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In this study, we developed a novel, simple, rapid, and low-cost colloidal gold-based immunochromatography method, with filter paper replacing nitrocellulose membrane as the substrate. To obtain adequately immobilized protein, chitosan was used to functionalize the filter paper. After conditions and parameters were optimized, the novel immunochromatography method was applied for detection of sulfonamide residues in milk. Quantitative detection was accomplished using a smartphone and Photoshop software (Adobe Inc., San Jose, CA), allowing us to screen 13 sulfonamides with a limit of detection ranging from 0.42 to 8.64 μg/L and recovery ranging from 88.2 to 116.9% in milk. The proposed novel method performed similarly to the conventional method that uses a nitrocellulose membrane as the transport medium, and it had lower cost and better usability because of the inexpensive and easily available filter paper.

Dairy cattle barns are a major source of NH3 emissions to the atmosphere. Previous studies have shown that the bedding material used in the barn can influence the magnitude of NH3 emissions, but little is known about which bedding characteristics are important in this respect. The aims of this study were to assess, at a laboratory scale, the relative importance of the chemical [pH, cation exchange capacity (CEC), C:N] and physical (urine absorbance capacity, bulk density) characteristics of 5 bedding materials (chopped wheat straw, sand, pine shavings, chopped newspaper, chopped corn stalks, and recycled manure solids) on NH3 emissions from dairy cattle urine. Recycled manure solids were the most absorbent of the bedding types (4.2 g of urine/g of bedding), and sand was the least (0.3 g of urine/g of bedding). When beddings were soaked in urine to their absorbance capacities, NH3 emissions over 48 h (expressed as a proportion of the urine N absorbed) were not significantly different among bedding types, despite differences in initial bedding pH, CEC, and C:N. When equal volumes of urine were applied to equal depths of dry bedding, NH3 emissions over 48 h were significantly less from sand and pine shavings (23 and 42% of applied urine N, respectively) than from chopped newspaper, chopped corn stalks, and recycled manure solids (62, 68, and 65% of applied urine N, respectively), whereas emissions from chopped wheat straw (55% applied urine N) only differed significantly from that from sand. Differences in the chemical characteristics of the beddings did not explain differences in emission; NH3 emissions increased linearly with CEC contrary to expectations, and there was no significant relationship with initial bedding pH. The physical characteristics of bedding materials were of more importance, as NH3 emissions increased linearly with absorbance capacity and decreased as the bulk density of the packed beddings increased.

Bacterial counts associated with recycled newspaper, wood shavings, and pelleted corn cobs used as bedding for lactating dairy cows were compared. Chopped newspaper and pelleted corn cobs had similar gram-negative bacterial, coliform, and streptococcal bedding counts. Staphylococcal counts in pelleted corn cobs were greater than in chopped newspaper. Conversely, gram-negative bacterial, coliform, and staphylococcal counts in chopped newspaper were greater than in wood shavings. Coliform and streptococcal counts did not differ between chopped newspaper and wood shavings bedding materials. Teat swab counts from cows bedded on pelleted corn cobs were greater than those from cows bedded on chopped newspaper for gram-negative bacterial, coliform, Klebsiella species, and staphylococci. Streptococcal teat swab counts did not differ between cows bedded on chopped newspaper and pelleted corn cobs. Cows bedded on chopped newspaper and wood shavings had similar gram-negative bacterial, coliform, and Klebsiella species teat swab counts. Streptococcal and staphylococcal teat swab counts were greater from cows bedded on chopped newspaper than those from cows bedded on wood shavings. Teat swab and bedding counts were correlated. In general, bacterial counts in bedding suggest no advantage in using chopped newspaper over pelleted corn cobs or wood shavings in reducing exposure of teats to environmental mastitis pathogens.

Eleven papers were compared for absorption of whey and for digestibility in vitro. Papers were squared, ground, and soaked in whey for 1,5, and 15 min and for 1, 6, 24, 48, and 72 h. Digestibility in vitro was determined on minimum and maximum whey absorption of each squared and ground paper sample. Whey absorption by squared papers increased with time. Ground samples absorbed more whey than squared ones and maximum quantities were absorbed within 1 to 5 min. Mean percent absorptions for ground telephone book covers, glossy magazines, computer cards, computer printout sheets, daily newsprint, telephone directory yellow pages, cardboard box, feedsacks, brown bags, telephone directory white pages, and coasters were: 31.0, 35.2, 35.4, 36.5, 43.9, 47.9, 51.0, 51.4, 51.7, 55.6, and 67.4. For seven papers, addition of whey increased digestibility. Four papers were either unchanged or decreased in digestibility. This depression of digestibility may have resulted from the high fat content of whey used. Based on in vitro digestibilities, we conclude that it is possible to recycle selected paper/whey combinations through ruminants.

Fifteen lactating Holstein cows in a 3×3 Latin square experiment determined effects of ground newspaper in the diet. Test components of the rations were: A) 20% cottonseed hulls; B) 10% paper and 10% cottonseed hulls; C) 20% paper. All animals received 2.3kg of long alfalfa hay daily. Proximate analysis and gross energy determinations indicated that the paper rations contained more crude fiber, ether extract, and gross energy and less crude protein and ash. Ink in the paper apparently caused higher gross energy values and probably increased ether extract. Estimates of dry matter digestibility by an in vitro technique were not significantly different being 77.4, 77.4, and 77.5 for the control, 10% paper, and 20% paper rations. Average daily ration intakes were significantly different among rations with intakes of 21.5, 17.0, and 12.5kg per day for the control, 10% paper, and 20% paper. Paper at 20% of the ration significantly lowered actual milk yields but did not significantly lower fat-corrected milk yield during the six weeks. Average daily fat-corrected milk yields for control, 10% paper, and 20% paper treatments were 15.9, 16.9, and 16.3kg. Milk fat percentages were 2.6, 3.1, and 3.4 with significant differences between treatments. Milk protein and solids-not-fat were not significantly different; however, there was an inverse linear response between treatment and milk protein percentage. There were small differences in ruminal volatile fatty acids with a significantly lower pH for the 20% paper compared with the control. Paper at 10% in the ration would maintain milk fat percentage without reducing actual milk production during six weeks.

In vitro dry matter disappearances were determined for 11 paper sources and three complete rations containing 0, 10, and 20% newsprint. Inoculum was from an alfalfa hay-fed steer. Alfalfa hay, brome hay, and Solka Floc were reference substrates. Brown wrapping paper and brown cardboard had the highest dry matter disappearances of 90.8 and 77.8%; whereas four glossy or slick magazine papers had significantly lower values of 46.1, 45.1, 41.3, and 41.0%. Newsprint with black ink, without ink, and with colored inks had dry matter disappearances of 33.2, 32.6, and 26.5%, which were significantly lower than those of the glossy magazine papers. Lowest dry matter disappearances of 24.0 and 20.1% were from two magazine papers. The complete rations had 77.9, 80.1, and 81.8% dry matter disappearances for the 0, 10 and 20% paper rations. These data indicate substantial differences in digestibilities of various paper sources.