1. One-hundred-and-ten British Friesian, British Friesian x Ayrshire or successive backcrosses to British Friesian heifer calves were allocated to three groups. Groups A and B were rapidly reared and fed a barley-beef diet which resulted in mean body-weight gains exceeding 1 kg/day (13 to 39 weeks) and group C was normally reared on summer grazing and hay plus concentrates in winter at a mean bodyweight gain never exceeding 0-74 kg/day. Animals in group A were first mated at an average age of 42-9 weeks (body weight, 302 kg). Groups B and C were mated later at average ages of 78-4 and 78-1 weeks (average body weights, 443 and 353 kg respectively). After the first calving all animals were fed and managed as a single group. 2. There were no significant differences between the proportion of heifers conceiving at first service in groups A (55-5%), B (66-7%) and C (72-4%). 3. There were no differences in the incidence of dystocia at first calving in heifers served by an Aberdeen Angus bull but 12 out of 19 heifers in group A served by a British Friesian bull had dystocia. 4. Average 305-day fat-corrected milk yields in the first four lactations in group A (18 animals) were 1959, 2918, 3545 and 3210 kg and in the first three lactations in group B were2450,3216and3310kgand in group C 3863,4694 and 4813 kg. Thus milk yield was significantly lower in all lactations for rapidly-reared animals irrespective of the age at breeding and was further significantly lowered in the first lactation of animals mated early. 5. There was a high incidence of laminitis and bloat in heifers reared on the barley-beef diet, but during lactation, there was a lower incidence of mastitis in the lower-yielding, rapidly-reared groups.
SUMMARYThe mammary glands of conventionally reared cows, never exceeding a live weight gain (LWG) of 0·74 kg/d, weighed 39% more and contained 68% more secretory tissue than glands of rapidly reared animals grown at 1·1 kg/d. In 11-month-old heifers reared at 3 rates of LWG (L, 0·57; M, 0·76 and H, 1·18 kg/d) gland weight was related to LWG, but dissected mammary parenchyma was heavier in animals on treatment L than on treatment H and followed a quadratic relationship. Parenchymal composition on treatment H was correlated to both age and body weight at puberty. No similar trend was observed in treatments L and M although group L animals had more ductal tissue and less fat than those of group M. Heifers from treatment L were reared during pregnancy at either 0·68 or 0·84 kg/d LWG (treatments LL and LH respectively) and heifers from treatment H at 0·58 kg/d (treatment HL). Total gland weight was unaffected by treatment, but the percentage by weight of secretory tissue in the gland in treatment HL was less than for treatments LL and LH. These experiments confirm that mammary development is permanently impaired by high rates of LWG in the first year of life. There was no impairment of mammary development in heifers reared moderately in the first year and more rapidly during pregnancy.
We identified, described, and defined models of academic institution-public health agency partnerships in Florida. The study involved a mixed-method research design using data collected from a survey of 67 county health department (CHD) administrators and directors in Florida, in-depth interviews of key informants, and reviews of relevant Florida statutes and other archival data providing context for the partnerships.Fifty-one of the CHDs (76%) participated in the survey. Most reported formal agreements involving 50 different academic institutions. The partnerships were perceived to enhance the local public health system's capacity. Recommendations focus on the need for a multitiered system for recognition of the partnerships and expansion of federal support for partnership beyond existing approaches. (Am J Public Health.
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