Path analysis and logistic regression were used to model direct and indirect relationships among clinical periparturient (within 30 d after calving) retained placenta, metritis, veterinary-assisted dystocia, uncomplicated and complicated ketosis, left displaced abomasum, parturient paresis, mastitis, and estimated nutrient intakes (protein, calcium, phosphorus, energy; coded into terciles) in the last 3 wk of the dry period. Data were from 1,374 multiparous Holstein lactations for calvings from March 1981 through February 1982 in 31 commercial herds in central New York. Periparturient disorders occurred as a complex. Odds ratios for the multiplicative effects of parturient paresis on incidence of veterinary-assisted dystocia, retained placenta, complicated ketosis, and clinical mastitis were 7.2, 4.0, 23.6, and 5.4, respectively. Reproductive disorders were interrelated. Retained placenta, left displaced abomasum, and parturient paresis directly increased risk of complicated ketosis (odds ratios were 16.4, 53.5, and 23.6, respectively). Higher terciles of estimated energy intake in the last 3 wk of the dry period decreased risk of veterinary-assisted dystocia and left displaced abomasum, while higher terciles of estimated protein intake decreased risk of retained placenta and uncomplicated ketosis. Estimated nutrient intakes were directly related to subsequent metabolic disorders and directly and indirectly related (mediated by metabolic disorders) to reproductive disorders. The study suggests that feeding higher intakes (relative to National Research Council recommendations) of protein and energy in the last 3 week of the dry period may reduce the incidence of metabolic and reproductive disorders. Exact recommendations as to the amounts and types of feed cannot be made from our results.

Medical records of 210 horses that survived ventral midline celiotomy for at least 4 months were examined and owners were queried to determine factors contributing to incisional hernia formation. The incidence rate of incisional hernias within 4 months was 16%. Factors significantly associated with occurrence of incisional hernias were incisional drainage, closure of the linea alba with chromic gut suture material, previous midline celiotomy, excessive incisional edema, castrated male sex, postoperative leukopenia, and postoperative pain (colic). Factors not significantly associated with occurrence of incisional hernias were suture pattern used for linea alba closure, concurrent enterotomy or intestinal resection, postoperative bandage or stent, postoperative fever, hypoproteinemia, diarrhea, respiratory disease (coughing), and peritonitis. Hernias developed in horses within 12 weeks of surgery, with the earliest hernia recognized at week 2. Of 30 horses for which information was available, only one hernia developed in 24 (80%) and two or more hernias developed in 6 (20%) along the incision. Multiple hernias tended to be smaller than single hernias.

The relationship of body condition score with disease occurrence was examined in 561 cows in nine herds. Cows were body condition scored on a five-point scale (1 = thin, 5 = obese) every 2 wk from drying off until 150 d in milk. Cows scored between 3- and 3+ were considered to be in average or good condition. Cows scored less than or equal to 2+ were considered to be underconditioned, whereas those scored greater than or equal to 4- were considered to be overconditioned. Relationships of health and condition score were examined using multiple logistic regression for dichotomous outcomes (e.g., diseased or healthy). Cows that developed dystocia or were culled lost more condition during the dry period than those that did not develop dystocia or were not culled. Cows overconditioned at drying off were more likely to develop cystic ovarian disease and reproductive problems. Cows underconditioned or overconditioned at drying off were more prone to foot problems after calving. Cows overconditioned at 30 d postpartum were more likely to have metritis.

Forty-eight Holstein cows with two or more previous lactations and no history of parturient paresis were randomly assigned to one of four prepartum diets in a 2 x 2 factorial design to determine the effect of dietary supplementation with ammonium salts and Ca intake on serum Ca concentrations at calving. Four diets provided either 53 g total dietary Ca/d or 105 g Ca/d and were either supplemented with ammonium salts [100 g/d each of NH4Cl and (NH4)2SO4] or unsupplemented. Anion-cation balance of the diets, calculated as milliequivalents (Na + K)--(Cl + S), was -75 meq/kg DM with ammonium salts and +189 meq/kg DM without ammonium salts. Experimental diets were fed from 21 d prior to expected parturition until calving. Calcium intake during the feeding period did not affect the incidence of parturient paresis or serum concentrations of ionized Ca at calving. The incidence of parturient paresis was 4% with and 17% without the ammonium salts. Cows fed diets containing ammonium salts had higher serum ionized and total Ca concentrations at parturition. Serum concentrations of Mg, P, Na, K, and Cl on the day of parturition were unaffected by dietary treatment.

:  Many riparian zones in the Sonoran Desert have been altered by elimination of the normal flood regime; such changes to the flow regime have contributed to the spread of saltcedar (Tamarix ramosissma Ledeb.), an exotic, salt‐tolerant shrub. It has been proposed that reestablishment of a natural flow regime on these rivers might permit passive restoration of native trees, without the need for aggressive saltcedar clearing programs. We tested this proposition in the Colorado River delta in Mexico, which has received a series of large‐volume water releases from U.S. dams over the past 20 years. We mapped the vegetation of the delta riparian corridor through ground and aerial surveys (1999–2002) and satellite imagery (1992–2002) and related vegetation changes to river flood flows and fire events. Although saltcedar is still the dominant plant in the delta, native cottonwood ( Populus fremontii S. Wats.) and willow (Salix gooddingii C. Ball) trees have regenerated multiple times because of frequent flood releases from U.S. dams since 1981. Tree populations are young and dynamic (ages 5–10 years). The primary cause of tree mortality between floods is fire. Biomass in the floodplain, as measured by the normalized difference vegetation index on satellite images, responds positively even to low‐volume (but long‐duration) flood events. Our results support the hypothesis that restoration of a pulse flood regime will regenerate native riparian vegetation despite the presence of a dominant invasive species, but fire management will be necessary to allow mature tree stands to develop.

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Path analysis and multiple logistic-normal regression were used to model the interrelationships between stated herd management practices and herd 30-d postpartum incidence rates of dystocia, retained placenta, and clinical postpartum metritis, cystic ovary, milk fever, ketosis, left displaced abomasum, and mastitis. Management risk factors were obtained from a personal interview questionnaire. Data were from 2141 multiparous Holstein calvings from May 1981 through April 1982 in 32 commercial herds in the vicinity of Cornell University. Farms where the stated policy was to administer low calcium diets to the dry cows experienced more dystocia and retained placenta. More dystocia was experienced on farms where the stated policy was to administer extra vitamin D to dry cows, where dry cows were housed with the milking cows, or where calving occurred in maternity pens rather than stanchions. There was an increased likelihood of milk fever and left displaced abomasum on farms on which the stated policy was to lead feed. Farms where dairy farmers treated cases of retained placenta had more retained placenta than farms on which the treatment was done by the veterinarian. Farms reporting the practice of feeding the cows to increase their weight during the dry period had increased odds of ketosis.

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