Performance of Lactating Crossbred Cows under Different Housing Systems During Summer in Konkan Agro-ecological Conditions”
An investigation was carried out on nine lactating crossbred cows (J×L) cows which were allotted randomly into three comparable shelters in switch over design. Three different type of shelters were, 1- Asbestos roofing; 2- Paddy straw thatched roof house; 3 - White painted asbestos roof. Temperature humidity index was higher in macro -environment followed by thatched roof shed, white painted asbestos roof and asbestos roofing. Thatched roof shed had significant (P<0.05) incremental effect on the milk production and milk composition of cows than the cows in white painted roof shed and asbestos roof shed during summer. Overall paddy straw thatched roof shed effectively ameliorates environmental temperature, humidity and THI during summer season in the Konkan region.
Effect of high temperature and dietary fat on performance of lactating cows.
Abstract Two Latin squares balanced for carry-on effects were used for evaluation of productive performance of 12 Holstein cows fed high levels of fat under environmental temperatures: cool 15–24 C and hot 32.2 C, 60% relative humidity. The cows were fed 1.25 kg alfalfa-grass hay per 100 kg body weight and one of three concentrates: control (without added lipids), oil (10% soybean oil), or fat (10% hydrogenated vegetable fat, iodine value 48) replacing corn on a weight basis. Elevated temperature resulted in a marked depression in yield of milk and milk fat, SNF, and protein, of body weight, feed intake, rumen VFA, acetic:propionic ratio, and gross efficiency; water intake and rectal temperature increased. Significant ration effects were observed only in the case of FCM production, where the oil-fed cows excelled. Environmental effects were independent of ration effects, except in water intake, rumen total VFA, and acetic acid levels, where interactions were noted. Significant period effects from repeated exposures to heat stress were noted only in FCM yield, water consumption, and rumen propionate. The drastic environmental stress imposed in this study served to mask many of the anticipated ration effects.
Effects of thyrotropin-releasing hormone and a thyrotropin releasing hormone analog on growth and selected plasma hormones in lambs.
An 8-wk growth trial was conducted to assess the effects of continuous infusion of thyrotropin-releasing hormone (TRH) and an active TRH analog less than Aad-His-Pro-NH2 (the less than Aad is L-pyro-alpha-aminoadipic acid) on growth trial performance, carcass composition and hormone profiles of growing lambs. Both drugs were infused at 600 micrograms X lamb -1 X d -1 with 16 lambs/treatment. Both TRH and less than Aad-His-Pro-NH2 decreased average daily gain (ADG; P less than .01) and increased feed conversion (FC; P less than .01) compared with saline infused controls. Average daily feed intake was not altered. Carcasses of lambs given TRH or less than Aad-His-Pro-NH2 contained fewer kilograms of moisture (P less than .05) and appeared to contain fewer kilograms of protein. Thyrotropin-releasing hormone and less than Aad-His-Pro-NH2 increased thyroid gland weights (P less than .05), but pituitary gland weights were not different. Plasma thyrotropin (TSH) concentrations were increased by both drugs compared with control lambs, peaking at 4 to 7 d after initiating infusion. However, by 14 d, TSH concentrations returned to control levels. Triiodothyronine (T3) and thyroxine (T4) were elevated by both drugs over the entire 8-wk trial, with peak levels reached at 10 d and maintained for the duration of the study. Both TRH and less than Aad-His-Pro-NH2 increased prolactin over the entire period. Growth hormone levels were not altered by either drug. The effects of less than Aad-His-Pro-NH2 infusion on growth trial performance, carcass composition and hormone profiles of growing lambs were very similar to TRH. The negative effects of TRH and less than Aad-His-Pro-NH2 infusion on ADG, FC and carcass protein appear to be the result of elevated T3 and T4 levels.