the caudal third, or contralateral horn, or in jugular blood. When oviductal veins were resected on Day 9 postestrus, progesterone in the first vein draining the cranial third of the uterine cornu adjacent to the CL-containing ovary was not different (p>0.05) 48 h after resection than in the same vessel in the opposite horn or in jugular blood. We concluded that progesterone and other ovarian products may be delivered to the uterus locally.

Our previous work confirmed the excellent activity of CuO−MoO3/Al2O3 for the destructive oxidation of (CH3)2S2. This study further investigates the effect of acid treatment on the performance of this catalyst. Four different kinds of inorganic acids (HCl, H2SO4, HNO3, H3PO4) are used to treat the γ-Al2O3 support before impregnating it with copper and molybdenum metal salts. The prepared catalysts are then used for the destructive oxidation of (CH3)2S2. Experimental results indicate that HCl-treated and H2SO4-treated catalysts exhibit a higher activity than those without acid treatment. In addition, the H2SO4-treated catalyst (CuO−MoO3/Al2O3−SO4^2-) displays the best stability. As BET surface area analysis demonstrates, the surface area and average pore diameter of the H2SO4-treated catalysts are larger than those without treatment; however, the increase in surface area is not the main factor in promoting the activity. XRD analysis reveals that the CuO−MoO3/Al2O3−SO4^2- catalyst also has the crystalline structure of Cu3Mo2O9 and CuMoO4 which have been found in CuO−MoO3/Al2O3 and which might play a prominent role in the catalyst activity. XPS and TGA analyses suggest that it might have the functional group of SO4^2- which exists on the surface of the CuO−MoO3/Al2O3−SO4^2- catalyst. The NH3-TPD pattern shows that the acidity is remarkably enhanced when the catalyst is treated with an H2SO4 solution. We believe that the substantial increase in activity is attributed primarily to the presence of the SO4^2- group and the formation of a copper molybdenum oxide phase on the catalyst surface.

Early weaning of calves from anestrous cows results in formation of short-lived corpora lutea (CL) unless the animals are pretreated with a progestagen (norgestomet). This study was conducted to investigate the relationship between pre- and post-ovulatory gonadotropin secretion and luteal lifespan. Postpartum beef cows were assigned randomly into two groups, control (n = 5) and norgestomet (implant given at weaning for 9 d; n = 7). Calves from all cows were weaned 30 to 33 d postpartum. Coccygeal artery cannulas were placed into cows in the control group 1 d prior to weaning and 2 d before implant removal in cows in the norgestomet group. Plasma for determination of luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol-17β (E) and progesterone (P) was collected daily at 10-min intervals for 6 h from weaning (control) or the day prior to implant removal (norgestomet) to estrus (d 0) and on d 2, 4 and 6 following estrus. Average interval (x̄ ± SE; P<.05) from weaning to estrus or implant removal was 4.2 ± .8 and 2.3 ± .2 d for the control and norgestomet groups, respectively. Estrous cycle length for the control group was 12.4 ± 1.8 d compared with 20.4 ± .3 d for the norgestomet group (P<.05). Four of five control cows had an estrous cycle length of 7 to 14 d; all cows in the norgestomet group and the remaining control cow had an estrous cycle of normal length (16 to 21 d). Mean concentrations and frequency, amplitude and duration of pulses of LH and FSH were not different between cows having short estrous cycles (control) and cows having a normal estrous cycle (norgestomet implant) 1, 2 or 3 d prior to first estrus and on d 2, 4 and 6 following first estrus. Concentrations of E were higher (P<.05) the day of estrus for the norgestomet group (9.9 ± 2.2 pg/ml) than for the control group (5.7 ± .8 pg/ml). We conclude that subnormal luteal function does not appear to be due to inadequate gonadotropic stimulation during either the pre- or post-ovulatory period.