1. A series of grazing behaviour observations on 10 sets of lactating identical twins is described. Four fortnights distributed over the main lactation period were covered. In three of the fortnights, the observations were made on six 24 hr. periods, while in the remaining fortnight the cows were observed on all 14 days.2. Anoutstanding feature of the grazing behaviour of dairy cattle is its variability, due to external and internal conditions.3. Of the external factors, climate (in a temperate zone) is relatively unimportant.4. The quantity and quality of the herbage offered are of importance in modifying the grazing behaviour of dairy cattle. Under adverse pasture conditions there is, in general, an increase of total working time (grazing + ruminating): grazing time increases with scarcity of herbage and with mixed quality, while ruminating time is prolonged by poor quality grass.5. Ruminating time is strongly dependent on the quantity and quality of the ingested grass, but the relationship is, for various reasons, obscured in a field trial such as the present.6. The adaptation of grazing habits to new conditions is very rapid.7. Feed requirement for milk production is the most important internal factor determining variation in the length of grazing time.8. Inheritance × environment interactions as a source of variations in grazing times are due to the following factors:(a) Differences amongst twin sets in lactational persistency, which presumably cause parallel differences in feed requirements.(b) Differences in the response of high and low producing twin sets to varying pasture conditions.(c) Non-analysable idiosyncrasies common to the members of some twin sets.9. Twin sets graze and ruminate at a characteristic rate.

1. Four trials on methods of bloat-prevention vare described: (a) A comparison of ‘break’ grazing and normal ‘rotational’ grazing without restriction of feed in either case. Break grazing observations covered two and five breaks per day.(b) A comparison of these two systems where ‘break’ grazing involved restriction of area available to the cows, and ‘breaks’ varied from seven to eleven per day.(c) Comparison of ‘off and on’ grazing with normal rotational methods in an attempt to force changes in grazing pattern.(d) Comparison of the same pasture grazed at different lengths under rotational grazing methods.2. Grazing behaviour and degree of bloat were noted.3. In general, the results showed that, irrespective of number of breaks, break grazing with or without restriction gave no effective control of bloat.4. There were definite indications that a strictly enforced system of ‘off and on’ grazing could afford considerable practical control.5. Long feed proved definitely safer than feed of the same botanical composition grazed at shorter stages of growth.6. It was found that cows on potentially dangerous grass had short grazing times with few periods of intense activity. Thus, the oft-stated opinion that bloat is caused by cows eating greedily of dangerous pastures was not substantiated. On the contrary, cows on such pasture showed marked reluctance in their grazing activity.7. Bloat-producing swards were also associated with reduced rumination time, even in respect to cows showing no symptoms. Bloated cows showed generally very low rumination times.8. Many of these observations were made on identical twins. From the similarity in their behaviour, it can be concluded that inheritance is an important factor affecting the occurrence of bloat amongst cows grazing the same herbage.9. In the early stages of bloat, ruminal movement and belching increased in frequency and intensity. This is contrary to the theory that bloat is due to rumen atony. Atony was observed only in the advanced stages of the trouble.

Outside storage with no protection from the weather contriutes to the frequent large storage losses for round‐baled hay compared with small rectangular bales stored inside. We evaluated losses in dry matter (DM) yield and forage quality of round bales bound with solid or woven‐mesh plastic instead of sisal twince. Round bales of tall fescue (Festuca arundinacea Schreb.) averaging 706 ± 19 lb and 18.2 ± 1.4% moisture were wrapped with two layers of plastic mesh or solid self‐adhesive plastic wrap and placed on grass sod for storage. Twine‐tied bales were stored on sod or indoors for comparison. Trials were conducted in 1990 and 1991, each with four replicates of each treatment. Dry matter losses and changes in crude protein (CP), neutral detergent fiber (NDF), and in vitro dry matter disappearance (IVDMD) were measured after 1 yr of storage. Weathering affected layers 0, 0.6, 2.1, and 4.4 in. deep for indoor, solid plastic, plastic mesh, and twine‐tied bales stored outside, respectively. Storage DM losses of 18.2% for twine‐tied bales stored outside were reduced to 10.6% by plastic mesh wrap but were lowest for solid‐plastic‐wrapped (3.6%) and inside‐stored bales (5.7%). Weathered hay from twine and plastic mesh‐wrapped bales fell approximately 20 percentage units in IVDMD during storage. Weathering and storage treatment effects on CP and NDF were small. Using solid plastic wrap or plastic mesh wrap as binding materials for bales stored outside saved DM and solid plastic wrap improved hay quality over twine‐tied bales. Research Question Storage losses of round bales are usually greater than those of rectangular bales but routine storage of round bales outside without protection from moisture is largely responsible for the difference. Plastic mesh wrap and solid plastic wrap have been developed as binding materials to replace twine with the proposed advantage of reducing losses for round bales that are stored outside. The objective of this study was to evaluate the utility of some recent developments in round bale binding materials for reducing losses in DM yield and forage quality during hay storage. Literature Summary Large round bales and other larger hay packages minimize labor required for hay baling and transport. In the humid regions of the US, however, storage losses of round bales are frequently much greater than for similar hay in rectangular bales. It is clear from previous research that round bales of dry hay stored indoors lose similar amounts of DM during storage as rectangular bales, indicating that storage conditions account for most of the additional losses experienced with large round bales. Losses in forage quality may be very great for round bales stored outside with no protection from the weather. Labor for covering bales and bale tying time can be reduced by applying self‐adhesive solid wrap or porous plastic wrap (net wrap) materials instead of twine during the baling process. Both materials are also hypothesized to reduce weathering losses by shedding precipitation during outside storage of ...

1. A series of observations on the grazing behaviour of identical twin cattle on two contrasting systems of pasture management—rotationally and continuously grazed—is described.2. The rotationally grazed cows averaged only 11 min. (day/cow) shorter feeding time and 18 min. shorter ruminating time than their continuously grazed co-twins. The total time they spent in work was thus 29 min. shorter.3. While the average differences in total work over the whole trial was not great, the continuously grazed cows worked for appreciably longer daily periods at the time of seasonal feed shortage during which time the rotationally grazed cows were buffered by their pasture diet being supplemented with silage.4. The differences in grazing behaviour between the cows of the two treatments, together with the magnitude of the seasonal variations which occurred in both groups, indicated that dairy cows attempt to maintain a stable production in the face of adverse pasture conditions by increasing their feeding time.5. Previous conclusions based on observations of uniformly treated twins regarding the importance of heredity in the determination of grazing behaviour were fully confirmed.

1. An experiment is described in which the effect of the level of nutrition, as determined by stocking rate and the use of supplementary concentrates, on milk yield and efficiency of production was studied.2. Three levels of nutrition were used: Treatment (A)—one milking cow per acre plus 1 lb. of concentrate mixture for each 5 lb. of milk produced. Treatment (B)—one milking cow per acre—no concentrates. Treatment (C)—one milking cow per sixtenths of an acre—no concentrates.3. Fifteen sets of identical twins were used per year over an experimental period of 3 years. The groups were rotationally grazed with a daily shift to a fresh pasture on a 14-day rotation. Ninety complete lactations were available for analyses.4. The A cows produced 45% and the B cows 16% more f.c.m. than the C cows. Per unit area, however, the C treatment produced 30% more than the B.5. Significant differences in milk composition were established, but these were of much smaller magnitude than those in milk yield.