ABSTRACT
O estudo da distribuiçäo extra e intraparenquimal dos ductos biliares dos raros "lobos brasileiros" um exemplar de "lobo guará Chrysocyon brachyurus" e 3 exemplares de "cachorro do mato" Cerdocyon thons, revelou a presença do ducto hepático, no Chrysocyon brachyurus, porém, o mesmo estava ausente nos 3 animais de outra espécie, uma vez que o ductus hepaticus dexter e o ductus hepaticus sinister convergem para o ductus cysticus (triconvergência). Um arranjo variável na distribuiçäo de outros ductos biliares foi observado nos 4 animais estudados. As semelhanças e diferenças entre estes achados com o cäo doméstico sem raça definida, Pastor Alemäo e Pequinês também estäo indicados
Subject(s)
Animals , Animals, Wild/anatomy & histology , Common Bile Duct/anatomy & histology , Wolves/anatomy & histologyABSTRACT
Feed efficiency measures, gross energy (solids-corrected milk/estimated energy intake), N (milk N/N intake) utilization, and apparent digestibilities of ration dry matter and N were calculated for 34 daughters of 21 Holstein and 29 daughters of 18 Jersey sires in first and second trimesters of lactation. Cows were studied in N balance trials and were fed ad libitum corn silage-based, complete rations formulated to meet average nutrient requirements. The objective was to determine whether these breeds differ in rates of converting dietary protein or energy to milk protein or milk energy. Holstein and Jersey did not differ for digestibility of ration dry matter in either trimester of lactation. They also converted dietary protein to milk protein at similar rates. Energy efficiencies of Holstein and Jersey did not differ in first trimester, but Holstein exceeded Jersey in second trimester. Because intake of dry matter by Jersey increased about 4% from first to second trimester (opposite of Holstein) and N balance was higher than for Holstein, Jersey cows may have been repleting more adipose tissue. We suggest no comparative advantage for Jersey in spite of higher ratios of milk to body weight and feed intake less than Holstein.
Subject(s)
Cattle/metabolism , Dietary Proteins/metabolism , Energy Metabolism , Milk Proteins/biosynthesis , Animals , Female , Lactation , PregnancyABSTRACT
Feed efficiency measures, gross energy (solids-corrected milk/estimated energy intake) and nitrogen (milk nitrogen/nitrogen intake) utilization, and apparent digestibilities of ration dry matter, nitrogen, acid detergent fiber, and starch were calculated for 134 samples of 75 daughters of 31 Holstein sires. Cows were in 5- to 9-day nitrogen balance trials in first and second trimesters of lactation and were fed for ad libitum consumption corn silage-based complete rations formulated to meet average nutrient requirements. The objective was to test the hypothesis that feed efficiency diminishes as milk increases from selection. The sample of cows closely approximated the distribution of genetic ability for milk of the Holstein breed. Nonsiblings of same parity (one, two, three or more), calving within 2 wk of each other and differing by at least 140 kg estimated transmitting ability, were paired in nitrogen balance trials. Evidence for diminishing returns to increased transmitting ability for milk was nil for any measure of feed efficiency. Energy efficiency showed linear increases when regressed on cow transmitting ability for fat-corrected milk, but other measures of dietary utilization were unrelated to milk yield.
