Tramped Teats – Clinical Mastitis Disease Complex in Tied Cows. Environmental Risk Factors and Interrelationships with Other Diseases

The effects of stall length, manure system, type of bedding and calving disorders on incidence rates of tramped teats, udder injuries, and clinical mastitis in Swedish Red and White tied cows, as well as interrelationships between these 3 disorders were investigated. Data used consisted of 370 herds, for a total of 45,133 cow records. Cows in herds with liquid manure system were at hihger risk of udder injuries and mastitis than in herds with solid system. Lower risk of both udder injuries and mastitis was found for cows in herds with short stall size (< 180 cm) compared to herds with stalls of 205–219 cm length. It was suggested that other factors, such as slipperiness of the stall floor and presence and type of feeding barrier, must be considered when the effect of stall characteristics on tramped teats is investigated. In farms with solid manure system cut straw or sawdust bedding increased the risk of tramped teats and mastitis relative to uncut straw. Parity and calving disorders were important risk factors for udder health and their effect was greater in herds with liquid manure system. Tramped teats and udder injuries were the most serious risk factors for clinical mastitis.     

Action of androgen and estrone implants on sexual behavior and reproductive organs of castrated male rabbits

Sexually mature but inexperienced male rabbits were castrated, immediately implanted with either testosterone (T), estrone (E₁), dihydrotestosterone (DHT), T + E₁, or DHT + E₁, and tested for male sexual behavior. Other castrates were not implanted, and testing was either begun immediately (Ca-I) or delayed for 4 weeks (Ca-D). Intact males served as controls (C). Latency to mount a teaser female and to ejaculate into an artificial vagina was tested twice in a morning three times per week for 8 weeks. Then, animals were sacrificed, and reproductive organs were measured. The Ca-I group responded slowly to sexual training and ceased nearly all sexual activity by 8 weeks, whereas the Ca-D males seldom displayed interest in the teaser female. Intact controls and the T and T + E₁, groups all responded to the teaser and mounted and ejaculated within a few seconds. DHT and E₁, individually maintained the sexual activity of castrates equivalent to that of C for 4–5 weeks, but the time required to mount and, particularly, to ejaculate increased thereafter. The results with DHT + E₁ were equivocal in that castrates with this hormone combination sustained sexual activity equivalent to that of the controls for 7 weeks, but one animal in particular became sexually inactive the last week of the experiment. Penis weight was at least partially maintained in all implanted castrates. Accessory sex gland weight was smallest in the DHT group and was significantly increased in the T + E₁ and DHT + E₁ groups. The largest ejaculates of fluid were obtained in the group receiving E₁ alone. These results may be interpreted to indicate a role of both androgen and estrogen centrally and peripherally in the rabbit.     

Case-referent study of cystic ovaries as a risk indicator for twin calvings in dairy cows

The association between cystic ovaries and twin births in dairy cows was analyzed in an epidemiologic study. The case-referent study design was chosen. The cases were all twin-bearing cows during the observation period. Two different groups of cows giving birth to single calves were used as controls. One group consisted of cows from the same herds as the twin-bearing cows; the second group consisted of cows randomly selected from the entire population. The frequency of cystic ovaries was significantly higher in control cows from herds with twin-bearing cows than in control cows randomly selected from the general population. This finding suggests an indirect association between the occurrence of cystic ovaries and the birth of twins. The direct association between cystic ovaries and birth of twins was evaluated by odds ratio. The magnitude of this measure varied according to breed and the control group used for calculation. A biological explanation for this finding could be that the frequency of intrauterine death and resorption of one twin fetus differs among breeds and cows with or without a history of cystic ovarian disease.     

Importance of inseminating only cows in estrus

Reproductive efficiency is a key component in successful dairy farm management. A study was initiated to evaluate the incidence and consequences of inseminating dairy cows in the middle of the estrous cycle or while pregnant. In a research herd of 242 Holsteins, managed for reproduction under typical farm conditions, milk progesterone (P4) was assayed 3 times per wk for at least 120 d postpartum. The P4 cycle was compared with the estrus detection and breeding records and pregnancy diagnosis 6 wk after insemination. About 19% of the inseminations were performed when P4 was high in the estrous cycle and in pregnant cows. Insemination of pregnant cows led to an estimated 17% induced embryonic death or abortion. In Israel, inseminators are extensively trained to detect cows not in estrus. They reject about 16% of the cows submitted for reinsemination, with a 95% accuracy of rejection of 44% of the cows that were pregnant. The pattern of submission of cows for reinsemination in areas around New York State was similar to Israel and to the experimental herd. These results indicate that more careful submission and rejection can reduce the unnecessary use of semen, reduce abortions and minimize long calving intervals, all contributing to the success of a dairy herd operation.     

The behavioral responses in ovariectomized cattle to either estradiol,testosterone, androstenedione,or dihydrotestosterone

Steroid hormone effects on sexual behavior were measured in 15 sexually mature nulliparous cattle which were bilaterally ovariectomized. They were alloted at random to five groups of three animals each (sesame oil vehicle control, estradiol, testosterone, androstenedione, and dihydrotestosterone) in the fall of the year and reassigned at random to replicate the study the following spring. Each experiment was divided into three weekly trials. Animals within treated groups were reassigned each week to receive in random order one of three levels of a particular hormone (200, 400, and 800 μg of estradiol and up to 1000 times these doses of androgens).Estradiol, and to a lesser extent, testosterone were capable of increasing the frequencies of occurrence of most behavioral parameters studied. These were: (1) elicitation of vulval interest; (2) vulval sniffing; (3) agonistic interactions; (4) giving chin rests; (5) receiving chin rests; (6) attempted mounts; (7) successful mounts; and (8) standing when mounted. The mean interval from treatment to first standing to be mounted was 25.4 ± 0.8 and 33.3 ± 5.2 hr for the estradiol-treated and testosterone-treated heifers, respectively. Peak activity generally occurred the second day after initiation of hormone treatment and rapidly declined after the third day. Flehmen lip curl and bellowing were not stimulated by either hormone. Neither androstenedione nor dihydrotestosterone was capable of stimulating sexual behavior in these heifers, as measured by any of the parameters studied.