"Doctor my eyes": A natural experiment on the demand for eye care services.

Preventive health care is promoted by many organisations from the World Health Organisation (WHO) to regional and national governments. The degree of cost-sharing between individuals and the health care service affects preventive service use. For instance, out-of-pocket fees that are paid by individuals for curative services reduce preventive care demand. We examine the impact of subsidised preventive care on demand. We motivate our analysis with a theoretical model of inter-temporal substitution in which individuals decide whether to have a health examination in period one and consequently whether to be treated if required in period two. We derive four testable hypotheses. We test these using the subsidised eye care policy introduced in Scotland in 2006. This provides a natural experiment that allows us to identify the effect of the policy on the demand for eye examinations. We also explore socio-economic differences in the response to the policy. The analysis is based on a sample from the British Household Panel Survey of 52,613 observations of people, aged between 16 and 59 years, living in England and Scotland for the period 2001-2008. Using the difference-in-difference methodology, we find that on average the policy did not affect demand for eye examinations. We find that demand for eye examinations only increased among high income households, and consequently, inequalities in eye-care services demand have widened in Scotland since the introduction of the policy.

Blood antigen, serum protein, and milk protein gene frequencies and genetic interrelationships in Holstein cattle.

Gene frequencies at ten blood group loci, one serum protein locus, and four milk protein loci were determined for the Holstein-Friesian breed in the United States. The sample consisted of 8630 cows in 51 herds from 10 states. Because of the close linkage among casein subloci and the concimitant rarity of crossover-recombinant groups, casein gene combination or haplotype frequencies were determined also. As one means of comparison of systems, indices of homozygosity and number of effective alleles were calculated. These indices were proposed also to be useful tools for monitoring changes in genetic variability of breeds. Genotypes within codominant systems and phenotypes associated with paired-system combinations generally were not randomly occurring. Paired system phenotypes within the sire sample corresponded much more closely to expectations of randomness.

Oxygen consumption in heifers three months of age related to lactation milk energy.

Calibration techniques were developed for a modified commercial oxygen consumption computer. Oxygen consumption over 5 min by 130 3-mo-old dairy calves was measured 3 h after feeding. Subsequently, Estimated Transmitting Abilities were used to calculate the production potential for lactation milk energy (kcal/305-day lactation) for 88 of the animals. Correlations between lactation milk energy and oxygen consumption or oxygen consumption corrected for weight of calf were calculated by breed. Breed correlations were tested for homogeneity and pooled. The correlation coefficient between oxygen consumption and lactation milk energy was .20 with a 95% confidence interval of -.02 to .40.